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HP 6256B User's Manual

1. ee poene MODEL 62648 SEMAR an ND ABOVE 6267B SERIALS LS EN AND ABOVE x Microfiche Part No 5950 1766 HEWLETT OPERATING SERVICE Lud E 62718 52748 _ HP Part No 8550 1765 N 4 MODEL 62558 SERIALS 1542A 01387 AND ABOVE s MODEL 52538 SERIALS 1542A 01227 iAND ABOVE GREAT Re uS Y Y A B m MODEL 6271 SERIALS 1543A 00746 AND ABOVE MODEL 62748 SERIALS 1539 0181 1 ANERABOVE s listed a changa page may ingirded Valuetronics international in inc 1 800 552 8258 S MASTER COPY 4 7 ex og po t THE REMEDIES PROVIDED HEREIN ARE THE CUSTOMER S SOL L ae 2 E CERTIFICATION Hewlett Packard Company certifies that this product met its published specifications at time of shipment from the factory Hewlett Packard further certifies that its calibration measurements are traceable to the United States National Bureau of Standards to the extent allowed by the Bureau s calibration facility and to the calibration facilities of other international Standards Organization members mM 43 Misi eu WARRANTY This Hewlett Packard hardware product is warranted against defects in material and workmanship for a period of one from date of delivery HP software and fi
2. Bias supply 12V unrequiated bias voitage 11 CR34 Reverse voltage protection Output voltage En NM CR30 CR32 Voltage clamp circuit CC load regulation MC R75 R78 See para 5 84 and 5 86 Output voltage ripple imbalance and preregulator waveforms Preregulator control turn on delay CR36 38 40 Preregulator control CR43 44 51 CR52 CR45 47 50 Preregulator Output voltage R75 See para 5 86 VR1 VR2 Reference supply 6 2V and 6 2V reference voltages Voltage clamp circuit CC load regulation i R30 See para 5 82 Mixer amplifier stabilization CV transient response diode R108 R109 See para 5 88 and 5 90 VR5 Crowbar Trip voltage VR6 Bias voltage supply 2 4V and 4 8V bias voltages 5 14 B eua aor 5 60 REPAIR AND REPLACEMENT 5 61 Section VI of this manual contains a list of replace able parts 1f the part to be replaced does not have a standard manufacturer s part number it is a special part and must be otbained directly from Hewlett Packard After replacing a semiconductor device refer to Table 5 8 for the checks and adjustments that may be necessary 5 62 ADJUSTMENT AND CALIBRATION 5 63 Adjustment and calibration may be required after performance testing troubleshooting or repair and replace ment Perform only those
3. Table 6 4 Replaceable Parts REF DESIG MFG MFG HP AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER OPTION 010 Chassis Slides slides 55 168 20 21 25 32 BK0106C 1490 0872 6256B 64B 67B 74B spacer slide qty 2 5000 6234 OPTION 013 3 Digit Decadial Voltage Control R10 6256B var ww 2k 10 turn Series 8400 2100 2029 62638 64B var ww 5k 10 turn Series 8400 2100 1865 6265B 66B 67B var ww 10k 10 turn Series 8400 2100 1866 6271B 74B var ww 20k 10 turn Series 8400 2100 1867 3 digit turns counting dial 411 1140 0020 OPTION 014 3 Digit Decadial Current Control R16 6256 64 6263B 65B 66B 67B 718 74 Series 8400 Series 8400 var ww 200 10 turn var ww 1k 10 turn 84048 2100 1863 84048 2100 1864 3 digit turns counting dial 411 12697 1140 0020 OPTION 020 Adjustable Voltage Programming 0 07716 0757 0473 fxd film 221k 1 1 8W var ww 15k CT 100 4 84048 2100 0896 fxd film 249k 1 1 8W CEA T 0 07716 0757 0270 var ww 15k CT 100 4 84048 2100 0896 OPTION 021 1 Adjustable Current Programming 1 i R125 6256B 64B fxd film 23k 1 1 8W CEA 993 0698 3269 6263B 65B 66B 67B fxd film 200k 1 1 8W CEA 993 0757 0472 718 748 R126 var ww 15k CT 100 4 2100 0896 R127 fxd film 390k 1 1 8W CEA 993 0698 5093 R128 var ww 1
4. 4 8128 CURRENT m 15K ZERO EH LJ f 6 RI27 i 390K 1 178 RD __ A4 e RIA RIS 23 CIRCUIT ANT CLAMP 5 1700 124V 6 2V 48y uo 9 228 222A RSO 250 390 E n QIQ OPTION 020 022 040 ONLY ____ 12 22 8 i VOLTAGE 2 62 15K ZERO RI23 1 249K ew 854 SEE TABLE x pmo iz E TO M TER CIRCUIT MONITORING TERMINAL R2 e RIO SEE SEE TABLE TABLE ail VOLTAGE e ci TABLE TABLE a 259 100 MONITORING oO TERMINAL _ ee OVERVOLTAGE PROTECTION CROWBAR g UNREG TO PREREG ROZ 0 125 5w RIO 200 iw CR56 412 4 5 A TABLE RIOS OVERVOLTAGE dm 8 TABLE 0 Lnd _ T 5 su M fl CIRCUIT oe CR2I SHORT CIRCUIT PROTECTION 0 1 CONTROL SEE TABLE 2 24V 12 UNREG 22 I2 4V 412 4V 6 ud 22H ze 20K 144 126 0 Z1 f pon nn FSS le le Ts 1 1 1 5 1 2a 2 o ag 2K FROM
5. CR20 shorted Connect oscilloscope between a Normal waveform Proceed to step 2 TP59 and TP81 b Little or no voltage Defective O18 019 C18 Proceed to step 3 Connect oscilloscope between a Normal waveform Defective A2CR1 A2L1A A2L1B TP53 4 and TP55 Ti A2C1 A2C3 b Little or no voltage Defective T3 CR40 R84 Proceed to step 3 WARNING To avoid a potentially lethal shock hazard a differential oscilloscope must be used in making this measurement 5 12 Table 5 7 Preregulator Troubleshooting See Figure 4 4 for Waveforms Continued AU Connect oscilloscope between a Amplitude incorrect a Defective 022 C15 C17 CR43 CR44 TP73 and 81 R78 R86 or R87 b Period incorrect b CR38 defective Proceed to step 4 4 Connect oscilloscope between Amplitude reference Defective CR28 CR33 CR36 CR37 TP64 and TP67 or period incorrect CR38 Check R70 Connect oscilloscope between Amplitude dc reference Defective CR27 CR31 R68 R69 C16 67 and TP81 or period incorrect Table 5 8 Checks and Adjustments Required After Semiconductor Replacement REFERENCE FUNCTION OR CIRCUIT CHECK ADJUST 21 Constant voltage and constant Constant voitage CV line and load regulation R6 or R8 or current differential amplifiers Zero volt output Constant current CC line and R124 if Option load regulat
6. 1 BEN LI i MODEL 52568 52648 52678 ONLY 783 51 1 i 1 i C30 t 1 i i i 4 1 1 1 1 1 1 5 TABLE a 3 ae 4 MODEL 62289 ONLY CONTROL CROWBAR a C8 20 LJ i 1 1 AE m OUTPUT amp REGULATOR 5 GENERATOR SAMPLER FROM 70 SAMPLER PREREGLL ATOR P WTROL_CIRCUIT___ 1 6 2 TABLE 864 TABLE t TABLE TABLE SERIES REGULATOR DRIVER SHORT CIRCUIT 2 4V ERROR MIXER AMPLIFIER AMPLIFIER TURN ON l 12 4 12 3 29 5 TABLE 15K 20K 21 5 Z1 EE ESAE 1 i 16 13 I A 5 95 E 22865 FROM CONSTANT VOLTAGE 35 6 2 NOTE l4 R28 560K 12 UNREG 62v 4 8 VRE 2 37N hn aon mme eae eke 12V UNREG R32 red 2 4V 24 METER CIRCUIT p FROM CURRENT SAMPLING RESISTOR E FROM CURRENT SAMPLING RESISTOR OVERVOLTAGE
7. 75915 75915 75915 75915 75915 28480 28480 28480 28480 28480 28480 28480 DESIG PART NUMBER 5080 7192 1902 1221 1902 3070 1902 0049 1902 3002 1820 0240 1810 0042 0160 4065 0160 4323 0160 0899 1884 0218 1884 0222 5080 1780 0698 3338 0698 3631 0698 3626 0698 3628 0837 0117 0160 2568 0160 2568 3105 0035 1450 0419 1450 0306 2110 0342 2110 0227 2110 0051 2110 0055 2110 0234 1120 1170 1120 1159 1120 1171 1120 1161 1120 1173 1120 1162 1120 1174 Table 6 4 Replaceable Parts REF DESIG MFG MFG HP AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER M2 6256B 64B ammeter 0 24A 28480 1120 1178 6263B ammeter 0 12A 28480 1120 1168 6265B 71B ammeter 0 44 28480 1120 1166 6266B ammeter 0 6A 28480 1120 1167 6267B ammeter 0 12 28480 1120 1176 6274B ammeter 0 18A 28480 1120 1177 R10 VOLTAGE COARSE controi 62568 ww 2 5k Series 43 12697 2100 2745 6263B 64B var ww 5k Series 43 12697 2100 1853 62658 66B 67B var ww 10k Series 43 12697 2100 1854 62718 74B var ww 20k Series 43 12697 2100 1855 R11 VOLTAGE FINE control 6256 63 64 67 var ww 50 Series 43 12697 2100 1858 62658 668 var ww 100 Series 43 12697 2100 1987 62718 748 ww 1k Series 43 12697 2100 1847 R16 CURRENT COARSE control 6256B 64B var ww 200 Series 43 12697 2100 1856 6263B 65B 66B 67B var ww 1k Series 43 12697 2100 1847 718 748 R1
8. would be 25V 5mA 5000 ohms 3 53 When operating three supplies in auto series find 2 by dividing the voltage programming current of the second slave calculated as in paragraph 3 52 into the maximum voitage expected from the first slave 3 54 Setting the Voltage Controls The voltage each slave supply contributes is determined by its voltage control setting The output voltage of the first slave supply tracks the voltage of the master and the voltage of the second MOOELS 62568 62648 52678 62748 Al 2 A4 5 A6 S A9 AIO 5 Figure 3 8 Auto Parallel Operation of Two Units 3 8 MODELS 62568 62648 62678 62748 Al A2 A4 A5 5 49 AD 5 MASTER AB GND 991910199 2 4 5 S A9 5 elelelele 2 elelelo vr GND 2 A3 A4 5 AG S A9 AD 5 2 po 21212121219 MODELS 62638 62658 62668 62718 Al 2 4 5 5 GNDAB 5 2 4 5 5 210149019 501 pru e Figure 3 9 Auto Parallel Operation of Three Units 3 9 slave if used tracks the voltage of the first stave For this reason the voltage of the master must be adjusted to maximum and then each slave in turn must be set to the corresponding voltage desired during initial setup of the auto series combination Once
9. ww 600 5 SW fxd ww 1k 5 5W fxd ww 680 5 SW fxd ww 1k 5 5W fxd comp selected fxd comp 3 3 5 1 2W fxd comp 750k 5 1 2W fxd comp 1 5M 5 1 2W fxd comp 560k 5 1 2W fxd comp 1M 5 1 2W fxd comp 3 3M 5 1 2W fxd ww 3k 5 3W fxd ww 14k 3 2W PART NUMBER 2N3898 1N485 MM2258 2N4036 TZ 173 2N4036 TZ 173 2N3391 TZ 173 2N3391 2N3417 2N3391 TZ 173 2N3391 2N3417 242 1025 242 1025 4305 8205 1615 2415 CEA 0 EB 3645 CEA 0 EB 5645 243E6015 RS 5 243E6815 RS 5 EB EB 33G5 EB 7545 EB 1555 EB 5645 1055 3355 242 3025 222E14K00H leads must be properly bent 6 6 CODE 04713 56289 56289 56289 56289 56289 56289 01121 01121 01121 01121 0771 01121 07716 01121 56289 91637 56289 91637 01121 01121 01121 01121 01121 01121 01121 56289 56289 PART NUMBER 1844 0058 1901 0033 1854 0271 1853 0041 1853 0099 1853 0041 1853 0099 1854 0071 1853 0099 1854 0071 1854 0087 1854 0071 1853 0099 1854 0071 1854 0087 0813 0001 0811 1806 0686 4305 0686 8205 0686 1615 0686 2415 0757 0427 0686 3645 0757 0460 0686 5645 0811 1860 0812 0099 0811 2099 0812 0099 0686 0335 0686 7545 0686 1555 0686 5645 0686 1055 0686 3355 0812 0010 0811 2692 Table 6 4 Replaceable Parts REF DESIG MFG MFG MODELS DESCRIPTION PART NUMBER CODE PART NUMBER R19 fxd comp
10. 6263 8 658 668 718 5060 7952 0403 0150 5000 9440 62568 638 648 658 668 678 718 62748 06274 00013 Note 3 Models 62568 648 678 748 only The rear panel components of the remaining models are included under Chassis Mechanical 6 14 nd Table 6 4 Replaceable Parts REF DESIG MFG MFG HP AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER 6256B 64B 67B 74B handles qty 2 28480 5020 5715 62638 658 668 718 handles aty 2 28480 5020 5751 screw 10 32 1 75 for handles 28480 2680 0173 qty 4 6263B 65B 66B 71B rear panel 28480 5020 2502 6263B8 65B 66B 71B heat sink qty 2 28480 5020 8065 62638 658 668 71 hex standoff 250 R54 qty 2 28480 0380 0716 62638 65B 66B 71B barrier strip cover for 15 term strip 28480 5000 3098 62568 648 678 74 barrier strip cover for 11 and 6 term 28480 5000 9452 strips 6256B 64B 67B 74B barrier strip cover for ac input 28480 5000 6249 6263B 65B 66B 71B line cord 8120 0852 62 3B 65B 66B 71B strain relief bushing line cord 0400 0098 6256B 64B 74B capacitor clamp C13 14 28480 5000 6017 62678 capacitor clamp C13 28480 06267 00001 6256B 64B 67B 74B capacitor clamp C20 0180 0078 62638 658 668 718 capacitor clamp C14 28480 5000 6223 62638 658 668 718 capacitor clamp C20 28480 5000 6267 62568 648 678 748 grommet 7 8 2 28480 0400 0063 62568 648 748
11. Bloomfield N J James Millen Mfg Co Inc Malden Mass J W Miller Co Compton Calif Cinch City of Industry Calif Oak Mfg Co Div of Oak Electro Netics Corp Crystal Lake 111 Bendix Corp Electrodynamics Div No Hollywood Calif Palnut Co Mountainside N J Patton MacGuyer Co Providence R I Phaostron Instrument and Electronic Co South Pasadena Calif Philadelphia Steel and Wire Corp Philadelphia Pa American Machine and Foundry Co Princeton Ind TRW Electronic Components Div MANUFACTURER Camden N J Resistance Products Co Harrisburg Pa Hlinois Tool Works inc Elgin 111 Everlook Chicago Inc Chicago Ill Stackpole Carbon Co St Marys Pa Stanwyck Winding Div San Fernando Electric Mfg Co Inc Newburgh N Y Tinnerman Products inc Cleveland Ohio Stewart Stamping Corp Yonkers Waldes Kohinoor Inc L 1 C N Y Whitehead Metals inc New York Continental Wirt Electronics Corp Phitadelphia Pa Zierick Mfg Co Mt Kisco Mepco Morristown N J Bourns Ine Riverside Calif Howard Industries Racine Wisc Grayhill Inc La Grange Ili International Rectifier El Segundo Calif Columbus Electronics Yonkers N Y Goodyear Sundries amp Mechanical Co Inc New York N Y Airco Speer Electronic Components Du Bois Pa Sylvania Electric Products Inc Emporium Pa Switchcraft Inc Chicago 111 Metals and Controls Inc Attieboro Mass 6 4 82866
12. 62638 648 62658 668 678 62718 62748 R87 6256B 63B 64B 65B 66B 678 71B 62748 R90 R91 R94 R96 62568 648 718 748 62638 62658 62668 62678 R97 R98 6256B 638 64B 65B 66B 678 74B 62718 R99 62568 648 658 668 678 71B 74B 6263B R101 R102 R103 R104 R105 R106 6256B 63B 64B 65B 668 678 62718 748 R107 R108 6256B 648 678 74B 6263B 65B 66B 62718 R110 R112 R113 R114 T2 62568 63B 64B 65B 66B 67B 71B 62748 Table 6 4 Replaceable Parts DESCRIPTION fxd comp 51k 5 1 2W fxd comp 100k 5 1 2W fxd comp 200k 5 1 2W fxd comp 300k 5 1 2W fxd comp 360k 5 1 2W fxd comp 3 3k 5 1 2W fxd comp 6 2k 5 1 2W fxd comp 180k 5 1 2W fxd comp 15k 5 1 2W fxd comp 10k 5 1 2W fxd met ox 270 5 2W fxd met 560 5 2W fxd met ox 1 5k 5 2W fxd met ox 1k 5 2W fxd met ox 560 5 2W fxd comp 5 1k 5 1 2W fxd comp 270 5 1 2W fxd comp 1 5k 5 1 2W fxd comp 100 5 1 2W fxd comp 300 5 1 2W fxd comp 200 5 1W fxd ww 0 125 10 SW fxd comp 200k 5 1 2W fxd ww 135 5 5W fxd comp 10 5 1 2W fxd film 470 1 1 4W fxd film 1 33k 1 1 4W fxd comp 510 5 1 2W fxd film 1 5k 1 1 8W fxd film 1 33k 1 1 4W fxd film 2k 1 1 4W fxd comp 10k 5 1 2W fxd comp 4 7 5 1 2W fxd comp 3 9k 5 1 2W fxd film 4 7k 5 1 4W power transformer power transformer 6 9 MFG PART NUMBER EB 5135 1045 2045 3045 3
13. C23 26 6256B 64B 67B 74B CR11 62638 668 CR21 62568 538 648 678 748 62668 CR22 23 62568 638 648 67B 74B 6266B CR24 62568 638 648 67B 748 6266B CR34 6263B 66B 6263B 66B 62718 Table 6 4 Replaceable Parts DESCRIPTION power NPN Si power NPN Si current sampling resistor fxd low t c alloy 025 ohms fxd low t c alloy 050 ohms fxd low t c alloy 0333 ohms Chassis Electrical fan cooling 115V 50 60Hz fxd elect 34000uF 30V fxd elect 40000uF SOV fxd elect 22000uF 75V fxd elect 34000uF 30V fxd elect 40000uF 50V fxd elect 22000uF 50V fxd elect 22000uF 75V fxd elect 8600uF 25V fxd elect 4500uF 55V fxd elect 5000uF 50V fxd elect 5000uF 45V fxd elect 1600uF 85V fxd cer 500V diode Si 100V 40A diode Si 100V 40 diode Si 100V 12A diode Si 100V 40A diode Si 100V 12A diode Si 100V 40A diode Si 100V 12A diode Si 100V 40A power NPN Si power NPN Si center collector lead is cut off 6 12 MFG PART NUMBER 2N3772 60675 WS 2107FL 55 32D D 32D D42343 DOB 32D D38829 DOB 2D D40073 DOB 4 e 32D D40073 DQB 32D D42343 DQB 32D D40078 DQB 32D D38829 DQB 32D D46882 DOB 32D D45312 DQB 36D7119 36D D38008 DOB 3205279 208 33617A 1N1184A 1 1184 1N1200A 1N1184A 1N1200A 1N1184AR 1N1200A 1N1184A 40250 60744 56289 56289 56289 5
14. R9 R12 R13 R18 R19 R20 C1 noisy or drifting Q13 shorted Table 5 4 Feedback Loop isolation Fuse blown or breaker tripped a Check rectifier filter and triac for short Proceed to step 3 Fuses and breaker OK b Proceed to step 2 output voltage high Fuses and breaker OK output voltage low c Proceed to step 2 Table 5 4 Feedback Loop Isolation Continued inspect OVERVOLTAGE amp 4 Check setting of OVERVOLTAGE on front panel ADJUST R109 Check CR57 for short Proceed to step 3 b Off output voltage high Check OVERVOLTAGE ADJUST R109 Check CR57 for open Also check Q24 and Q25 Proceed to step 3 c Off output voltage low Check OVERVOLTAGE ADJUST R109 Check CR57 for open Also check Q24 and Q25 Proceed to step 3 isolate fault to series regulator a Output voltage normal Faulty preregulator Disconnect or preregulator by proceeding variable from 0 volts to external source and proceed to as follows about 9 volts Table 5 7 1 Open the gate lead of b Output voltage high High voltage condition in series triac A2CR1 TP53 Varying controis has little regulator Proceed to Table 5 5 2 Observing correct or no effect Leave external source connected polarity connect a small dc Output voltage low Low voltage condition in series power supply across input Varying controls has little regulator loop Proceed to Table capacitor C13 or C14 A or no effe
15. S and 5 terminals directly to the and ends of the load Observe the precautions outlined under paragraph 3 25 3 48 Auto Parallel With Remote Programming When two or three supplies are connected in auto paralle their combined output voltage current or both can also be remotely programmed Refer to the appropriate sections of paragraph 3 32 for the additional rear panei connections required and make these connections to the master supply only Observe all precautions outlined in the paragraphs on remote programming The simultaneous use of remote sensing and remote programming is also possible during auto parallel operation 3 40 Auto Series Operation 3 50 Figures 3 10 and 3 11 show the rear panel and circuit board interconnections required to operate two or three supplies in the auto series mode This mode of operation allows two or three series connected supplies to be simultaneously programmed by the voltage and current controls of a master supply The master supply must always be the one at the positive end of the series combination The output voltage of each slave supply varies in direct proportion to that of the master and the ratio of each slave s output voltage to the master s is established by the settings of the slave supplies voltage controls The resulting combination of two or three supplies behaves as if it were a single constant voltage constant current supply The supply with the lowest current ra
16. lowa Continental Device Corp Hawthorne Calif Raytheon Co Components Div Mountain View Calif Breeze Corporations Inc Union N J Reliance Mica Corp Brooklyn N Y Sloan Company The Sun Valley Calif Products Co Inc Wyckoff N J General Elect Co Minature Lamp Dept Cleveland Ohio Nylomatic Corp Norrisville Pa RCH Supply Co Vernon Calif Airco Speer Electronic Components Bradford Pa Hewlett Packard Co New Jersey Div Rockaway N f General Elect Co Semiconductor Prod Dept Buffalo N Y General Elect Co Semiconductor Prod Dept Auburn N Y Newton Mass Norwalk Conn C amp K Components inc Burndy Corp Wagner Electric Corp Tung Sol Div CTS of Berne Inc Chicago Telephone of Cal Enc So Pasadena Calif Bloomfield N J Rerne IRC Div of TRW Inc Boone N C General Instrument Corp Newark N J Philadelphia Handle Co Camden N J U S Terminals Inc Cincinnati Ohio Hamlin Inc Lake Mills Wisconsin Clarostat Mfg Co Inc Dover N H Thermalloy Co Dailas Texas Hewlett Packard Co Corneil Dubilier Electronics Div Federal Pacific Electric Co Newark N J General Instrument Corp Semicon ductor Prod Group Hicksville N Y Fenwal Elect Framingham Mass Corning Glass Works Raleigh N C Loveland Colo 2 CODE 16758 17545 17803 17870 18324 19315 19701
17. performance check to verify proper instrument operation 2 7 INSTALLATION DATA 2 8 The instrument is shipped ready for permanent rack installation or bench operation It is necessary only to connect the instrument to a source of power and it is ready for use 2 9 Location and Cooling 2 10 The Model 62748 is fan cooled the other models are cooled by convection The Model 6274B must be installed with sufficient space for cooling air to reach the sides and rear of the instrument The other models require a free flow of air past the cooling fins on the rear panel only These power supplies should be used in an area where the ambient temperature does not exceed 55 C 2 11 Outline Diagram 2 12 Figure 2 1 shows the outline shape and dimensions of these supplies 2 13 Rack Mounting 2 14 This instrument is full rack size and can be easily 2 1 MOOELS 62568 62646 62678 62748 TERMINAL STRIP DETAIL 5740 SCREW CTR TO A2 3445 5 5 AS 5 REMOTE CURRENT T PROG Tom REMOTE VOLTAGE PROS OUTPUT 6 32 SCREW 8 ZEE ns CAPACITOR DISCONNECT FRONT PANEL DIMERSIONS 5 24 132 Sem HIGH 19 000 482 6 ma WIDE 0 190 4 THK REAR SIDE MODELS 62636 62658 62668 62714 TERMINAL STRIP DETAIL Tor 16 750 425 REMOTE VOLTAGE OUTPUT PROS TERS SCREW SIZE 5 40 TERM AS US
18. selected EB 01121 R20 fxd film 1k 1 1 4W 0 07716 0757 0338 R21 fxd comp 1k 5 1 2W EB 1025 01121 0686 1025 R24 6256B 64B 678 74B fxd ww 05 5 6W 28480 0811 3364 R25 fxd comp 360k 5 1 2W 3645 01121 0686 3645 R26 fxd film 1 5k 1 1 8W CEA 0 07716 0757 0427 R27 6256B 648 67B8 74B fxd ww 05 5 6W 28480 0811 3364 R28 fxd comp 560k 5 1 2W 5645 01121 0686 5645 R29 fxd film 7 5k 1 1 8W CEA 0 07716 0757 0440 230 ww 5k 110 F4 11236 2100 1824 R31 fxd comp 1k 5 1 2W 1025 01121 0686 1025 R32 fxd film 160k 1 1 8W CEA 0 07716 0698 5092 R33 62568 638 648 658 fxd comp 330 5 1 2W EB 3315 01121 0686 3315 66B 67B 71B 62748 fxd comp 24 5 1 2W EB 2405 01121 0686 2405 R34 fxd comp 33k 5 1 2W EB 3335 01121 0686 3335 R35 fxd film 1k 1 1 8W CEA 0 07716 0757 0280 R36 fxd film 1 5k 1 1 8W CEA 0 07716 0757 0427 R37 fxd film 560 1 1 4W CEB 0 07716 0698 5146 R38 fxd comp 10k 5 1 2W EB 1035 01121 0686 1035 R39 fxd comp 200k 5 1 2W 2045 01121 0686 2045 R41 fxd film 5 49k 1 1 8W CEA T 0 07716 0698 3382 R42 fxd met ox 180 5 2W RG42 11502 0698 3626 R43 fxd film 2k 1 1 4W CEA 0 07716 0757 0739 R44 fxd film 471 1 1 8W CEA 0 07716 0698 5514 R45 fxd comp 100k 5 1 2W 1045 01121 0686 1045 R46 fxd film 600 1 1 8W CEA 0 07716 0757 1100 R47 fxd fiim 7 5k 1 1 8W CEA 0 07716 0757 0440 R48 fxd film 499 1 1 4W CEB 0 07716 0698 32
19. 01 Vdc 542 Effect Load Regulation Definition The change in the static value of the dc output current resulting from a change in load resis tance from short circuit to a value which yields maximum rated output boltage or vice versa CURRENT SAMPLING TERMINALS TO UNGROUNCED Ry TERMINAL OF POWER SUPPLY TO GROUNDED TERMINAL OF POWER SUPPLY SAMPLING RESISTOR LOAD TERMINALS Figure 5 6 Current Sampling Resistor Connections 5 7 5 43 To check the constant current load effect proceed as follows a Connect test setup shown in Figure 5 7 b Turn VOLTAGE controls fully clockwise c Turn on supply and adjust CURRENT controls until front panel ammeter indicates exactiy maximum rated output current d Read and record voltage indicated on digital voitmeter e Short circuit load resistor f Digital voltmeter reading should not differ from reading recorded in step d by more than 62568 62648 113uV 6263 62678 125uV 6265 62718 184uV 62668 150 6274 116uV 5 44 Source Effect Line Regulation Definition The change the static value of output current resulting from a change ac input voltage over the specified range from low line to high tine or from high fine to low line 5 45 To check source effect proceed as follows a Connect test setup shown in Figure 5 7 b Connect variable autotransformer between input power source and power suppl
20. 1548 6256B 64B 678 74B barrier strip jumpers qty 6 0360 1143 6263B 65B 668 71B barrier strip jumpers qty 7 0360 1143 A2 Filter Ass y Mechanical heat sink 28480 5020 2281 heat sink mounting standoff 687 28480 0380 0625 qty 3 PC board mounting standoff 938 28480 0380 0576 4 washer fiber L1A L1B insulator 28480 3050 0697 5020 2283 cover standoff 312 qty 4 0380 0356 A3 Front Panel Ass y Mechanical 6256B 6263B 62648 62658 62668 62678 62718 62748 front panel front panel front panel front panel front panel front panel front panel front panel 06256 60006 06263 60004 06264 60006 06265 60004 06266 60004 06267 60006 06271 60004 06274 00014 6256B 63B 64B 65B fuseholder qty 2 1400 0084 66B 67B 71B 62568 638 648 658 668 678 718 2950 0131 hex nut nylon fuseholder qty 2 nearest commercial equivalent 6 13 6 4 Replaceable Parts REF DESIG MFG AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER 62568 638 648 658 lockwasher fuseholder qty 2 28480 2190 0054 668 678 718 62568 648 678 748 meter qty 2 4040 0293 62638 658 668 718 meter bezel qty 2 4040 0414 spring compression meter mount 8 1460 0256 knob qty 4 0370 0084 binding post black qty 2 DF21BC 1510 0039 binding post red
21. 2 2B Disconnect T1 input lead from terminal 5 and connect it to terminal 4 See Figure 2 2B f Model 6274B only Disconnect input lead from the 115 tap on bias transformer T2 and connect it instead to the 208V tap Leave cooling fan B1 connected to the 115 tap See Figure 2 38 f Models 6256B through 62718 only Remove the jumpers from bias transformer T2 that connect terminals 1 with 3 and 2 with 5 and install a jumper between terminals 2 See Figure 2 2B 9 Models 62568 through 62718 only Disconnect T2 input tead from terminal 5 and connect it to terminal 4 See Figure 2 2B h Models 62568 through 6271B only Replace bias fuse F2 with a 1 16 slo blo fuse HP Part No 2110 0311 i Models 6256B through 6271B oniy Replace line fuse F1 with a fuse of the rating listed below Model Rating HP Part No 6256B 5A 250V 2110 0227 6263B 6266B 62718 250 2110 0003 62648 62678 6A 250V 2110 0056 6265 2 250V 2110 0002 2 22 Converting A Standard Instrument 230 Volt Operation 2 23 Models 6256B Through 6271B To convert any of these models from 115 volt operation to 230 volt operation follow the instructions given in paragraph 2 21 but omit steps e and g Leave the input leads to T1 and T2 terminal 5 See Figure 2 2C 2 24 Model 6274B To convert the Model 6274B from 11 amp volt operation to 230 volt operation follow the instructions given in paragraph 2 21
22. 21520 22229 22753 23936 24446 24455 24655 24681 26982 27014 28480 28520 28875 31514 31827 3317 35434 37942 42190 43334 Table 6 3 Code List of Manufacturers MANUFACTURER ADDRESS Delco Radio Div of General Motors Corn Kokomo Ind Atlantic Semiconductors Inc Asbury Park N J Fairchitd Camera and Instrument Corp Mountain View Calif Daven Div Thomas A Edison Industries McGraw Edison Co Orange N J Signetics Corp Sunnyvale Calif Bendix Corp The Navigation and Control Div Teterboro N J Electra Midland Corp Mineral Wells Texas Fansteel Metallurgical Corp No Chicago Ill Union Carbide Corp Electronics Div Mountain View Calif UID Electronics Corp Fia Pamotor Inc Pampa Texas General ElectricCo Schenectady N Y Genera Electric Co Nela Park Cleveland Ohio General Radio Co West Concord Mass LTV Electrosystems Inc Memcor Com ponents Operations Huntington Ind Dynacool Mfg Co Inc Saugerties N Y National Semiconductor Corp Santa Clara Calif Hewlett Packard Co Palo Alto Calif Heyman Mfg Co Kenilworth N J IMC Magnetics Corp Rochester N H SAE Advance Packaging Inc Santa Ana Calif Ramona Calif Owensboro Ky Budwig Mfg Co G E Co Tube Dept Lectrohm Inc Chicago Mallory amp Co Indianapotis Ind Muter Co Chicago lil New Departure Hyatt Bearings Div Generai Motors Corp Sandusky
23. 5 5 anig 182 15 NO 4129 0 822 TION NI 15 82929 7300W LON blo A1NO 89229 73004 18 301981 Iv LICET Td m ASSY 148 eV 03374405 31 Ob 22 I2 02 HOl1dO 303 NIYII ONI2IAB3S 0 2 3 4 1 3 35I2H3X3 191143103 3ND 2v 38V 355 3H 27 JHA JO MNISJV3H NY ISYY AKL m mM m T eed x i j i 3 SCHEMATIC TABLE SaF 50 Saf SOV Sur 50 5 65 cs 200v 1 2007 900 200 2200 200 34OO0 amp F 5400027 50 400004 50 22000 F 75V 34000 30v 34000 50 NOT USED 22000 F 74V 22 F 35V 24F 35V SOV uF 100V c20 8600 F 25 8600 25V 2000 45 1S00uF 85 Ft 10 NOT USED Ri IK 5 IW 1K 5 3W IK 5 3W 2K 5 282 43 5 82 5 2 160 5 2w 240 5 1 29 R9 600 5 SW 600 5 54 600 55 5 IK 5 Sw RIO 2 5K 10K 20K RI 50 50 50 IK RI2 680 256 SW 680 5 5W 580 5 5 IK 5 SW RIS TSOK S LSM 5 1 2W 15M 5 1 24 3M 5 2W RIS 202 200 IK RI Jo 100 100 5 36 35 5 34 5 2W 14K 5 2 R33 330 554 1 2wW 330 594 2W 330 3 1 2W 24 59 1
24. 82877 82893 83058 83186 83298 83330 83385 83501 83508 83594 83835 83877 84171 84411 86664 86838 87034 87216 87585 87929 88140 88245 90634 90763 91345 91418 91506 91637 91662 91929 92825 93332 93410 94144 94154 94222 95263 95354 95712 95987 96791 97464 97702 98291 98410 98978 99934 MANUFACTURER ADDRESS Madison Wisc Woodstock N Y Glendale Calif Cambridge Mass Springfield N J Eatontown N J Brooklyn N Y Research Products Corn Rotron Inc Vector Electronic Co Carr Fastener Co Victory Engineering Bendix Corp Herman H Smith Inc Central Screw Co Chicago lil Gavitt Wire and Cable Brookfield Mass Grant Pulley and Hardware Co West Nyack N Y Burroughs Corp Plainfieid N J U S Radium Corp Morristown N J Yardeny Laboratories New York N Y Arco Electronics Inc Great Neck N Y TRW Capacitor Div Ogallata Neb RCA Corp Harrison N J Rummel Fibre Co Newark N J Marco amp Oak Industries Anaheim Calif Philco Corp Lansdale Pa Stockwell Rubber Co Tower Oischan Corp Bridgeport Conn Cutler Hammer Inc Lincoin Iti Litton Precision Products Inc USECO Van Nuys Calif Metuchen N J Chicago III Philadelphia Pa Gulton Industries Inc United Car Inc Miller Dial and Nameplate Co EI Monte Calif Radio Materiais Co Chicago HI Augat Inc Attleboro Mass D
25. C 9430
26. CASE OSCILLOSCOPE CASE GNO A INACCURATE METHOD USING SINGLE ENDED SCOPE GROUND CURRENT 16 PRODUCES 60 DROP IN NEGATIVE LEAD WHICH ADDS TO THE POWER SUPPLY RIPPLE DISPLAYED ON SCOPE POWER SUPPLY CASE OSCILLOSCOPE CASE smiecoeo LJ TWO wiRE X LENGTH OF LEAD BETWEEN Re AND GROUNDED OUTPUT TERMINAL OF POWER SUPPLY MUST BE HELO TO ABSOLUTE MINIMUM 8 RECOMMENDED METHOD USING A DIFFERENTIAL SCOPE WITH FLOATING INPUT GROUND CURRENT PATH IS BROKEN COMMON MODE REJECTION OF DIFFERENTIAL INPUT SCOPE IGNORES DIFFERENCE iN GROUND POTENTIAL OF POWER SUPPLY AND SCOPE AND SHIELDED TWO WIRE FURTHER REDUCES STRAY PICKUP ON SCOPE LEADS Figure 5 8 Constant Current Ripple and Noise Test Setup supply The presence of a 120Hz waveform on the oscillo scope norrnaiiy indicates a correct measurement method waveshape having 60Hz as its fundamental component usually indicates an incorrect measurement setup 5 48 To check the ripple and noise proceed as follows a Connect oscilloscope or rms voltmeter as shown in Figure 5 or 5 88 b Rotate VOLTAGE controls fully clockwise Turn on supply and adjust CURRENT controts until front panel ammeter reads exactly maximum rated output current d The observed ripple and noise should be less than 6256B 6264B 125uV rms 6263B 62678 150uV rms 6265B 62718 5O1uV rms 62668 300uV rms 62748 165uV rms 5 49 TROUBLESHOOTING 5 50 Before attempting to trou
27. CEA T 0 07716 0698 3440 R67 6256B 63B 64B fxd ww 150 596 10W 247E1515 56289 0811 1906 62658 fxd ww 600 5 10W 247E6015 56289 0811 1910 62668 678 fxd ww 400 5 10W 247E4015 56289 0811 0942 6271B 74B fxd ww 800 5 10W 10XM 63743 0811 0944 R68 fxd ww 220 5 2W BWH 07716 0811 1763 R69 fxd comp 22 5 1 2W EB 2205 01121 0686 2205 R70 fxd met ox 1 5k 5 2W C428 16299 0698 3338 R71 fxd comp 1 8k 5 1 2W EB 1825 01121 0686 1825 R72 fxd comp 9 1k 5 1 2W EB 9125 01121 0686 9125 R73 fxd comp 100k 5 1 2W EB 1045 01121 0686 1045 R74 62568 63 648 fxd comp 4 3k 5 1 2W EB 4325 01121 0686 4325 658 668 678 6271B fxd comp 6 8k 5 1 2W EB 6825 01121 0686 6825 6274B fxd comp 10k 5 1 2W EB 1035 01121 0686 1035 R75 var ww 5k 110 F4 11236 2100 1824 R76 6256B fxd comp 75k 595 1 2W EB 7535 01121 0686 7535 6263B fxd comp 160k 5 1 2W EB 1645 01121 0686 1645 6264B fxd comp 100k 5 1 2W EB 1045 01121 0686 1045 6265B 668 fxd comp 200k 596 1 2W EB 2045 01121 0686 2045 62678 fxd comp 390k 5 1 2W EB 3945 01121 0686 3945 6271B 74B fxd comp 300k 5 1 2W EB 3045 01121 0686 3045 R77 fxd comp 4 7 5 1 2W EB 47G5 01121 0698 0001 R78 fxd comp 510 5 1 2W _ EB 5115 01121 0686 5115 R79 62568 638 648 658 fxd comp 2 4k 5 1 2W EB 2425 01121 0686 2425 668 678 718 62748 fxd comp 5 1k 5 1 2W EB 5125 01121 0686 5125 R84 fxd comp 10 5 1 2W EB 1005 01121 0686 1005 6 8 LA REF DESIG MODELS R86 6256B
28. DF21RC 1510 0103 bushing R109 mount 1410 0052 retainer push on DS1 and DS2 0510 0123 aty 2 Rear Panei Ass y Mechanical See Note 3 6256B rear chassis 28480 06256 60005 62648 678 rear chassis 28480 06264 60005 62748 rear chassis 28480 06274 60010 heat sink 4 5 8 x 5 1 8 28480 5020 8066 heat sink 4 5 8 x 2 1 2 28480 5020 8071 TB3 barrier strip 3 term ac input 603 3 75382 0360 1596 insulator ac barrier strip qty 2 28480 0380 0703 TB2 barrier strip 6 term output 601 YSY 6 75382 0360 1224 jumper output barrier strip qty 3 i 28480 0360 1541 hex standoff 750 R54 2 28480 0380 0091 transistor insulator mica Q6 7 28480 0340 0181 2 62568 648 678 transistor insulator mica 28480 0340 0180 62748 transistor insulator mica 28480 0340 0703 transistor pin insulator Q6 7 28480 0340 0166 4 transistor screw insulator Q3 6 7 6 insulating bushing CR11 CR34 qty 3 insulator mica CR11 34 qty 2 28480 0340 0168 28480 28480 2190 0710 Chassis Mechanical chassis assembly includes left and right sides center tray and front pane supports chassis assembly includes left and right sides center tray and front panel supports printed circuit board guide qty 2 Covers top and bottom perforated aty 2 Covers top and bottom solid qty 2 62568 648 678 748 5060 7951
29. Ohio Ohmite Manufacturing Co Skokie Ill Penn Engr and Mfg Corp Doylestown Pa Polaroid Corp Cambridge Mass Raytheon Co Lexington Mass Simpson Electric Co Div of American Gage and Machine Co Chicago II Spraque Electric Co North Adams Mass Superior Electric Co Bristol Conn Syntron Div of FMC Corp Homer City Pa 6 3 59730 61637 63743 70563 70901 70903 71218 71279 71400 71450 71468 71590 71700 71707 71744 71785 71984 72136 72619 72699 72765 72962 72982 73096 73138 73168 73293 73445 73506 73559 73734 74193 74545 74868 74970 CODE MANUFACTURER ADDRESS Thomas and Betts Co Philadelphia Pa Union Carbide Corp New York Ward Leonard Electric Co Mt Vernon N Y Amperite Co Inc Union City N J Beemer Engrg Co Fort Washington Pa Belden Corp Chicago Ill Bud Radio Inc Willoughby Ohio Cambridge Thermionic Corp Cambridge Mass Bussmann Mfg Div of McGraw amp Edison Co St Louis Mo CTS Corp Elkhart Ind 1 Cannon Electric Inc Los Angeles Calif Globe Union Inc Milwaukee Wis General Cable Corp Cornish Wire Co Div Williamstown Mass Coto Coil Co Inc Providence 1 Chicago Miniature Lamp Works Chicago Cinch Mfg Co and Howard B Jones Div Chicago 111 Dow Corning Corp Midland Mich Electro Motive Mfg Co inc Wi
30. This enables one comparator or the other to take control 4 9 Figure 4 2 shows the output characteristic of a constant voltage constant current power supply With no load connected the output current our is Zero and the output voltage Eg equals the front panei voitage con trol setting Eg When a load resistance is connected to the output terminals of the supply the output current increases while the output voltage remains constant Point D thus represents a typical constant voltage operating point Further decreases in load resistance are accompanied by further increases in with no change in the output voltage until the output current reaches Is a value equal to the front pane current control setting At this point the supply automatically changes its mode of operation and becomes constant current source Still further decreases in the value of load resistance are accompanied by a drop in the supply s output voltage with no accompanying change in its output current With a short circuit across the load terminals lout ls and Eout 0 4 10 The crossover value of load resistance can be defined as Rc Eg ig Adjustment of the front panel voltage and current controls permits this crossover resistance Rc to be set to any desired value from 0 to if is greater than Re the supply is in constant voltage operation if Re is less than the supply is in constant current operation 4 11 The short ci
31. UNLESS OTHERWISE NOTED D VOLTAGES ARE TYPICAL 510 UNLESS OTHERWISE NOTED ALL READINGS TAKEN IN CONSTANT VOLTAGE OPERATION AT MAXIMUM RATED OUTPUT WITH NO LOAD CONNECTED ANO CURRENT CONTROLS TURNEO FULLY CLOCKWISE ALL COMPONENTS LOCATED ON MAIN PRINTED CIRCUIT BOARD UNLESS OTHERWISE INDICATED DENOTES CHASSIS MOUNTED COMPONENTS PIN LOCATIONS FOR INTEGRAT D CIRCUITS ARE AS FOLLOWS TOP VIEWS PIN LOCATIONS FOR SEMICONDUCTORS ARE AS FOLLOWS TERMINAL CATHOOE et A 70 5 Pts 430 ATED anog 9 3 TO 56 TOP VIEWS c TRIAC SCR VIEWS TOP VIEW ACRI JUMPERS 7 8 48 REMOVED WHEN SUPPLY iS EQUIPPED WITH OPTION 020 922 OR 040 JUMPERS 45 JG REMOVED WHEN SUPPLY 15 EQUIPPED WITH OPTION 021 022 OR 940 FOR 5 INPUT CONNECT JUMPERS JI 12 ANO 44 AND DISCONNECT J3 FOR 208 OR 3OVAC INPUT CONNECT J3 AND DISCONNECT Ji J2 AND 24 SEE FIGURE 4 4 FOR PREREGULATOR CONTROL CIRCUIT WAVEFORMS MODELS 62568 REFERENCE Cif MODEL 62748 ONL 52648 52678 ONLY o SOME CIRCUITS IN THIS POWER SUPPLY ARE CONNECTED DIRECTLY TO THE INPUT AC LINE THE CASE HEATSINK THE A2 RFI ASSEMBLY ARE ALSO LINE POTENTIAL EXERCISE EXTREME CAUTION WHEN WORKING ON ENERGIZED CIRCUITS MARE ANARIN ANANI 1
32. adjustments that affect the operation of the faulty circuit 5 64 Meter Zero Adjustment 5 65 The meter pointer must rest the zero calibration mark on the meter scale when the instrument is at normal operating temperature resting in its normal operating position and turned off To zero the meter proceed as follows a Turn on instrument and allow it to come up to normal operating temperature about 30 minutes b Turn instrument off and wait two minutes for power supply capacitors to discharge completely Insert pointed object pen point awl into small indentation near top of round black plastic disc located directly below meter face d Rotate plastic disc clockwise until meter reads Zero then rotate counterclockwise slightly in order to free adjustment screw from meter suspension Pointer should not move during latter part of adjustment 5 66 ee me elit na a dan zx VULUTICLOED 5 67 To calibrate the voltmeter proceed as follows a Connect digital voltmeter across plus and minus output terminals of supply observing correct polarity b Turn on supply and adjust VOLTAGE controls until digital voltmeter reads exactly the maximum rated output voltage c Adjust R56 until front panel voltmeter also indicates exactly the maximum rated output voltage 5 68 Ammeter Calibration 5 69 To calibrate the ammeter proceed as follows a Connect test setup shown in Figure 5 7 b Turn VOLTAG
33. but their current controls remain operative and must be set to maximur to prevent a slave supply from independently reverting to constant current operation as would occur if the output current setting of the master suppiy exceeded that of a slave 3 46 Overvoltage Protection in Auto Parallel The interconnections shown in Figures 3 8 and 3 9 between transformer T4 in the master and T4 in the slave s must be made to permit the overvoltage crowbar in the master to fire the SCRs in the master and the slave s if an over voltage condition occurs The circuit board pads to be interconnected are marked EXT TRIG and their locations are indicated on the component location di grams MODELS 62568 62648 62678 62748 Al A2 A4 5 AG 7 A9 5 T MODEL Ry 62568 62648 130 Rx 6267B 62748 1 5K AB MODELS 62638 62658 62668 627 8 A2 A4 A5 AT 5 GNDAB 5 Figure 3 7 Voltage Programming of Output Current in Section Be sure to connect them with correct polarity terminal 5 to 5 and 6 to 6 Set the slave supply overvoitage potentiometer s to maximum ciockwise disable them and adjust the overvoltage trip point at the master supply 3 47 Auto Parallel With Remote Sensing To combine auto parallel operation with remote sensing connect the supplies as described above but remove the S and S jumpers from the master supply and connect the
34. comparator circuit The voltage clamp eliminates this undesirable effect by maintaining the programming current at a constant level 4 44 The voitage divider consisting of 22 Z2B and VR3 back biases CR30 and Q10 during constant voltage operation When the power supply goes into constant current operation CR30 becomes forward biased by the voltage at pin 12 of Z1 This resuits in conduction of Q10 and the clamping of the summing point at a potential only slightly more negative than the normal constant voltage potential Clamping this voltage at approximately the same potential that exists in constant voltage operation results in a constant voltage across and consequently a constant current through current puliout resistors R9 R12 and R13 4 45 Mixer and Error Amplifiers 4 46 The mixer and error amplifiers amplify the error signal received from the constant voltage or constant current input circuit to a level sufficient to drive the series regulator transistors Mixer amplifier Q5 receives the error voltage input from either the constant voltage or constant current comparator via the OR gate diode CR3 or CR4 that is conducting at the time Diode is forward biased and 4 reverse biased during constant voltage operation The reverse is true during constant current operation 4 47 Transistor Q11 provides a constant current to the collector of Q5 and also generates a negative going turn off signal for the series reg
35. do open the supply s output current rises to a value thay may damage the supply the load If in the particular programming configuration used there is a chance that the terminals might open we suggest that a resistor of the foilowing value be connected across the programming terminals Models 62568 62648 200 ohms 6263B 6266B 1000 ohms 62678 6274B8 1000 ohms 62658 62718 900 ohms Of course when this resistor is used the resistance value actually programming the supply is the parallel combination of the remote programming resistance and the resistor across the programming terminals Like the programming resistor this resistor should be a low noise low temperature coefficient type 3 42 Constant Current Output Voltage Input The rear panel connections shown in Figure 3 7 allow the output current to be varied by using an external voltage source to program the supply The constant current programming MODELS 62568 62648 62678 62748 2 4 AS AG S A9 AIO 5 lt 9021210010101012 PROGRAMMING RESISTOR AB GNO MODELS 62638 62658 62665 627 8 Al A2 A4 AS AG AT S 5 PROGRAMMING RESISTOR Figure 3 6 Resistance Programming of Output Current coefficients for the supplies included in this manual are as follows 1096 Models 62568 6264B 25mV ampere 6263B 6267B 6265 62718 167mV ampere 62668 100mV ampere 6274B 33 3mV ampere T
36. is greater than 25 turn off supply and replace R78 with decade resistance g Turn on supply and adjust decade resistance to reduce imbalance to within 2596 n Vary input line voltage from 104 to 127 Vac and insure that excessive imbalance does not exist anywhere within this range 5 86 Preregulator Tracking Adjustment 5 87 To adjust the voltage drop across the series regulator proceed as follows a Connect load resistor specified in Figure 5 1 across rear output terminals of supply b Connect variable autotransformer between input power source and power supply input and adiust it for a 115 input to the supply c Connect dc voltmeter across series regulator between TP47 and TP81 2 8 Turn CURRENT controls fully clockwise e To check voltage drop across regulator at low output voltage short circuit the load resistor and adjust VOLTAGE controls for maximum rated output current on front pane ammeter f Adjust R75 RAMP AD until voltmeter reads 3 7Vdc g To check the voltage drop at high output voltage remove short circuit from across load resistor and adjust VOLTAGE controls for maximum rated output current Voltmeter reading should again be 3 7N dc h Vary input line voltage from 104 to 127Vac Volt meter reading should vary between 3 1 and 4 3Vdc if reading exceeds this range proceed to step i i Replace R76 with decade box Vary input line voltage between 104 and 127 Vac and adjust decade box u
37. one of the slaves crowbars no other supply is affected 3 65 In order to have all supplies in an auto tracking combination crowbar simultaneously if any of them has an overvoltage condition parallel their crowbar circuits as shown in Figure 3 10 or 3 11 and described in paragraph 3 56 MODELS 62568 62648 62678 62748 Al A2 4 5 AT S AID 5 219901219990 AS GNO MODELS 62638 62658 62668 627 8 Al 5 4 A5 GNDAB S MASTER Miu Figure 3 12 Auto Tracking Operation of Two Units MODELS 62568 62548 62678 62748 Al 2 A3 A4 5 S A9 5 491901269412 5 NO 1 MODELS 62638 52658 62668 62718 Al 2285 25 5 S PA A Rx Al 42 4 AS EA 4 5 AG AT S 292012904100 oleo ide Figure 3 13 Auto Tracking Operation of Three Units 3 13 3 66 Auto Tracking With Remote Sensing To combine auto tracking operation with remote sensing connect the Supplies as described above but remove the 5 and 5 jumpers from each supply and connect the S and 5 terminals directly to the and ends of its load Observe the precautions outlined under paragraph 3 25 3 67 Auto Tracking With Remote Programming When two or three supplies are connected for auto tracking opera tion their output voltages
38. or negative output terminal of a supply may be grounded or the 5 output may be floated at up to 300 volts above ground 1 7 Remote programming remote sensing and several methods of operating supplies in combinations of two or three are made possible by rear panel terminals that allow access to contro points within the regulator circuits These capabilities are described below a Remote Programming The power supply s output voltage or current or both can be controlled from a remote location by varying a resistance or a voltage input signal to the supply s voltage or current regulator circuit b Remote Sensing Connecting the voltage regulator s feedback circuit to the load terminals rather than to the supply s output terminals prevents the voltage drop in the load leads from impairing voltage regulation at the load when operating in the constant voltage mode A separate pair of sensing leads which carry no load current extend the feedback loop to the load terminals Operation Two or three similar supplies connected in parallel can be made to share loads equally and can be controlled by the voltage and current controls or remote programming terminals of one of the supplies designated the master if they are connected for auto parallel operation Normally only supplies having the same mode number are connected in but auto parallel operation can be used with any of the sup
39. power source If the correct result is not obtained fora particular check do not adjust any internal controls instead proceed to troubleshooting paragraph 5 49 5 7 CONSTANT VOLTAGE TESTS 5 8 Connect all of the measuring devices used in the constant voltage performance tests directly to the power supply sensing terminals 5 For best accuracy the sensing terminals must be used rather than the output terminals since the measuring instruments must be connected to the same pair of terminals to which the feedback amplifier within the power supply is connected This is particularly important when measuring the regula tion transient response or ripple of the power supply Note that the measuring instruments should not be connected across the load A measurement made across the load includes the impedance of the leads to the load and such lead lengths can easily have an impedance several orders of magnitude greater than the supply impedance typically 1 milliohm at dc thus invalidating the measurement 5 9 To avoid mutual coupling effects connect each monitoring device to the sensing terminals by a separate pair of leads Use twisted pairs or shielded two wire cables to avoid pickup on the measuring leads Connect the load resistor across the output terminals as close to the supply as possible When measuring the constant voltage performance specifications set the current controls well above at Jeast 10 above the maximum output cur
40. supply CAUTION Any time these supplies are used to charge battery be sure to install a protective diode CR P in series with the battery as shown in in Figure 3 14 to prevent the battery from discharging into the supply if the supply is turned off Extensive darnage to the supply could result if this diode were omitted The use of remote voltage sensing provides no advantages when performing a constant current battery charge as discussed in paragraph 3 81 or a taper charge as discussed in paragraph 3 82 Because of a serious risk of damage to the supply the use of remote voltage sensing should not be attempted when charging or discharging a battery Aiso see the CAUTION following paragraph 3 30 NOTE A large battery connected as load presents a large capacitance to the output terminals This capacitance could cause the supply to oscillate If the supply appears unstable it may be beneficial to readjust transient recovery contro R30 located on the main circuit board 3 81 Constant Current Charge To perform a constant current battery charge set the charging rate and full charge voltage as follows a Turn both the VOLTAGE and CURRENT controls fully counterclockwise CCW b Connect a short circuit across the output terminals and rotate the VOLTAGE control fully clockwise CW Adjust the CURRENT control for the desired charging rate as read on the front panel ammeter d Rotate VOL
41. supply appears unstable it may be beneficial to readjust transient recovery contro R30 located on the main circuit board 3 73 It may also be desirable to remove C20 from the circuit when the supply is being used in the constant current mode for the following reasons a With C20 connected the output impedance of the supply decreases with increasing frequency b With C20 connected the output current takes longer tm uw ih With C20 connected a rapid reduction in load resis tance can produce a large surge current that could cause high power dissipation in the load 3 74 Reverse Voltage Protection 3 75 An interna diode CR34 connected with reverse polarity across the output terminals of the supply protects the output electrolytic capacitors and series transistors from the effects of a reverse voltage applied across the supply s output Such a reverse voltage might inadvertently be applied when operating supplies in series if one of them were to be turned on or off before the other The current rating of CR34 is equal to the rated output current of the supply 3 76 The series regulator transistors are also protected against reverse voltage by diode CR11 This diode shunts the series regulators if the supply is connected in parallel with another supply but is deenergized 3 77 Reverse Current Loading 3 78 An active load connected to the power supply may actually deliver a reverse current to
42. the like which if not correctly per formed or adhered to could result in personal injury Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met The CAUTION sign denotes a hazard It calls attention to an operating pro cedure or the like which if not correct ly performed or adhered to could result in damage to or destruction of part or ali of the product Do not proceed beyond a CAUTION sign until the indicated lt 90 ditions are fully understood and met i ci p DO NOT SUBSTITUTE PARTS OR MODIFY INSTRUMENT 2d Because of the danger of introducing additional hazards do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to Hewlett Packard Sales and Service Office for service and repair to ensure that safety features are maintained d 1 Instruments which appear damaged or defective should be made inoperative and secured against unintended operation uni they can be repaired by qualified service personnel 5950 1826 s k ACOUSTIC NOISE INFORMATION The products included in this manual have been tested in accordance with German acoustic noise specification 3 GSGV The results of these tests are listed below M HP Models 62568 6263 6267 62718 ACOUSTIC NOISE EMISSION GERAeUSCHEMISSION LpA 70 dB LpA 70 dB o
43. the output of the master supply To do this make a direct connection from the S terminal of the master to the A2 terminal of the slave instead of using a programming resistor and remove the slave s A1 to A2 jumper 3 63 Setting the Voltage and Current Controls The voit age control of each slave must be set fully clockwise to obtain the voltage ratios established by the formula for Ry given in paragraph 3 61 By lowering the settings of the slave s voltage controls the voltage of the slave be made a smaller percentage of the master supply s voltage The current controls of all supplies in an auto tracking com bination are independently operative and can be used to set current limits for each individual load If the master supply goes into constant current mode the output voltages of the slaves continue to track that of the master 1f a slave supply goes into constant current mode however no other 3 12 supply is affected 3 64 Overvoitage Protection Auto Tracking Paraiiei ing the crowbar circuits as is required for the auto paratlel and auto series modes is optional in the auto tracking mode If the external trigger windings of transformer 4 in the master and in the slave supplies are not paralieled the overvoltage protection circuit in each supply indepen dently monitors the voltage across its own load Then if the master supply crowbars the output voltage of the slave s also decreases but if
44. the rear panel allow the voltage programming coefficient and zero output voltage to be adjusted conveniently to an accuracy of 0 1 Adjustable Current Programming Two screwdriver adjustable controls mounted on the rear panel allow the current programming coefficient and zero output current to be adjusted conveniently to an accuracy of 0 1 Adjustable Voltage and Current Programming This option includes Options 020 and 021 in the same instrument Rewiring for 208Vac 10 Single phase Input This factory modification reconnects the input transformers and the preregulator choke and replaces the fuses and the pilot light resistor for 208Vac operation 028 Rewiring 230 10 Single phase Input This factory modification reconnects 5 the input transformers and the prerequlator choke and replaces the fuses and the pilot light resistor for 230Vac operation Interfacing for Multiprogrammer Operation This factory modification prepares standard power supplies for resistance programming by the 69408 Multiprogrammer or the 69418 Multiprogrammer Extender Opera tion with either of these instruments requires that the power supply be subjected to a special calibration and a protection check out The special calibration insures that the power supply can be accurately set to zero and to the maximum rated output voltage or current when programmed by the muitiprogrammer The protection checkout insures th
45. the two inputs of the differential amplifier This difference voltage is amplified and appears at the output of the differential amplifier pin 6 as an error voltage which ultimately varies the conduction of the series regulator 4 41 Resistor R19 serves as a trimming adjustment for the programming current flowing through R16 and R17 If the supply is equipped with Option 021 or 040 resistor R125 and potentiometer R126 allow the programming current to be adjusted over a narrow range around its nominal value and resistor R127 and potentiometer R128 provide a variable input bias to allow the output current to be easily adjusted to exactly zero when the supply is programmed for zero output Diode limits excessive voltage excursions at the summing point input to the differential amplifier 4 42 Voltage Clamp Circuit 4 43 The voltage clamp circuit keeps the constant volt age programming current relatively constant when the power supply 15 operating in the constant current mode This is accomplished by clamping terminal A2 the voltage summing point to a fixed bias voltage During constant current operation the constant voltage progarmming resistors are a shunt load across the output terminals of the supply When the output voltage changes the current through these resistors also tends to change Since this programming current flows through the current sampling resistor it is erroneously interpreted as a load change by the current
46. 0686 2045 6265 fxd comp 300k 5 1 2W EB 3045 01121 0686 3045 6267B fxd comp 750k 596 1 2W EB 7545 01121 0686 7545 62718 fxd comp 360k 5 1 2W 3645 01121 0686 3645 62748 fxd comp 430k 5 1 2W EB 4345 01121 0686 4345 R78 6256B fxd comp 750 596 1 2W EB 7515 01121 0686 7515 6263B 64B 65B 66B fxd comp 270 5 1 2W EB 2715 01121 0686 2715 678 718 748 R79 6263 64 65 66 fxd comp 4 7k 5 1 2W EB 4725 01121 0686 4725 67 71 007 10 Turn Voltage Control R10 62568 var ww 2k 10 turn Series 8400 84048 2100 2029 6263B 64B var ww 5k 10 turn Series 8400 84048 2100 1865 6265B 66B 67B var ww 10k 10 turn Series 8400 84048 2100 1866 6271B 74B var ww 20k 10 turn Series 8400 84048 2100 1867 knob 28480 0370 0137 OPTION 008 10 Current Control 816 6256B 64B var ww 200 10 turn Series 8400 84048 2100 1863 62638 658 668 678 var ww 1k 10 turn Series 8400 84048 2100 1864 71B 74B knob 28480 0370 0137 OPTION 009 10 Turn Voltage and Current Controls R10 voltage control 62568 var ww 2k 10 turn Series 8400 2100 2029 6263B 648 var ww 5k 10 turn Series 8400 2100 1865 62658 668 678 ww 10k 10 turn Series 8400 2100 1866 6271B 74B var ww 20k 10 turn Series 8400 2100 1867 R16 current control 6256B 64B var ww 200 10 turn Series 8400 2100 1863 6263B 65B 66B 67B 71B 74B var ww Tk 10 turn knob 2 Series 8400 2100 1864 0370 0137
47. 07 R49 6256B fxd film 6k 1 1 8W CEA 0 07716 0698 3476 62638 64B fxd film 12k 1 1 8W CEA T 0 07716 0698 5088 62658 668 67B fxd film 27 4k 1 1 8W CEA 0 07716 0757 0452 6271B 74B fxd film 39k 1 1 8W CEA T 0 07716 0698 6076 R50 fxd comp 390 596 1 2W EB 3915 01121 0686 3915 R51 fxd fiim 3 4k 1 1 8W CEA 0 07716 0698 4440 R53 fxd comp 10 5 1 2W EB 1005 01121 0686 1005 R56 var ww 250 110 F4 11236 2100 0439 R57 6256B 63B 64B fxd film 471 1 1 8W CEA 07716 0698 5514 62658 658 668 fxd film 600 1 1 8W CEA T 0 07716 0757 1100 718 74B R58 59 fxd comp 100 5 1 2W EB 1015 01121 0686 1015 R60 fxd comp 3k 5 1 2W EB 3025 01121 0686 3025 Table 6 4 Replaceable Parts REF DESIG MFG HP AND MODELS DESCRIPTION PART NUMBER PART NUMBER R61 62568 648 678 fxd ww 135 5 3W 242E 56289 0812 0112 71B 74B 62638 658 668 fxd ww 390 5 3W 242E3915 56289 0811 1799 R62 fxd film 471 1 1 8W CEA 0 07716 0698 5514 R63 var ww 250 110 F4 11236 2100 0439 R64 6256B 638 648 65B fxd film 7 5k 1 1 8W CEA 0 07716 0757 0440 668 678 718 62748 fxd film 160k 1 1 8W CEA 993 07716 0698 5092 R65 62568 63B 64B 65B fxd film 5 49k 1 1 8W CEA 0 07716 0698 3382 668 678 718 62748 fxd film 91k 1 1 8W CEA 993 07716 0698 6080 R66 62568 648 fxd film 21 5 1 1 8W CEA T 0 07716 0698 3430 6263B 67B 74B fxd film 100 1 1 8W CEA T 0 07716 0757 0401 6265B 66B 71B fxd film 196 196 1 8W
48. 1 bus bar for C13 14 qty 2 28480 5000 6038 6274B fan spacer 28480 06274 00010 6263B 66B insulator mica CR11 34 2 28480 2190 0710 62638 668 insulating bushing CR11 34 2 28480 0340 0169 62568 638 648 insulator mica CR21 24 4 28480 2190 0710 67B 74B 62568 638 648 shoulder washer CR21 24 qty 4 28480 2190 0898 67B 74B 62668 insulator mica CR21 24 qty 4 28480 2190 0498 6266B shoulder washer CR21 24 qty 4 28480 2190 0492 62638 668 718 transistor screw insulator qty 2 28480 0340 0168 6263B 66B 71B insulating bushing Q3 28480 0340 0169 62638 668 transistor insulator mica 28480 0340 0180 62718 transistor insulator mica 28480 0340 0703 62638 658 668 718 transistor pin insulator qty 2 28480 0340 0166 6263B 65B 66B 71B transistor screw insulator Q6 aty 2 28480 0340 0168 62638 658 668 718 transistor insulator mica Q6 28480 0340 0181 6256B 64B 67B 74B carton 9211 1178 6256B 648 678 74B floater 9220 1401 62638 658 668 718 carton 9211 1176 6263B 65B 66B 71B floater 9220 1400 6 15 Table 6 4 Replaceable Parts D MFG HP AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER OPTIONS OPTION 005 50Hz AC Input R74 62668 fxd comp 8 2k 596 1 2W EB 8225 01121 0686 8225 R76 6256B 66B fxd comp 150k 5 1 2W EB 1545 01121 0686 1545 62638 648 fxd comp 200k 5 1 2W EB 2045 01121
49. 154 0160 0161 0180 0100 0180 1852 0150 0052 0180 0332 0180 0291 0180 0301 0160 2453 0180 0160 0180 1834 0180 0091 0180 0049 0160 0174 0150 0081 0160 0710 0160 0174 0160 0157 1901 0033 1901 0460 1901 0033 1901 0327 1901 0416 1901 0327 1901 0033 1901 0416 1901 0033 1901 0416 1901 0460 1901 0033 1901 0461 1901 0317 Note 1 This assembly is designed for component level repair replacement assemblies cannot be supplied 6 5 _ DESIG LEV AND MODELS CR57 CR58 60 Q3 6265B Q4 Q5 09 010 011 012 013 16 018 019 022 23 024 025 R1 62568 638 648 658 668 678 62718 748 82 62568 62638 648 62658 668 678 62718 748 R5 7 86 87 R8 R9 62568 638 648 658 668 678 62718 748 R12 62568 638 648 658 668 678 62718 748 813 R14 R15 62568 638 718 6264B 67B 6265 6266 62748 R18 62568 648 62638 658 668 678 71B 74B nearest commercial equivalent Table 6 4 Repiaceable Parts DESCRIPTION SCR diode Si 180V 200mA SS NPN Si SS PNP Si SS PNP Si SS PNP Si SS PNP Si SS NPN Si SS PNP Si SS NPN Si SS NPN Si SS NPN Si SS PNP Si SS NPN Si SS NPN Si fxd ww 1k 5 3W fxd ww 2k 5 3W fxd comp 43 5 1 2W fxd comp 82 5 1 2W fxd comp 160 5 1 2W fxd comp 240 5 1 2W fxd film 1 5k 1 1 8W fxd comp 360k 596 1 2W fxd film 61 9k 196 1 8W fxd comp 560k 596 1 2W
50. 2 VOLTMETER ADJ R33 RT 1 VRA 330 12V SEN as i REZ UNREG 560 SEE Vw 6 2V TABLE 200 124 SERIES REGULATOR ERROR MIXER 8 DRIVER AMPLIFIER AMPLIFIER METER CIRCUIT Rag SEE 355 TABLE D FROM CURRENT SAMPLING RESISTOR p FROM CURRENT SAMPLING RESISTOR FROM WT i t amp tt 412 ay 12 4 mg 220 225 13K 20K 4D 4 PO ZI EL L 1 i 12 44v BE ug lo 722 20 leet 0 2 15 50 1 EM 130 c 85 zen 5 CONSTANT 6 ov 62V THE CASE AND HEATSINK OF THE 2 ASSEMBLY ARE AT AC LINE POTENTIAL EXERCISE EXTREME CAUTION DURING SERVICING MTD ONAL CIRCUIT BOARD FOR 80 gt OPTION 20 21 22 OR 40 MODELS 62658 IF SUPPLIED 62718 di BOARD A2 Ra asy ELE RENS AARCRI INSIDE a REO gee ee 3 t 1 at d V 4 Spat whe eg is Me Figure 7 8 Chassis Component Locations for Models 62038 62658 62668 and 6271B mR d Bares ae TN HP Sales and lastrimper Deparment zm 818 505 102015 South Park Place LET Atlanta GA 30839 EE 404 955 1500 e Blackburn 4 Victorie 3130 Melboume Austral
51. 2 fxd elect 20uF 50V C27 62568 648 67 8 748 fxd cer 0 47uF 25V 28 62638 658 668 718 fxd cer O1u F 500V C29 62638 658 668 718 fxd polyester 0 1uF 600V fxd 0 47uF 25V C34 fxd polyester 4700pF 200V CR1 7 diode Si 180V 200mA CR8 diode 3 junction CR9 diode Si 180V 200mA CR10 diode Si 200V 1A CR11 6265B 71B diode Si 200V 1 5A 12 15 diode Si 200 1A CR16 20 diode Si 180V 200 CR21 24 62658 71B diode Si 200V 1 5A CR27 28 30 33 diode Si 180V 200mA CR34 62658 71B diode Si 200V 1 5A CR36 diode Si 3 junction CR37 38 43 47 50 diode Si 180V 200mA CR51 52 diode Si 10V 200mA CR56 diode Si 100V 40A MFG PART NUMBER 3005056050882 D33689 DSM 192P10492 192P10292 292P22292 192P10392 150D475X9035B2 33617A D34656 DEE 150D105X9035A2 3005056050882 1922224988 150D226X0035R2 150D156X0050R2 30D106G100DC2 30D206G050C02 501187 811 000 Y5U 0 1032 6630W10496W 5C11B7 CML 292P47292 1 485 STB 523 1 485 1 5059 1 4999 1 5059 1 485 1 4999 1 485 1 4999 5 523 1N485 SG9309 1N1184A MFG 56289 HP PART NUMBER 0180 0301 56289 56289 56289 56289 56289 56289 28480 56289 56289 56289 56289 56289 56289 56289 56289 56289 56289 72982 84411 56289 56289 03508 03508 03877 05277 nn A eee 0180 1836 0160 0168 0160 0153 0160 0
52. 48 62678 or 62748 power supplies t is recommend ed that the user supplied power cable have three conductors with the third conductor grounded and be of adequate wire size to handle the input current drawn by the supply see paragraph 2 15 Note that when the supply is operated from 208 volt or 230 volt source the input current is approximately half that shown in paragraph 2 15 2 31 REPACKAGING FOR SHIPMENT 2 32 To insure safe shipment of the instrument it is recommended that the package designed tor the instrument be used The original packaging material is reusable lf it is not available contact your local Hewlett Packard field office to obtain the materials This office will also furnish the address of the nearest service 24 office to which the instrument can be shipped and provide the Authorized Return label necessary to expedite the _ handling of your instrument return Be sure to attach a tag to the instrument which specifies the owner mode number full serial number and service required or a brief description of the trouble OPTION 900 OPTION 90 CPTION 902 OPTION 903 8120 1351 8120 1569 8120 1691 8120 0050 PART NO FOR PERMANENTLY ATTACHED LINE Figure 2 4 Power Cord Configurations P SECTION ill OPERATING INSTRUCTIONS MODEL MODELS 62568 62638 6264 6274B ONLY 6265B 6266B 62678 62718 Figure 3 1 Front Panel Controls and Indicators 3 1 TURN ON CHECKOUT PRO
53. 5k CT 100 4 2100 0896 022 Adjustable Voltage and Current Programming fxd film 221k 196 1 8W 0757 0473 var ww 15k 2100 0896 fxd film 249k 1 1 8W 0757 0270 var ww 15k 2100 0896 6 17 SOME CIRCUITS THIS CIRCUIT BD ARE CONNECTED DIRECTLY TO THE AC POWER LINE EXERCISE EXTREME CAUTION WHEN WORKING ON ENERGIZED CKTS PREREGULATOR CONTROL CIRCUIT TURN ON CONTROL OVERVOLTAGE PROTECTION CROWBAR EXT I T4 5 TRIG 4 6 MIXER amp ERROR AMPLIFIER RE FERENCE CIRCUIT 8888 97 ZERO bold wh Je CONS TANT os eee LH VOLTAGE COMP Figure 7 3 A1 Board Component Locations for Models 6256B 6264B 6267B and 6274B LOCATED HERE IN MODELS 62658 AND 62718 ONLY SOME CIRCUITS ON THIS CIRCUIT BOARD ARE CONNECTED a DIRECTLY TO THE wae INPUT AC POWER MODELS LINE EXERCISE DR we 62868 ONLY EXTREME CAUTION WHEN WORKING ON ENERGISED CIRCUITS Bh PREREGULATOR CONTROL CIRCUIT ENS TURN ON CONTROL OVERVOLTAGE PROTECTION CROWBAR EXT T4 5 TRIG T4 6 MI XER AND ERROR AMPLIFIER REFERENCE CIRCUIT M sich ee exes lz ZERO ry L cpu ADJ Figure 7 6 A1 Board Component Locations for Models 6263B 6265B 6266B and 6271B Pam SET f yyy ed 774 393 89129 pue 81929 87929 89229
54. 6289 56289 56289 56289 56289 56289 56289 56289 56289 56289 05277 05277 02735 05277 02735 05277 02735 05277 02735 02735 1854 0225 1854 0458 06264 80001 05267 80001 5080 7105 3160 0056 0180 1930 0180 1931 0180 1929 0180 1930 0180 1931 0180 1928 0180 1929 0180 1882 0180 2098 0180 1920 0180 1919 0180 1986 0150 0052 1901 0317 1901 0318 1901 0002 1901 0317 1901 0002 1901 0318 1901 0002 1901 0317 1854 0224 1854 0464 Table 6 4 Replaceable Parts REF DESIG MFG AND MODELS DESCRIPTION PART NUMBER CODE PART NUMBER Q6 6263B 66B power NPN Si 2N3771 1854 0245 6265B power NPN Si 2N3772 1854 0225 6271 power NPN Si 60675 02735 1854 0458 R54 current sampling resistor 6263B fxd low t c alloy 0 050 ohms 28480 06263 80001 6265B 71B fxd low t alloy 0 167 ohms 28480 5080 7125 6266B fxd low t c alloy 0 100 ohms 28480 06266 80001 T1 6256B power transformer 28480 06256 80091 6263B power transformer 28480 06263 80091 6264B power transformer 28480 06264 80091 6265B power transformer 28480 06265 80091 62668 power transformer 28480 06266 80091 62678 power transformer 28480 06267 80091 6271 power transformer 28480 06271 80091 6274B power transformer 28480 06274 80091 A1 Main PC Board Mechanical TB1 62568 64B 678 74B barrier strip 11 terminal 0360 1238 62638 658 66B 718 barrier strip 15 terminal 0360
55. 645 3325 6225 1845 1535 1035 C428 BWH C428 C428 425 5125 2715 1525 1015 EB 3015 GB 2015 CWS 2 EB 2045 RS 5 EB 1005 CEB T 0 CEB T 0 EB 5115 CEA T 0 CEB T 0 CEB T 0 1035 EB 47G5 EB 3925 993 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 16299 07716 16299 16299 16299 01121 01121 01121 01121 01121 01121 91637 01121 1627 01121 07716 07716 01121 07716 07716 07716 01121 01121 01121 07716 28480 28480 ne PART NUMBER 0686 5135 0686 1045 0686 2045 0686 3045 0686 3645 0686 3325 0686 6225 0686 1845 0686 1535 0686 1035 0698 3629 0811 2114 0698 3338 0764 0016 0764 0015 0686 5125 0686 2715 0686 1525 0686 1015 0686 3015 0689 2015 0811 1846 0686 2045 0812 0098 0686 1005 0698 3506 0698 3134 0686 5115 0757 0427 0698 3134 0757 0739 0686 1035 0698 0001 0686 3925 0758 0005 9100 2193 5080 7152 aanry m M essem a dium F AND MODELS T3 4 VR1 2 VR3 4 VR5 VR6 7 21 22 1 C3 C4 CRI 6256B 64B 67B 74B 62638 658 668 718 1 2 4 L1A L18 R1 R2 6256B 64B 67B 74B 62638 65B 668 71B R3 RV1 C1 3 62638 658 668 718 28 30 62568 648 678 748 1 62748 DS1 DS2 F1 6256B 6263B 66B 718 6264B 67B 6265B F2 62568 638 648 658 668 67
56. 7 63Hz for the standard models For other input voltages or 50Hz operation see the option listings in paragraph 1 10 Input power require ments are listed in paragraph 2 15 OUTPUT Model 62568 6 16 voits at 0 20 amps 62638 0 20 volts at 0 10 amps 6264B 0 20 volts at 0 20 amps 6265B 0 40 volts at 0 3 amps 6266B 0 40 volts at 0 5 amps 6267B 0 40 volts at 0 10 amps 62718 0 60 volts at 0 3 amps 62748 0 60 volts at 0 15 amps LOAD EFFECT LOAD REGULATION Constant Voltage Less than 0 01 of output plus 200 for a load change equal to the current rating of the supply Constant Current Less than 0 0296 of output plus for a load change equal to the voltage rating of the supply SOURCE EFFECT LINE REGULATION Constant Voltage Less than 0 01 of output plus 200uV for a change in line voltage between 104 and 127 or 208 and 254 Vac at any output voltage and current within rating Constant Current Less than 0 02 of output plus 5 for a change in line voltage between 104 and 127Vac or 208 and 254Vac at any output voltage and current within rating PARD RIPPLE AND NOISE Constant Voltage Less than 200uV rms 10mV p p 20Hz to 20MHz except for the Model 6274B which has less than 200uV rms or 20mV Constant Current Models 62568 6264B and 6274B Less than 5mA rms 20Hz to 20MHz Models 6263B 6265B 6266B 6267B and 6271B Less than 3mA rms 20Hz t
57. 7 CURRENT FINE contro 62568 64B var ww 10 Series 43 12697 2100 1857 6263B 65B 66B 67B var ww 100 Series 43 12697 2100 1987 71 74 i R40 fxd comp 33k 5 1 2W EB 3335 01121 0686 3335 R109 OVERVOLTAGE ADJUST 62558 var ww 2 5 Series 43 12697 2100 2745 6263B 64B var ww 5k Series 43 12697 2100 1853 6265B 668 67B var ww 10k Series 43 12697 2100 1854 62718 748 ww 20k Series 43 12697 2100 1855 51 6256B 63B 64B 65B switch DPST toggie LINE 8926K317 27191 3101 0946 66B 67B 71B C19 62568 648 62678 62748 CR11 CR34 6256B 64B 678 6274B Q6 7 6256B 64B Rear Panel Electrical See Note 2 fxd elect 22uF 35V fxd elect 15uF 50V fxd elect 10uF 100V diode Si 100V 40A diode Si 100V 40A power NPN Si power NPN Si power NPN Si 1500226 X0035R2 150D156X0050R2 30D106F100DC2 1N1184A 1N1184AR 40250 60744 2N3771 0180 0160 0180 1834 0180 0091 1901 0317 1901 0318 1854 0224 1854 0464 1854 0245 nearest commercial equivalent center collector lead is cut off Note 2 Models 6256B 64B 678 74B only The rear panel components of the remaining models are included under Chassis Electrical 6 11 REF DESIG AND MODELS Q6 7 6267B 6274B R54 62568 648 62678 62748 B1 6274B C13 6256B 64B 6267B 6274B C14 6256B 64B 62638 66B 6265B 62718 748 20 6256B 638 64B 6265B 62668 6267B 6271B 748
58. 720 R49 6K a 12K I 27 4K 1 VOW 39K BW 854 025 025 059 0333 R57 471 1 1 8 471 1 8W 600 8 500 1 1 9W R 4 T75K 1 5 8w TSK i 75X IS vew 150K 195 179W RES JAIK KAW 349K IW 5 49 1 1 80 91K 1 1 8W R66 215 1 21 5 I5 8W 100 1 1 8W 100 Ie 1 8W RET 150 5 IOW 130 3 0 400 5 IOW 800 5 1OW RTS 93K 5 43K 5 VOW 43K 5 2w 1K 1 20 75 5 2 00 99 1720 390K 5 V2W 300K 5 I 2w R79 PAKSA 2W 24K 5 2W 24K 5 2W 51K 5 1 2W R66 SIK S 72W 100 5 2 OOK 5 1 20 5 1 24 R87 3 3K 555 1 2w 33K S 2W 33K U2W 62K 5 I 2W R96 270 35 2W 270 5 2 560 5 2W 270 5 26 470 1 VOW 470 1 1 4W 470 11 49 14 25K 20K SCHEMATIC NOTES L 2 3 12 13 16 ALL RESISTORS ARE IN OHMS 1 2 55 UNLESS OTHERWISE NOTED ALL 08W ANO 1 4W RESISTORS ARE 21 UNLESS OTHERWISE NOTED ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE NOTED REAR TERMINALS ARE SHOWN IN NORMAL STRAPPING FOR USE OF FRONT PANEL CONTROLS CS DENOTES FRONT PANEL MARKING DENOTES VOLTAGE FEEDBACK PATH DENOTES CURRENT FEEDBACK PATH TRANSFORMERS AND RFI CHOKE SHOWN STRAPPED FOR IISVAC OPERATION DC VOLTAGES WERE MEASUREO UNDER THE FOLLOWING CONDITIONS HEWLETT PACKARD MODEL 427A OR EQUIVALENT 8 INPUT VOLTAGES REFERENCED S
59. 8 718 1 6256 6263B 62648 6265B 66B 6267B 6271B 6274B Table 6 4 Replaceable Parts DESCRIPTION pulse transformer diode zener 6 2V diode zener 4 22V diode zener 6 19V diode zener 2 37V dual diff amp IC resistor network A2 RFI Filter Ass y See Note 1 fxd paper 1 250V fxd paper 047uF 250Vac fxd cer 5000pF 1kV thyristor Si Triac thyristor Si Triac jumpers for 115Vac operation inductor fxd met ox 1 5k 596 2W fxd met ox 330 596 2W fxd met ox 180 596 2W fxd met ox 220 596 2W varistor 250Vac Front Panel Electrical fxd cer OIF 3kV fxd O1uF 3kV circuit breaker 20A 250Vac LINE ON indicator light neon OVERVOLTAGE indicator light LINE fuse fuse 8A 250V fuse 5A 250V fuse 10A 250V fuse 4A 250V BIAS fuse 1 10A 250V voltmeter 0 12Vdc voltmeter 0 24 Vdc voltmeter 0 24 Vdc voltmeter 0 50 voltmeter 0 50 voltmeter 0 70 voltmeter 0 70Vdc nearest commercial equivalent rte 6 10 PART NUMBER 1N825 SZ 10939 74 SZ 10939 122 52 10939 2 CA 3026 0238 10265022531 2 5446 5 250 2 42 FP 42 FP 42 FP 42 V250LA40B 41 121 5 41C121A5 CDH AM2 A3 A 20 2 599 237 White MCL B3 1738 314008 314005 314010 312004 313 100 CODE 28480 28480 56289 03508 28480 27167 27167 27167 27167 03508 56289 56289 74193 72765 07137
60. CEDURE 3 2 The following steps describe the use of the front panel controls and indicators illustrated in Figure 3 1 and serve as a brief check that the supply is operational This checkout procedure or the more detailed performance test of paragraph 5 5 should be followed when the instru ment is received and before it is connected to any load equipment Proceed to the more detailed test and trouble shooting procedures in Section V if any difficulties are encountered a Turn CURRENT controls Qo and OVERVOLTAGE ADJUST potentiometer fully clockwise and check that rear panel straps are connected as shown in Figure 3 2 but do not connect load CAUTION Do not energize a Model 62568 62648 62678 62748 supply unless the jumpers are installed that connect together the two terminals and the two terminals b Ptug in line cord 62638 62658 62668 62718 or connect ac power of the appropriate voltage and frequency to the rear panel ac and acc terminals Models 3 1 62568 62648 62678 6274B The suppl y s input rating is identified on its rear panel CAUTION Do not interchange the ac and acc input lines connect the ac input terminal to the hot side and the acc input terminal to the grounded side of the ac line Do not fail to connect the input ground terminal i securely to external earth ground Set LINE switch or circuit breaker 1 ON and observe tha
61. Constant voltage Poor load regulation Constant current Oscillates Constant current or constant vo tage Instability Constant current constant voltage Cannot reach maximum output Check fuses or inspect LINE circuit breaker PROBABLE CAUSE Ground loops in operating setup Refer to paragraph 5 17 b incorrect reference or bias voltages Refer to Table 5 2 Supply crossing over to constant current operation under loaded conditions Check current limit setting or constant current comparator circuit Z1 and associated components Improper measurement technique Refer to paragraph 5 13 Incorrect reference or bias voltages Refer to Table 5 2 Improper measurement technique Refer to paragraph 5 11 Incorrect reference or bias voltages Refer to Table 5 2 Supply current limiting Check constant current comparator circuit Z1 and associated components Incorrect reference or bias voltages Refer to Table 5 2 Supply voltage limiting Check constant voltage comparator circuit 21 and associated components and voltage clamp circuit Q10 Leaky C19 C20 CRY defective Adjustment of R30 Refer to paragraph 5 82 b Faulty C5 C6 C19 C20 R30 R33 Open sensing lead 4S Incorrect reference or bias voltages CR9 defective Refer to Table 5 2 Noisy voltage or current controls R10 R11 or R16 R17 integrated circuit Z1 defective CR1 CR2 CR5 or CR6 leaky R1 R2
62. E controls fully clockwise c Turn on supply and adjust CURRENT controls until digital voltmeter reads 500mV d Adjust R63 until front panel ammeter indicates exactly maximum rated output current 5 70 Constant Voltage Programming ers eee 5 71 Zero Output Voltage Standard Instrument calibrate the zero voltage programming accuracy of a standard instrument proceed as follows a Connect digital voltmeter between the S and 5 terminals observing correct polarity b If unit is to be used in local programming mode turn VOLTAGE controis fully counterclockwise If unit is to be used in remote programming mode connect remote programming setup Figure 3 4 or 3 5 and adjust remote resistance or voltage to zero Rotate CURRENT controls fully clockwise and turn on supply d Observe digital voltmeter reading If reading is more positive than O volts shunt resistor R6 with decade resistance box e Adjust decade resistance unti digital voltmeter reads exactly zero then shunt R6 with fixed metal film 1 1 4 or 1 8 watt resistor of value equal to that of decade box f If reading of step d is more negative than Q volts shunt resistor R8 with decade resistance box g Adjust decade resistance until digital voltmeter reads exactly zero then shunt R8 with fixed metal film 51 1 4 or 1 8 watt resistor of value equal to that of decade box NOTE The internal temperature rise of the powe
63. ED FOR TO OUTPUT CAPECITOR DISCONNECT mx 18 n FRONT PANEL DIMENSIONS 2 448 88 ima HIGH 19 000 422 6 WIDE 0 19014 RACK 0 374 1 t3 Sem 32 23 REAR SIDE Figure 2 1 Outline Diagrams rack mounted in a conventional 19 inch rack panel using standard mounting screws 2 15 INPUT POWER REQUIREMENTS 2 16 The standard instrument as shipped from the factory is wired for a nominal input of 115Vac 57 63Hz Instruments with special options also available from the factory include some equipped for 208 volt or 230 volt operation Option 027 or 028 and for 50Hz operation Option 005 The required input voltage and frequency is marked on the rear panel of the supply The standard instrument can also be converted by the user to 208 volt or 230 volt and to 50Hz operation by following the instructions given in the following paragraphs The standard instrument requires the input current and power listed below when operated at full load from a 115 volt source When the supply is operated from a 208 volt or 230 volt source the input current is approximately half the amount listed Model Input Current Input Power 6256B 5A 375W 6263B 4A 350W 6264B 8A 600W 62658 TROW 6256 4 325W 6267B 8A 550W 6271B 4A 300W 6274 1 1200W 2 17 INPUT LINE VOLTAGE OR FREQUENCY CONVERSION 2 18 When it is wired for 115 volt opera
64. ESTED METHOD OF BUILDING LOAD SWITCH HOWEVER OTHER METHODS COULD BE USED SUCH 5 i A TRANSISTOR SWITCHING NETWORK MAXIMUM LOAD RATINGS OF LOAD SWITCH ARE 5 AMPS 500 V 250W 1 NOT 2500W 2 USE MERCURY RELAY CLARE TYPE HPG 1002 OR W E TYPE 276 3 USE WIREWOUND RESISTOR REPETITIVE LOAD SWITCH NOTE 1 115 MED ES 2 22 50 42 100 40 100W 13 30 120W 200W 80 200w 209 180W 122 Figure 5 4 Load Transient Recovery Time Test Setup Eout UNLOADING TRANSIENT NOMINAL OUTPUT VOLTAGE LOADING TRANSIENT ja 8 35 NOMINAL OUTPUT TIME A VOLTAGE SOySEC SO SEC M NOMINAL OUTPUT TIME VOLTAGE UNLOADING LOADING TRANSIENT TRANSIENT Figure 5 5 Load Transient Recovery Time Waveforms 5 31 Temperature Coefficient Definition The change in output voltage per degree Celsius change in the ambient temperature measured while ac line voltage output voltage setting and load resistance are al held constant 5 32 The temperature coefficient of a power supply is measured by placing the power supply in an oven and vary HP power supplies are rated for operation from 0 C to 55 C The power supply temperature must be allowed to stabilize for a sufficient time at each measurement tempera ture 5 33 The temperature coefficient given in the spe
65. GNORES DIFFERENCE IN GROUND POTENTIAL OF POWER SUPPLY amp SCOPE AND SHIELDED TWO WIRE FURTHER REDUCES STRAY PICK UP ON SCOPE LEADS Figure 5 2 Ripple Test Setup 5 19 Although the method shown in Figure 5 2A is not recommended for ripple measurements it may prove satisfactory in some instances provided certain precautions are taken One method of minimizing the effects of ground current flow 16 is to ensure that both the supply and the test instrument are plugged into the same ac power bus 5 20 To minimize pickup a twisted pair or preferably a shielded two wire cable should be used to connect the sensing terminals of the power supply to the vertical input terminals of the scope When using a twisted pair take care that the same wire is connected both to the grounded terminal of the power supply and the grounded input terminal of the oscilloscope When using shielded two wire cable it is essential for the shield to be connected to ground at only one end to prevent any ground current flowing through this shield from inducing a signal in the shielded leads 5 21 To verify that the oscilloscope is not displaying ripple that is induced in the leads or picked up from the grounds short the scope lead to the scope lead at the power supply terminals The ripple value obtained when the leads are shorted should be subtracted from the indicated ripple measurement 5 22 If the foregoing measures are used the single ended sco
66. OD outside diameter pico 10712 printed circuit potentiometer pp peak to peak ppm parts per million peak reverse voltage rect rectifier rms root mean square Si silicon SPDT single pole double throw SPST single pole single throw SS small signal T slow blow tan Ti titanium V volt var variable ww wirewound Ww Watt ODE 00629 00656 00853 01121 01255 01281 01295 01686 01930 02107 02114 02606 02660 02735 03797 03877 03888 04009 04072 04213 04404 04713 05277 05347 05820 06001 06004 06486 06540 06555 06666 06751 06776 06812 Use Code 28480 assigned to Hewlett Packard Co Palo Alto California Table 6 3 Code List of Manufacturers ADDRESS Jamaica N Y New Bedford Mass MANUFACTURER EBY Sales Co Inc Aerovox Corp Sangamo Electric Co S Carolina Div Pickens S C Allen Bradley Co Milwaukee Wis Litton Ind Beverly Hills Caiif TRW Semiconductors Inc Lawndale Calif Dallas Texas Manchester N H Rockford 111 Dover Ohio Saugerties N Y Texas Instruments Inc RCL Electronics Inc Amerock Corp Sparta Mfg Co Ferroxcube Corp Fenwal Laboratories Morton Grove Ill Amphenol Corp Broadview llt Radio Corp of America Solid State and Receiving Tube Div S
67. OPERATING REGION SHORT CIRCUIT LOAD Eg FRONT PANEL VOLTAGE CONTROL SETTING 16 FRONT PANEL CURRENT CONTROL SETTING Es CRITICAL OR CROSSOVER VALUE OF LOAD RESISTOR Figure 4 2 Operating Locus of a CV CC Power Supply 4 2 4 14 The reference supply provides stable reference voltages used by the constant voltage and current compara tors Less critical operating voltages are obtained from an unregulated bias supply 4 5 DETAILED CIRCUIT ANALYSIS See Figure 7 4 or 7 7 4 16 Preregulator Control Circuit 4 17 The preregulator minimizes the power dissipated by the series regulating transistors during input line voltage or dc output voltage variations Preregulation is accom plished by a phase control circuit using triac A2CR1 as the switching element 4 18 The triac is a bi directional device that is it can nameet nmiirrant in aithar diractinn hanna tha device fiva S ee 1 ERR ww Q whenever it receives gating pulse regardiess of the polarity of the ac voltage applied to it The triac is fired once during each half cycle of the ac input see Figure 4 3 Notice that when the triac is fired early in the half cycle the ac level applied to the power transformer is relatively high When the triac is fired later in the half cycle the ac level is relatively low 4 19 Normally the ac input must be a
68. OV PROTECTION VOLTAGES REFERENCED TO 5 UNLESS OTHERWISE NOTED D VOLTAGES ARE TYPICAL 10 UNLESS OTHERWISE NOTED ALL READINGS TAKEN IN CONSTANT VOLTAGE OPERATION AT MAXIMUM RATED OUTPUT WITH NO LOAD CONNECTED ANO CURRENT CONTROLS li TURNED FULLY CLOCK WEE 10 ALL COMPONENTS LOCATED ON MAIN PRINTED CIRCUIT BOARD UNLESS OTHERWISE INDICATED OUTPUT A 1 TI REGULATOR GENERATOR DENOTES CHASSIS MOUNTED COMPONENTS LER 2 PIN LOCATIONS FOR INTEGRATED CIRCUITS ARE AS FOLLOWS FROM 12V TOUT UNREG VIE WS 4 Gut care PIN LOCATIONS FOR SEMICONDUCTORS ARE 5 FOLLOWS 1 Wa s ECA lt TO 5 PL 5 OT ga S 00 TO 3 70 66 TOP VIEWS m 50 3 TRIAC R TOP VIEWS TOP VIEW ACRI 87 14 JUMPERS 7 28 REMOVED WHEN SUPPLY 16 EQUIPPED WITH OPTION 020 022 OR 040 JUMPERS 5 8 6 REMOVED WHEN SUPPLY IS EQUIPPED WITH OPTION 021 022 OR O40 15 FOR 115 INPUT CONNECT JUMPERS Jl 42 3 44 AND OISCONNECT J3 FOR 208 OR 25 INPUT CONNECT AND DISCONNECT Jl 44 16 SEE FIGURE 4 4 FOR PREREGULATOR CONTROL CIRCUIT WAVEFORMS PREREGULATOR C NOTE I gt gt NT DR R20 1749 CRS OPTION 021 SEO ONLY 22 3 Ris 200K WBW 6 2V i RIS 26 SELECTED SW AT e A6 CURENT E 45
69. PROTECTION 00 NOT czo REMOVE z 5 226 emer Two JUMPERS Figure 7 4 Models 6256B 6264B 6267 and 6274B Schematic Diagram SCHEMATIC TABLE EET sus 58 REFERENCE SaF SOV SaF 50V 50V SaF 65V 400004 SOV 220004 50 40000 Sov 2200045 SOV 2e F 35V ISuF 50V SOV IQF 100V 86007 25V 4500 F 3 V 5000F 50V 16 85V FI SA 4 5 RI IK 5 1 5 IK 5 2K 5 5W R2 82 5 2 4 160 5 1 2 1650 5 2 240 5 172W R9 600 5 SW 600 5 Sw 600 5 5 1K 5 5w RIO 5k 10K 20K RII 5 109 Ri2 680 5 SW 680 5 5 680 5 SW IK 5 5 SOME CIRCUITS IN THIS POWER SUPPLY RIS T5OK 5 2W S60K 5 VOW 9 2 750K 5 172W ARE CONNECTED DIRECTLY TO THE INPUT AC POWER LINE THE CASE AND HEAT R49 12K 1 1 BW 27 4K 1 1 8W 274K 1 178W 39K SINK OF THE A2 RAI ASSEMBLY ARE ALSO AT AC LINE POTENTIAL EXERCISE EX me j gone 016 Srog TREME CAUTION WHEN WORKING ON ENER R57 1 8 4 600 1 Bw 600 1 ew 600 1 vew 5260 CIRCUITS 390 5 3w 390 5 3w 390 5 5W 135 5 3 65 100 1 1 BW 196 1 1 44 I9 amp I I 8W 196 1 1 8 867 150 4 109 600 5 10W 400 5 10W 00 5
70. R74 43 5 43 5 5 R76 16OK 5 1 2W ZOOK S 1 2W 200 4 2 300K 5 1 2W R86 100 5 200K 5 2W 200K 5 172W 00 5 1 20 R96 560 5 2W 15 5 2 1 5 2 270 5 2W 98 270 5 1 2W 270 5 2 270 5 2 1 5K 5 12W R99 300 5 2 100 5 2w 100 5 100 4 RIOS 470 1 aw 470 7 4 4 L33K Ya RIOA 133K 1m YEW 133K 1 Uaw 2K 1 1740 5k 10K 10K 20K 5 ON 2 ASSEMBLY 22 e RVI La CES ca ot 200 Ps 15K SCHEMATIC NOTES ew ALL RESISTORS ARE IN OHMS I 2W 525 UNLESS OTHERWISE NOTED D T 1 2 ALL 0W AND l 4W RESISTORS ARE 1 UNLESS OTHERWISE NOTED 250v 2 3K 3 ALL CAPACITORS ARE IN MICROFARADS UNLESS OTHERWISE NOTED gure 4 PEAR TERMINALS ARE SHOWN iN NORMAL STRAPPING SOR USE OF FRONT i 5 1 PANEL CONTROLS 4 a i 5 CIZ DENOTES FRONT PANEL MARKING J2 gt 500 T SEE TABLE iB 1 R3 H 6 OENOTES VOLTAGE FEEDBACK PATH 3 2 NOTE i DENOTES CURRENT FEEDBACK PATH 250v 2 8 TRANSFORMERS AND CHOKE SHOWN STRAPPED FOR 115 OPERATION m zr 9 OC VOLTAGES WERE MEASURED UNDER THE FOLLOWING CONDITIONS ge A HEWLETT PACKARD MODEL 427A OR EQUIVALENT FROM FROM B 5 VAC INPUT
71. TAGE control fully CCW and remove the short circuit Adjust the VOLTAGE control for an output voltage 0 7 volts greater than the desired full charge voltage The added 0 7 volts compensates for the drop actoss CRp The supply may then be connected to the battery terminals positive to positive and negative to negative as shown in Figure 3 14 omit Ry 3 82 Taper Charge When charging lead acid cells many manufacturers recommend that the charging current be reduced as the charge nears completion This can be accomplished by inserting a small resistance series with one of the load leads from the supply to the battery See Figure 3 14 This resistor alters the normally rectangular charging piot in such a manner as to provide taper charge for the last portion of the charge The proper value for this resistor is the difference between the full charge voltage and the voltage at which the tapering is to start divided by the initial charging current Set the initial charging rate and full charge voltage as instructed in paragraph 3 81 3 83 Battery Discharging 3 84 These power supplies are also useful when batteries must be discharged at a constant current in order to test them Connecting a supply as shown in Figure 3 15 and following the instructions below makes an unattended constant current discharge possible by automatically shutting off the output of the supply when the battery voltage reaches zero 3 85 The supp
72. ade to permit the overvoltage crowbar in any one of the interconnected supplies to fire the SCRs in all of them if an overvoltage condition occurs The circuit board pads to be interconnected are marked EXT TRIG and their locations are indicated on the component location diagrams in Section VIl Be sure to connect them with correct polarity terminal 5 to 5 and 6 to 6 Set the overvoltage potentiometer in each supply so that it trips at a point slightly above the voltage that supply wil contribute 3 57 Auto Series With Remote Sensing To combine auto series operation with remote sensing connect the supplies as described above but remove the S jumper from the master suppiy and the S jumper from the last slave supply and connect the S and S terminals directly to the and ends of the load Observe the precautions outlined under paragraph 3 25 3 58 Auto Series With Remote Programming When two or three supplies are connected in auto series their combined output voltage current or both can also be remotely programmed Refer to the appropriate sections of paragraph 3 32 for the additional rear panel connections 3 10 required and make these connections to the master supply only Observe all precautions outlined in the paragraphs on remote programming The simultaneous use of remote sensing and remote programming is also possible during auto series operation 3 59 Auto Tracking Operation 3 60 Figures 3 12 a
73. age limit to be exceeded the supply automatically crosses over to constant voltage opera tion at this preset voltage limit and the output current drops RR d ree proportionately In setting the voltage limit make an adequate allowance for high peak voltages that could cause unwanted crossover Refer to paragraph 3 69 3 12 Overvoltage Trip Point Adjustment 3 13 The crowbar trip voltage is adjusted by using the screwdriver control on the front panel The approximate trip voltage ranges are listed in Table 1 1 When the crowbar trips an SCR shorts the output and the amber OVER VOLTAGE indicator on the front panel lights Rotating the control clockwise sets the trip voltage higher it is set to maximum at the factory Paragraph 5 92 contains instruc tions for completely disabling the crowbar if this is desired 3 14 When adjusting the crowbar trip point the possibility of false tripping must be considered f the trip voltage is set too close to the supply s operating voltage transient in the output would falsely trip the crowbar For this reason it is recommended that the crowbar be set higher than the output voltage by 7 of the output voltage plus one volt 3 15 Connecting The Load 3 16 To satisfy the requirements of safety the wires to the load should be at least heavy enough not to overheat while carrying the power supply current that would flow if the load were shorted Generally heavier wire than this is r
74. ale Electronics Inc Columbus Neb Elco Corp Willow Grove Pa Honeywell Inc Freeport lil Whitso Inc Schiller Pk Hl Sylvania Electric Prod Woburn Mass Essex Wire Corp Mansfield Ohio Raytheon Co Quincy Mass Wagner Electric Corp Livingston N J Southco Ine Lester Pa Leecraft Mfg Co Inc LUG N Y Methode Mfg Co Rolling Meadows 111 Bendix Corp Franklin nd Weckesser Co Inc Chicago til Amphenol Corp Janesville Wis Industrial Retaining Ring Co Irvington N J IMC Magnetics Corp Westbury N Y Sealectro Corp Mamaroneck N Y ETC inc Cleveland Ohio International Electronic Research Corp Burbank Calif Renbrandt Inc Boston Mass 4 Table 6 4 Replaceable Parts REF DESIG MODELS DESCRIPTION 1 Main PC Board See Note 1 Ci 62568 638 648 658 fxd elect 50V 66B 67B 6271B 74B fxd elect 65V C3 fxd polyester 0 1uF 200V C5 6256B 63B 64B 65B fxd polyester 1000pF 200V 668 678 718 62748 fxd polyester 2200pF 200V C6 7 C9 fxd polyester O1uF 200V fxd elect 4 7uF 35V man fu el ee Cid fxd elect 100 7 SOY C11 fxd cer OSuF 500V C12 fxd elect 325uF 35V C15 fxd elect 1uF 35V 16 17 fxd elect 50V C18 fxd polyester 0 224F 80V C19 6263B fxd elect 22uF 35V 62658 668 fxd elect 15uF 50V 62718 fxd elect 10 100V C2
75. an its rated maximum outputs Operation can extend into the shaded areas on the meter faces without damage to the supply but performance cannot be guaranteed to meet all specifications 3 22 OPTIONAL OPERATING MODES 3 23 The optional operating modes discussed in the following paragraphs include a Remote voitage sensing b Remote programming Auto Parallei operation d Auto Series operation e Auto Tracking operation Special operating instructions for instruments equipped with Option 040 to permit their interfacing with a Model 69408 Multiprogrammer or a 6941B Multiprogrammer Extender are not included but can be found in the manual covering the programmable resistance cards that neces sary to complete the interface Special calibration instruc tions for power supplies equipped with Option 040 are included in Section V of this manual 3 24 By changing its rear panel strapping pattern according to the instructions which follow any of the MODELS 62568 62648 62678 62748 2 A4 5 A7 S AS AIO 5 cla 91 1912191 12191919219 MODELS 62638 62658 62668 62718 2 4 AS AT 5 GNDAB 5 eleleleiaieleleleialelaioial Figure 3 3 Remote Sensing supplies covered by this manual can be operated in any of the modes listed above CAUTION Disconnect input ac power before changing any rear panel co
76. at the power supply will not be damaged by the rapid repetitive program ming possible with the multiprogrammer This option includes Option 022 040 INSTRUMENT MANUAL IDENTIFICATION 1 12 1 13 Hewlett Packard power supplies are identified by a two part serial number The first part is the serial number Eel ee es 0 m prefix a number ietter combination that denotes the date of a significant design change and the country of manu facture The first two digits indicate the year 10 1970 11 1971 etc the second two digits indicate the week and the letter designates the U S A as the country of manufacture The second part is the power supply serial number A different sequential number is assigned to each power supply starting with 00101 1 14 If the serial number on your instrument does not agree with those on the title page of the manual Change Sheets supplied with the manual define the differences between your instrument and the instrument described by this manual 1 15 ORDERING ADDITIONAL MANUALS 1 16 One manual is shipped with each power supply Additional manuals may be purchased from your local Hewlett Packard field office see list at rear of this manual for addresses Specify the model number serial number prefix and HP part number shown on the title page Table 1 1 Specifications Models 6256B 6263B 6264B 6265B 6266B 6267B 6271B and 6274B INPUT 115Vac 10 single phase 5
77. attern shown on the schematic is used This capacitor can be removed by unstrapping terminal AB to avoid output current surges or to increase the programming speed of the supply If C20 is removed capacitor C19 insures Icop stability 4 37 Constant Current Comparator 4 38 The constant current comparator is similar in appearance and operation to the constant voltage compara tor it consists of programming resistors 16 and 17 differential amplifier 21 and associated components 4 39 The constant current comparator circuit compares the voltage drop across the CURRENT controls with the voltage drop across current sampling resistor R54 Ifa difference exists the differential amplifier produces an error signal proportional to this difference The remaining components in the feedback loop amplifiers and the series regulator maintain the drop across the current sampling resistor and hence the output current at a constant value 4 40 One input of the differential amplifier pin 7 is connected to the output bus through impedance equalizing resistor R26 115 other input pin 4 is connected to a summing point terminal A6 at the junction of program ming resistors R16 and R17 and current pullout resistors R18 and R19 Instantaneous changes in the output current due to load changes or changes in the voltage at the summing 4 5 point due to changes in the CURRENT control setting produce a difference voltage between
78. be observed when connecting units in this fashion 4 55 Turn On Control Circuit 4 56 The turn on control circuit is long time constant network which protects the triac and the series regulator from possible damage during turn on When the supply is first turned on C22 applies a positive voltage to the anodes of CR47 and 50 Diode CR50 couples this voltage to the cathode of CR44 in the preregulator control circuit to ensure that it is initially reverse biased After C22 becomes sufficiently charged CR50 becomes reverse biased and the preregulator contro circuit is permitted to fire the triac 4 57 Diode CR47 performs a similar function for the series regulator This diode initially couples a positive voltage to Q5 which inverts it and applies it to the series regulator This negative voltage keeps the regulator cut off until C22 charges up Diode CR45 provides a discharge path for C22 when the supply is turned off 4 58 Reference Regulator 4 59 The reference circuit is a feedback power supply similar to the main supply It provides stable reference voltages used throughout the unit All the regulated reference voltages are derived from dc obtained from full wave rectifier CR10 and CR12 and filter capacitor C10 Zener diodes VR1 and VR2 establish well regulated poten tials of 6 2V and 6 2V with respect to common point S while the regulator circuit establishes a well regulated potential of 12 4 volts Resistor R48 esta
79. bleshoot this instrument ensure that the fault is with the instrument and not with an associated circuit The performance test paragraphs 5 5 through 5 48 enables this to be determined without removing the instrument from the cabinet 5 51 good understanding of the principles of opera tion is a heipful aid in troubleshooting and it is recom mended that the reader review Section IV of the manual before attempting to troubleshoot the unit in detail Once the principles of operation are understood refer to the troubleshooting procedures in paragraph 5 54 to locate the symptom and probable cause 5 52 The schematic diagram contains normal voltage readings adjacent to some test points Test points are identified by circled numbers The measurement conditions are listed in the Schematic Notes Consult the component location diagrams in Section VII to determine the locations of components and test points 5 53 If a component is found to be defective replace it and re conduct the performance test When a component is replaced refer to the repair and replacement paragraph 5 60 and adjustment and calibration paragraph 5 62 sections of this manual 5 54 OVERALL TROUBLESHOOTING PROCEDURES 5 55 To locate the cause of trouble follow steps 1 2 and 3 in sequence 1 Check for obvious troubles such as a defective power cord an input power failure or a defective meter Next remove the top and bottom covers an
80. blishes an opti mum bias current through the zener diodes 4 60 The regulating circuit consists of series regulating transistor Q9 driver Q16 and differential amplifier 014 015 The voltage across zener diodes VR1 and VR2 is compared to the voltage across resistor Z2J and any difference is amplified by Q14 and Q15 The error voltage thus appearing at the collector of Q14 is amplified by driver stage Q16 and applied to series regulator Q9 in the correct phase and amplitude to maintain the 12 4 voit output at a constant level 4 61 Diode CR7 connected from voltage divider R34 and R39 to the base of Q16 serves as a turn on circuit for series regulator transistor Q9 When the supply is first turned on CR7 biases driver Q16 on thus turning on the series regulator When the reference supply reaches normal output the base voltage of 016 is sufficient to reverse bias CR7 thus effectively removing it from the circuit Capacitor C9 connected across the output of the reference supply removes spikes and stabilizes the reference regulator loop 4 62 A separate winding on transformer T2 diodes CR13 and CR 4 and filter capacitor C12 provide an un regulated 12 output Additional reference voltages of 2 4 volts and 4 8 volts are provided by zener diodes VR6 VR7 Resistor R60 biases the zeners Diode CR15 prevents reverse current flow from damaging the main supply series regulator transistor s Diode CR20 shown on
81. bove a certain minimum potential before a triac will conduct However A2C1 and A2R1 provide a holding current that allows the triac to conduct at any time during the ac input cycle choke A2L1A A2L18 slows down the turn on of the triac in order to minimize spikes at the output of the supply AC INPUT TO SUPPLY LATER NT FIRING POINT Umm LOW TRANSFORMER Figure 4 3 Triac Phase Contro of AC Input Amplitude The components of the A2 Assembly are all mounted inside a shielded box to minimize radiated and reflected RFI Further RFI suppression is provided by line bypass capacitors 4 20 The preregulator control circuit samples the input line voltage the dc input to the series regulator and the volt age across the series transistor It generates firing pulses that fire the triac and adjusts the phase of these pulses so that the dc voltage across the series regulator remains constant 4 21 The inputs to the control circuit are algebraically summed across capacitor C15 All inputs affect the time required to charge C15 The input line voltage is rectified by CR27 CR28 CR31 and CR33 attenuated by voltage divider R68 and R69 and applied to the sumrning point at the collector of Q22 TP73 via capacitor C15 Capacitor C18 is used for smoothing purposes 4 22 Transistor Q22 connected in a common base con figuration provides a charging current to the summing capacitor which varies with the
82. but omit step e and change step f as follows connect the T2 input lead to the 230 tap instead of the 208 tap See Figures 2 2C and 2 3C 2 25 Converting A Standard Instrument To 50Hz Operation 2 26 To convert 60H2 instrument to 50Hz operation proceed as follows a Replace R74 R76 R78 and R79 if new values are listed below HP Part Numbers for these resistors may be found on page 6 16 of the parts list Model R74 R76 me 6256B 150 22 750 6263B 200k22 27082 4 7kQ 6264B 200 9 2709 4 7kQ 6265B 2709 4 7kQ 6266B 8 2 9 150kQ 2702 4 7kQ 6267B 750k 2 27022 4 7kQ 6271B 360k4 2702 4 7kQ 6274B 430 0 2709 b After replacing the necessary resistors perform the preregulator tracking adjustment procedure given in para graph 5 86 Check the ripple balance adjustment by the procedure given in paragraph 5 84 227 POWER CABLE 2 28 To protect operating personnel the National A TRANSFORMER PRIMARY CONNECTIONS FOR 115 VOLT OPERATION T2 TRANSFORMER PRIMARY CONNECTIONS FOR 208 VOLT OPERATION amp T2 TRANSFORMER PRIMARY CONNECTIONS FOR 230 VOLT OPERATION TI amp Figure 2 2 Transformer T1 and T2 Primary Connections for 208V and 230V Operation except T2 in Model 6274B 2 3 Electrical Manufacturers Association NEMA recommends that the instrument panel and cabinet be grounded Mo
83. can be remotely programmed but their currents cannot Refer to the appropriate sections of paragraph 3 32 for the additional rear panel connections required and make these connections to the master supply only Observe all precautions outlined in the paragraphs on remote programming The simultaneous use of remote sensing and remote programming is also possible during auto tracking operation 3 68 SPECIAL OPERATING CONSIDERATIONS 3 69 Pulse Loading 3 70 The power supply automatically crosses over from constant voltage to constant current operation or the reverse in response to an increase beyond the preset voltage or current limit Although the preset limit may be set higher than the average output current or voltage high peak currents or voltages may exceed the preset limit and Cause crossover to occur If this current or voltage limiting is not desired set the current or voltage controls somewhat above the peak rather than the average requirement 3 71 Output Capacitance 3 72 An internal capacitor C20 connected across the output terminais of the supply heips to suppiy high current pulses of short duration during constant voltage operation In applications where the availability of high peak output currents should be reduced this capacitor can be removed from the circuit by removing the strap connected between rear panel terminals A8 and 4 NOTE The removal of C20 from the circuit may permit the supply to oscillate If the
84. cifi cations is the maximum temperature dependent output voltage change which will result over any one degree interval The digital voltmeter used to measure the supply s output voltage change should be placed outside the oven and should have a long term stability adequate to insure that its drift will not affect the overall measurement accuracy 5 34 To check the temperature coefficient proceed as follows a Connect load resistance and digital voltmeter as illustrated in Figure 5 1 b Turn CURRENT controls fully clockwise c Turn on supply and adjust front panel VOLTAGE controls until front panel voltmeter indicates maximum rated output voltage d Place power supply in temperature controlled oven digital voltmeter remains outside oven Set temperature to 30 and allow 30 minutes warm up Record digital voltmeter reading f Haise temperature to 40 C and allow 30 minutes warm up g Observe digital voltmeter reading Difference in voltage reading between steps e g should be iess than 62568 12mV 62638 6264B 22mV 62658 62668 62678 42mV 62718 62748 62mV 5 35 Drift Stability Definition The change in output voltage for the first eight hours following a 30 minute warm up period During the interval of measurement input line voltage load resis tance and ambient temperature are all held constant 5 36 This measurement is made by monitoring the output of the power supply on a digital v
85. components most likely to be at fault 5 59 After troubleshooting the unit it may be necessary to perform one or more of the calibration procedures given in this section WARNING Some Circuits in this power supply are connected directly to the input ac power line red painted case and heatsink of the A2 RFI Assembly are also at ac line potential Exercise extreme caution when working on energized circuits Table 5 2 Reference and Bias Voltages Refer to schematic and component location diagrams in Section for test point locations TP31 12 4 5 E TP24 6 2 2 12 15 44 NORMAL NORMAL STEP COMMON POSITIVE VDC RIPPLE P P PROBABLE CAUSE 4 8 10 CR13 CR14 C12 VR6 VR7 2 0mV 09 14 15 16 VR1 2 CR7 2 0mV VR1 VR2 R48 CR13 CR14 C12 Table 5 3 Overall Troubleshooting SYMPTOM PROBABLE CAUSE A Low or no output voltage OVERVOLTAGE lamp may be on or off High output voltage a Front panel meter defective b Crowbar not reset or defective Refer to Table 5 4 C Series regulator or preregulator feedback loop defective Refer to Table 5 4 a Front panel meter defective b Series regulator or preregulator loop defective If crowbar does not trip it too is faulty Refer to Table 5 4 5 9 Table 5 3 Overall Troubleshooting Continued SYMPTOM High ripple Poor line regulation Poor load regulation
86. ct 5 6 Leave external source connected 0 10V 1A supply is sufficient 3 Set external supply to ten volts 4 Vary front panel voltage controls Table 5 5 Series Regulator Troubleshooting High Output Voltage STEP ACTION RESPONSE PROBABLE CAUSE Make these tests with external source connected as described in step 3 of Table 5 4 Q6 Q7 CR11 or O3 shorted Output voitage remains high b Output voltage decreases Check turn off of driver and series regulator transistors 06 and Q7 by momentarily shorting rear panel terminal A4 to base of TP45 Proceed to step 2 Output voltage remains O4 open high b Output voltage decreases Check conduction of O4 by momentarily shorting Q12 emitter to collector TP74 to TP45 Proceed to step 3 Check conduction of Q12 by Q12 open momentarily connecting base to collector TP45 Output voltage remains high b Output voltage decreases Proceed to step 4 Q5 shorted Output voltage remains high Output voltage decreases Check turn off of Q5 by moment arily connecting base 84 to emitter TP85 Proceed to step 5 5 11 Table 5 5 Series Regukstor Troubleshooting High Output Voltage Continued NESrUNSE Check turn off of 21 by moment a Output voltage remains open Z1 def
87. current as indicated on the front panel meter MODELS 62568 62648 62678 62748 2 4 AS S 5 MODELS 62638 62658 52556 62718 2 A4 5 AT 5 GND AS 5 Eg INITIAL BATTERY VOLTAGE 1 DISCHARGE CURRENT RATED VOLTAGE OF SUPPLY Eg Ry MINIMUM s xt 10 Figure 3 15 Battery Discharging SECTION IV PRINCIPLES OF OPERATION REFERENCE SUPPLY BIAS SUPPLY POWER TRANS FORMER FILTER PREREG T ULATOR RECTIFIER REG PREREG ULATOR CONTROL CIRCUIT NOTE m DENOTES CONSTANT VOLTAGE FEEDBACK PATH DENOTES CONSTANT CURRENT FEEDBACK PATH SHORT CIRCU T CURRENT 9 PROTECTION CONTROLS M DRIVER ERROR AMPL COMPARATOR di lt lt OLTA c GATE VOLTAGE PROTECTION CONSTANT CURRENT COMPARATOR R54 CURRENT 5 SAMPLING RESISTOR IXER CONSTANT 5 VOLTAGE CROWBAR CIRCUIT Figure 4 1 Overall Block Diagram 4 1 OVERALL BLOCK DIAGRAM DISCUSSION 4 2 The major circuits of the power supply are shown on the overall block diagram of Figure 4 1 The ac input to the power transformer is preregulated by a triac which forms a feedback ioop in conjunction with the preregulator control circuit This feedback loop maintains a low and constant voltage drop across the series regulator in order to mini
88. d be observed when making a remote sensing installation NOTE The 5 jumper is the one that links the 5 terminal to the 4OUT or A10 terminal when the supply s terminals are strapped for normal operation as shown in Figure 3 2 5 jumper is the one that links the S terminal to the OUT or A9 terminal 3 28 The load leads should be of the heaviest practicable wire gauge at least heavy enough to limit the voltage drop in each lead to one volt This limitation is dictated by the adverse effect that a greater load lead voltage drop has on bias voltages within the suppiy when remote sensing is used Twisting the load leads may help to minimize noise pick up 3 4 While there are practical limitations on the distance that separates a power suppiy from its load when using remote sensing it isn t possible to define these limits precisely due to a variety of factors that are unique to each particular installation 3 29 Since the sensing leads carry only a few milliamps the wires used for sensing can be much lighter than the load leads 22 AWG is generally adequate but they should be a shielded twisted pair to minimize the pickup of external noise Any noise picked up on the sensing leads will appear at the supply s output The shield should be grounded at one end only and should not be used as one of the sensing conductors The sensing leads should be connected as close to the load as possible 3 30 T
89. d inspect for open connections charred components or any other visible defects If the trouble source cannot be detected by visual inspection proceed to step 2 2 almost all cases the trouble can be caused incorrect de bias or reference voltages thus it is good practice to check the voltages in Table 5 2 before proceeding with step 3 3 Disconnect the load and examine Table 5 3 for your symptom and its probable cause 5 56 Table 5 3 contains symptoms and probable causes of many possible troubles If either high or low output voltage is a symptom Table 5 4 contains the steps necessary to isolate the trouble to one of the feedback loops and instructions directing the tester to the proper table for further isolation Because of the interactions between loops it is necessary to refer to Table 5 4 before proceeding to Tables 5 5 5 6 or 5 7 5 57 Tables 5 5 5 6 and 5 7 contain troubleshooting procedures for the series regulator and preregulator feedback loops once the fault has been isolated to one of them Tables 5 5 and 5 6 contain instructions for driving each stage into conduction or cut off By following the steps in these tables the fault can be isolated to a circuit or a component 5 58 Table 5 7 contains troubleshooting procedures for the preregulator feedback loop Troubleshooting is accomplished by comparing waveform illustrations with the waveforms found at various test points and then checking the
90. del 6263B 6265B 6266B and 6271B power supplies are equipped with a three conductor power cable When the cable is plugged into an appropriate receptacle the instrument is grounded through the offset pin on its three prong connector In no event shal this instrument be operated without an adequate cabinet ground connection To preserve the protection feature when operating the instrument from a two contact outlet use a three prong to two prong adapter if permitted by local regulations and connect the green lead on the adapter to ground 2 29 Model 62638 62658 6266B and 6271B supplies are equipped at the factory with a power cord plug appro priate for the user s location Figure 2 4 illustrates the standard configurations of power cord niugs used by HP Above each drawing is the HP option number for that configuration of power connector pins Below each drawing BIAS TRANSFORMER T2 CONNECTIONS FOR 115 VOLT OPERATION B BIAS TRANSFORMER T2 CONNECTIONS FOR 208 VOLT OPERATION C BIAS TRANSFORMER 72 CONNECTIONS FOR 230 VOLT OPERATION Figure 2 3 Bias Transformer T2 Primary Connections for 208V and 230V Operation Model 6274B only is the HP part number for a replacement power cord equipped with a plug of that configuration Notify the nearest HP Sales and Service Office if the appropriate power cord is not included with the instrument 2 30 No power cable is suppliedwith Model 62568 626
91. e and Z is the specified load current change of 5 amps or the full load current rating of the supply whichever is less Load transient recovery time may be measured at any input line voltage combined with any output voltage and load current within rating 5 28 Measurement Techniques Care must be taken in switching the load resistance on and off hand operated switch in series with the load is not adequate since the resulting one shot displays are difficult to observe on most oscilioscopes and the arc energy occurring during switching completely masks the display with a noise burst Transistor load switching devices are expensive if reasonably rapid load current changes are to be achieved 5 29 We suggest that a mercury wetted relay connected in the load switching circuit shown in Figure 5 4 be used for loading and unloading the supply When this load switch is connected to a 60Hz ac input the mercury wetted relay opens and closes 60 times per second The 25k con trol adjusts the duty cycle of the load current switching to reduce jitter in the oscilloscope display This relay may also be used with a 50Hz ac input The load resistance shown in Figure 5 4 is the minimum resistance that can be used without damaging the mercury wetted relay contacts 5 30 Measurement Procedure To check the load transient recovery time proceed as follows a Connect test setup shown in Figure 5 4 b Turn CURRENT controls fully clockwise c Tu
92. e made at any input ac line voltage combined with any dc output voltage and load current within the supply s rating 5 16 The amount of ripple and noise present on the power supply output is measured either in terms of its rms or preferably peak to peak value The peak to peak measurement is particularly important for applica tions where noise spikes could be detrimental to sensitive loads such as logic circuitry The rms measurement is not an ideal representation of the noise since fairly high output noise spikes of short duration can be present in the ripple without appreciably increasing the rms value 5 17 Ripple Measurement Techniques Figure 5 2A shows an incorrect method of measuring peak to peak ripple Note that a continuous ground loop exists from the third wire of the input power cord of the supply to the third wire of the input power cord of the oscilloscope via the grounded power supply case the internal jumper connecting the power supply negative output and sensing terminals the wire between the negative sensing terminal of the power supply and the vertical input of the scope and the grounded scope case Any ground current circulating in this loop as a result of the difference in potential between the two ground points causes drop which is in series with the scope input This IR drop normally having a 60Hz line frequency fundamental plus any pickup on the unshielded leads interconnecting the pow
93. ective arily connecting a 10k22 resistor high between 10 89 6 2V b Output voltage decreases b R5 R6 R10 or R11 open strap supply 25 between A1 and A2 open Table 5 6 Series Regulator Troubleshooting Low Output Voltage Make these tests Wi external source connected as d scribed i in step 3 of Table 5 4 Check turn off of Q4 by moment Output voltage remains a Q4 shorted Q7 open arily shorting base 69 to low emitter TP75 Output voltage rises Proceed to step 2 Check turn off of Q12 by moment Output voltage remains Q12 shorted arily shorting base TP83 to low emitter 74 Output voltage rises Proceed to step 3 Isolate fault to constant voltage Output voltage rises Z1 defective strap between A6 and comparator or constant current A7 open R16 R17 shorted comparator by opening the b Output voltage remains Reconnect lead and proceed to cathode of CR4 low step 4 Check turn on of Q5 by moment Output voltage remains Q5 or open Q11 shorted arily shorting base 84 to low collector TP83 Output voltage rises Proceed to step 5 Check turn on of Z1 by moment Output voltage remains 21 defective arily connecting a 10kQ resistor low between 10 TP89 and 6 2V b Output voltage rises b R10 or R11 shorted strap between 2 supply 1P24 and open R9 open C1 shorted
94. ed by the current setting the supply 3 2 MODELS 62568 62648 62678 62748 Al A2 4 7 S A9 5 MODELS 62638 62658 62668 627 8 Al A2 4 A5 5 GND AG 45 Figure 3 2 Normal Strapping Patterns operates in the constant voltage mode With a load resis tance smaller than this critical value it operates in the constant current mode The transition occurs automatis cally no switches need to be operated or connections changed 3 8 Constant Voltage Operation 3 9 To adiust the supply for constant voltage operation a Turn on supply and with output terminals open adjust the VOLTAGE controls for the desired output voltage b Connect a short across the rear panel output terminais output current if change causes this current limit to be exceeded the supply automatically crosses over to constant current operation at this preset current limit and the output voltage drops proportionately In setting the current limit make an adequate allowance for high peak currents that could cause unwanted crossover Refer to paragraph 3 69 3 10 Constant Current Operation 3 11 To adjust the supply for constant current operation a Connect a short across the rear output terminals and adjust the CURRENT controls for the desired output current b Open the output terminals and adjust the VOLTAGE controls for the desired maximum output voltage load change causes this volt
95. ence of flammable gases or fumes KEEP AWAY FROM LIVE CIRCUITS Operating personnel must not remove instrument covers Component replacement and internal adjustments must be made by qualified service personnel Do not replace com ponents with power cable connected Under certain condi tions dangerous voltages may exist even with the power cable removed To avoid injuries always disconnect Power discharge circuits and remove external voltage sources before touching components DO NOT SERVICE OR ADJUST ALONE Do not attempt internal service or adjustment unless another person capable of rendering first aid and resuscitation is present 44 47 at DO NOT EXCEED INPUT RATINGS This instrument may be equipped with a line filter to redute electromagnetic interference and must be connected to a pro perly grounded receptacie to minimize electric shock hazard Operation at line voltages or frequencies in excess of those stated on the data plate may cause leakage currents in excess of 5 0 mA peak Y 3 Bane SSL SAFETY SYMBOLS instruction manual symbol the product N will be marked with this symbol wh n it is necessary for the user to refer tothe instruction manual refer to Table of Contents Indicates hazardous voltages e or tm Indicate earth ground terminal WARNING j 1 1 The WARNING sign denotes hazard It calls attention to a procedure practice or
96. ents BEFORE APPLYING POWER Verify that the product is set to match the available line voltage end the correct fuse is installed GROUND THE INSTRUMENT This product is a Safety Class 1 instrument provided with a protective earth terminal To minimize shock hazard the in strument chassis and cabinet must be connected to an elec tricat ground The instrument must be connected to the ac power supply mains through a three conductor power cable with the third wire firmly connected to an electrical ground safety ground at the power outlet For instruments designed to be hard wired to the ac power lines supply mains connect the protective earth terminal to a protective conductor before any other connection is made Any interruption of the protec tive grounding conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury If the instrument is to be energized via an external autotransformer for voltage reduction be certain that the autotransformer common terminal is connected to the neutral earthed pole of the ac power lines supply mains INPUT POWER MUST BE SWITCH CONNECTED For instruments without a built in line switch the input power lines must contain a switch or another adequate means for disconnecting the instrument from the ac power lines supply mains PU DO NOT OPERATE IN AN EXPLOSIVE ATMOSPHERE Do not operate the instrument in the pres
97. equired to obtain good regulation at the load If the load regulation is critical use remote voltage sensing Refer to paragraph 3 25 3 17 If multiple loads are connected to one supply each load should be connected to the supply s output terrninals using separate pairs of connecting wires This minimizes mutual coupling effects between loads and takes full advantage of the supply s low output impedance Each pair of connecting wires should be as short as possibie and twisted or shielded to reduce noise pickup 3 18 load considerations require the use of output distribution terminals that are located remotely from the suppiy then the power supply output terminals should be connected to the remote distribution terminals by a pair of twisted or shielded wires and each load should be separately connected to the remote distribution terminals Remote voltage sensing would be required under these circumstances Refer to paragraph 3 25 3 19 Either positive or negative voltages can be obtained from this supply by grounding one of the output terminals or one end of the load Always use two wires to connect the load to the supply regardless of where or how the system is grounded Never ground the system at more than 3 3 one point This supply can be operated up to 300 volts above ground if neither output terminal is grounded 3 20 Operation Beyond Rated Output 3 21 The supply may be able to provide voltages and currents greater th
98. er supply and scope appears on the face of the CRT The magnitude of this resulting noise signal can easily be much greater than the true ripple developed between the plus and minus sensing terminals of the power supply and can compietely invalidate the measurement 5 18 The same ground current and pickup problems can exist if an rms voltmeter is substituted for the oscillo scope in Figure 5 2 However the oscilloscope display unlike the true rms meter reading tells the observer immediately whether the fundamental period of the signal displayed is 8 3 milliseconds 1 120Hz or 16 7 milliseconds 1 60Hz Since the fundamental ripple frequency present on the output of an HP supply is 120Hz due to full wave rectification an oscilloscope display showing a 120Hz fundamental component indicates a clean measurement setup while the presence of a SOHz fundamental usually means that an improved setup will result in a more accurate and lower value of measured ripple POWER SUPPLY CASE OSCILLOSCOPE CASE A INACCURATE METHOD USING SINGLE ENDED SCOPE GROUND CURRENT IG PRODUCES 60 CYCLE DROP IN NEGATIVE LEAD WHICH ADDS TO THE POWER SUPPLY RIPPLE DISPLAYED ON SCOPE METHODO MAY BE ADEQUATE UNDER CERTAIN CONDITIONS SEE TEXT POWER SUPPLY CASE OSCILLOSCOPE CASE VERTICAL INPUT B RECOMMENDED METHOD USING A DIFFERENTIAL SCOPE WITH FLOATING INPUT GROUND CURRENT PATH 15 BROKEN COMMON MOOE REJECTION OF DIFFERENTIAL INPUT SCOPE I
99. error voltage which ultimately varies the conduction of the series regulator 4 34 Resistor R1 in series with the summing point Mea input to the differential amplifier limits the current flowing into the differential amplifier during rapid voltage turn down Diode 2 prevents excessive current drain from the 6 2 volt reference supply during rapid down program ming Diodes CR1 and CR2 prevent excessive voltage excursions from overdriving the differential amplifier 4 35 During constant voltage operation the program ming current flowing through the programming resistors VOLTAGE controls is constant because the summing point is held constant at zero volts by feedback action and virtually all of the reference supply current flowing through pull out resistors R9 R12 and R13 flows through VOLTAGE controls R10 and R11 Linear constant voltage programming is thus assured Resistor R13 serves as a trimming adjustment for the programming current flowing through R10 and R11 If the supply is equipped with Option 020 or 040 resistor R121 and potentiometer R122 allow the programming current to be adjusted over a narrow range around its nominal value In practice this adjustment sets the power supply output to exactly the maximum rated voltage when programmed to that level 4 36 Main output capacitor C20 connected across the output terminals of the supply stabilizes the series regulator feedback loop when the normal strapping p
100. g Adjust decade resistance until digital voltmeter reads exactly zero then shunt R28 with fixed metal film 51 1 4 or 1 8 watt resistor of value equal to that of decade box 5 79 Zero Output Current Option 021 or 040 To calibra the zero current programming accuracy of an instrument equipped with Option 021 or 040 proceed as fotlows a Perform steps a through c of paragraph 5 78 b Adjust potentiometer R128 labeled CURRENT ZERO and accessible through hole in rear panel until digital voltmeter reading is zero volts t2mV 5 80 CC Programming Accuracy Standard Instrument To calibrate the constant current programming current of a standard instrument proceed as foliows Connect test setup shown in Figure 5 7 except substitute a short circuit for load resistor b Disconnect jumper between A5 and A6 on rear barrier strip c Connect a 0 1 1 4 watt resistor of the value shown below between terminals A4 and A6 on rear barrier strip 62568 6264B 20022 6263B 6266B 100022 62678 62748 10002 6265B 6271B 9002 d Connect decade resistance box in place of R19 Rotate VOLTAGE controls fully clockwise and turn on supply f Adjust decade resistance until digital voltmeter indicates 500 10 g Replace decade resistance with 5 1 2 watt resistor of appropriate value in R1 9 position 5 81 CC Programming Accuracy Option 021 or 040 To calibrate the constant current programming current of an inst
101. g terminal 4 Notice that the shields at the power supply end of the two coaxcabies not connected to the power supply ground since such a connection would give rise to a ground current path through the coax shield and result in an erroneous measurement SOn TERMINAT POWER SUPPLY T OSCILLOSCOPE CASE CONNECTOR CASE MyerticaL 5 INPUT L vERTICA O Otuf 1 L gt son T CONNEC TOR i son TERMINATION Figure 5 3 Noise Spike Measurement Test Setup s 5 Since the impedance matching resistors constitute a 2 to 1 attenuator the noise spikes observed on the oscillo scope should be less than 10mV p p for the Model 6274B or less than 5mV p p for the other models 5 26 The circuit of Figure 5 3 can also be used for the normal measurement of low frequency ripple Simply remove the four terminating resistors and the blocking capacitors and substitute a higher gain vertical plug in for the wide band plug in required for spike measurements Notice that with these changes Figure 5 3 becomes a two cable version of Figure 5 28 5 27 Load Transient Recovery Time Definition The time for output voltage recovery to within Y of the nominal output voltage following Z amp step change load current where Y is specified as 10mV the nominal output voitage is defined as the dc level halfway between the static output voltage before and after the imposed load chang
102. g terminals S and S are inadvertently removed 4 70 Diode CR11 previously mentioned the series regulator description protects the regulating transistor from reverse voltages E SECTION V MAINTENANCE 5 1 INTRODUCTION graph 5 60 perform any necessary adjustments and calibrations paragraph 5 62 Before returning the power 52 Upon receipt of the power supply the performance supply to normal operation repeat the applicable portions test paragraph 5 5 should be made This test is suitable of the performance test to ensure that the fault has been for incoming inspection fault is detected in the power properly corrected and that no other faults exist Before supply while making the performance test or during normal performing any maintenance checks turn on the power operation proceed to the troubleshooting procedures supply and allow a half hour warm up paragraph 5 49 After troubleshooting and repair para Table 5 1 Test Equipment Required RECOMMENDED MODEL REQUIRED CHARACTERISTICS HP 34508 Measure dc voltages calibration procedures Sensitivity 100uV full scale min Input impedance 10 22 min Digital Voltmeter HP 180C with 1821A time base and 1806A vertical plug in 1803A plug in for spike measurement Measure ripple display transient recovery waveform measure noise spikes Sensititivy and bandwidth 100uV cm and 400kHz for al
103. ghout the manual Option No Description 005 Realignment for 50Hz Operation Standard instruments are designed for 57 to 63Hz operation For 50Hz operation several resistors in the preregulator control circuit are changed in value and the preregulator is realigned 007 008 009 010 013 014 020 021 022 027 Ten Turn Output Voltage Control A ten turn control repiaces the coarse voltage control for improved resolution in setting the output voltage Ten Turn Output Current Control ten turn control replaces the coarse current control for improved resolution in setting the output current Ten Turn Output Voltage and Current Controls This option includes Options 007 and 008 in the same instrument Chassis Slides Factory installed slides permit convenient access to the interior of a rack mounted supply for maintenance Three Digit Graduated Decadial Voltage Control To improve mechanical stability and permit accurate resetting of the output voltage Option 013 replaces the coarse voltage control with a ten turn control equipped with a 3 digit turns counting diai Three Digit Graduated Decadia Current Control To improve mechanical stability and permit accurate resetting of the output current Option 014 replaces the coarse cur rent control with a ten turn control equipped with a 3 digit turns counting dial Adjustable Voltage Programming Two screwdriver adjustable controls mounted on
104. gramming resistor x Any of the supplies included in this manual can be used as an auto tracking slave and any well reguiated variabie output supply be used as the master 3 61 Determining the Value for Ry Each slave supply has an external resistor Ry associated with it that supplies its voltage programming current the temperature coefficient and stability specifications of the supplies are to be maintained these must be stable low noise resistors with a temperature coefficient of less than 30ppm per and a power rating at least 30 times what they will actually dissipate To calculate the proper value for Ry for each slave the following information is required a the rated maximum voltage of the master supply b the corresponding maximum voltage desired of the slave supply with its voltage control set to maximum c Rp the resistance of the slave supply s coarse voltage control The Rp values for the supplies included in this manual are as follows Model 62568 2 5k22 6263 62648 5kQ 62658 62668 62678 10 2 62718 62748 20kQ To find Ry use the formula For example if the slave supply is a Model 6263B and we want its cutout to vary from zero to 1n volts as the master wir supply varies from zero to 40 volts the solution for Ry is Ry 40V x 5 2 10 5kQ Ry 15 3 62 It is also possible to make an auto tracking slave s voltage equal
105. he load on the programming voltage source is less than 20 microamperes The programming voitage required to obtain maximum rated current from these supplies is about 500 millivoits An input greater than 600mV may damage the instrument through excessive power dissipation Impedance matching resistor Ry is required to maintain the temperature coefficient and stability specifications of the supply 3 43 Auto Parallel Operation 3 44 Use the rear panel and circuit board interconnec tions shown in Figure 3 8 or 3 9 to auto parallel two or three supplies This mode of operation provides a greater current Capacity than can be obtained from a single supply while maintaining nearly equal load sharing among the paralleled supplies under all load conditions Supplies having the same model number make the most practical auto parallel combinations but any of the supplies included in this manual that have equal current ratings may be used 3 7 NOTE Use wires of equal length and gauge to connect each auto paralleled supply to the load Load sharing accuracy is affected unless the positive leads connecting each supply to the load are all equal in resistance 3 45 Setting the Voltage and Current Controls The auto parallel combination of two or three supplies behaves as if it were a single constant voltage constant current supply controlled by the voltage and current controls of the master supply The voltage controls of the slave s are disabled
106. he output When 57 fires overvoltage lamp DS2 turns on completing a path for a 12V unregu lated holding current through DS2 R101 supplies the holding current if lamp DS2 should open This current holds CR57 on even after the output voltage has fallen CR57 remains in conduction until the supply is turned off R102 protects CR56 and CR57 from the large surge current that occurs when CR57 is first fired CR58 damps out negative overshoot in the trigger pulse 4 52 The firing of CR57 biases 023 into conduction This places approximately 12 volts on the cathode of 44 in the preregulator control circuit to reverse bias CR43 and CR44 By preventing transistor Q19 from turning off this prevents the generation of any trigger pulses and turns off the preregulator 4 53 The crowbar circuit creates an extra current path during normal operation of the supply thus changing the current that flows through the sampling resistor Diode 9 keeps this extra current at fixed level for which compensation can then be made in the constant current comparator circuit 4 54 A slaving arrangement for the crowbar circuits in more than one supply is made possible by an extra secondary winding terminals 5 and 6 on 4 When units have these windings connected in parallel their crowbars are activated if any one of the crowbars is tripped To reset the crowbars in this arrangement all of the units must be turned off and then on Polarity must
107. he sensing leads are part of the supply s program ming circuit so they should be connected in such a way as to make it unlikely that they might inadvertentiy become open circuited If the sensing leads were to open during operation the output voltage would tend to rise Although the increase would be limited by protective resistors R58 and R59 damage to the supply or to the load might occur if the loss of sensing were accompanied by a load transient For this reason no switch relay or connector contacts should be included in the remote sensing path CAUTION When using remote voltage sensing it is possible to damage the supply by disconnecting a load lead while the sensing lead is still connected and the supply is energized If a load lead becomes disconnected current flows through internal protection resistors R58 and R59 the sensing leads and the load and may burn out the resistors Additional factors could compound the damage caused by an opened load lead If the output of the supply is connected to an inductive load or a battery or is connected in parallel with another supply then opening a load lead would allow current from the external source to flow through the sensing leads and damage the supply s input circuits If the crowbar fires the damage could even be greater For these reasons if there is any risk o an opened load circuit while remote sensing is used 1 16 amp fuses should be installed in both sens
108. ia For more information c call your local HP Sales Office isted telephone directory white pages Ask for the a Or cont ct United States ELM gue 98 Hewlet a card Company ie 3 a T Hewlett Packard Conipany ORE 52010 vie Drive P ev SIDE Rolling Mesdows IL 60008 812 457 9600 Q8 pe ae HewletPack sd ou one sors 24 qe nt Canada lt a be t Hewlett Packard Ld ue PUE Dm 4 T FEM H UL 6877 Goreway Drive 7 Nen inp Lat vse E Mississauga T 416 678 9430 Australia New Zealand e Hewlett Packard Australia Ltd 31 41 Joseph Street 832855 aropEurope Bur European S A 27 du Nant P mi ER Meyin Switzerland LE Central H ng Kong 3487777 ME Japan Yokogawa Hewlett Packard Lid 15 7 Nishi Shinjuku 4 Chome Shinjuku ku Tokyo 166 Japan Latin America Latii Americar Region Headquarters P lyoux Nbr 111 Lors De Chapultepec 11000 Mexico DF 6257 202 0155 2 Middle East and Africa Geneva Switzerland Tm 4 227 780 7111 E Forall cther ereas Hewlett Packard Intercontinerital Headquarters 53495 Deer Creek Road Palo ud
109. ing leads Fuses in the sensing leads will not affect the performance of the supply and should protect against costly damage Remote sensing is not recommended when charging or discharging a battery See paragraphs 3 79 and 3 83 3 31 Another factor to be considered when making a remote sensing installation is the inductance of the long toad ieads Aithough dc and iow frequency performance are improved by remote sensing the higher inductance of longer leads does impair transient response and could affect the stability of the feedback loop seriously enough to cause oscillation Disconnecting the supply s output capacitor and connecting a similar capacitor directly across the oad helps to overcome these problems Disconnect output capacitor C20 by removing the rear panel jumper from between terminals and 8 and connect another capacitor having approximately the same capacitance an equal or greater voltage rating and good high frequency characteristics across the load using short leads it may also be beneficial to readjust transient recovery control R30 located on the main circuit board 3 32 Remote Programming 3 33 The output voltage or current of these power supplies can be remotely controlled by connecting an external resistor or applying an external voltage to rear panel terminals If resistance programming is used a variable resistor can control the output over its entire range or by being connected in series wi
110. input signals applied to its emitter Resistor R86 connected between the negative output line and the emitter of Q22 furnishes a signal pro portional to the output voltage Resistors R87 and R79 sample the voltage across and the current through the series regulator Resistors R74 and R75 are the source of a constant offset current to the summing point which en sures that the triac will fire at low output voltages Capaci tor C17 and resistor R78 stabilize the entire preregulator feedback loop 4 23 The summation of these input signals results in a voltage waveform at TP73 similar to that shown in wave form A of Figure 4 4 When the linear ramp portion of the waveform reaches a certain negative threshold diodes CR43 and CR44 become forward biased These diodes couple a negative voltage to the base of transistor 019 Transistors Q19 and Q18 form a bistable circuit similar to Schmitt trigger Prior to firing time Q19 is conducting due to the positive bias supplied to its base through R73 and transistor Q18 is cut off because its base is driven negative by the collector of Q19 4 24 When the negative threshold voltage is reached transistor Q19 is turned off and Q18 is turned on The conduction of 018 allows capacitor to discharge rapidly through pulse transformer T3 generating a firing pulse across the secondary of Diode CR40 blocks any positive overshoot 4 25 The control circuit is reset once every 8 33 milli
111. ion Zero current output 020 or 040 R25 or R28 or R128 if Option 021 or or 040 See para 5 70 and 5 77 Q3 O4 Q12 Driver and error amplifiers CV CC load regulation Q5 011 Mixer amplifier CV CC load regulation CV transient response R30 See para 5 82 09 014 Reference reguiator 1 2 4 reference voitage constant voitage line 015 016 ae Voltage clamp circuit CC load regulation 018 019 R75 R78 See 022 5 84 5 86 023 024 Crowbar Trip voltage voltage across series regulator when R108 R109 See Q25 tripped para 5 88 and 5 90 CR1 CR2 Limiting diodes CV load regulation stability as gate and limiting diode CV CC load regulation Eu 5 13 Output voltage ripple imbalance and preregulator waveforms Preregulator control Table 5 8 Checks and Adjustments Required After Semiconductor Replacement Continued REFERENCE Temperature stabilizing CR6 CR46 diodes CR7 CR20 12 4 and 6 2 reference voltages CRO CR56 CR60 FUNCTION OR CIRCUIT ADJUST Temperature coefficient R108 R109 See para 5 88 and 5 90 Trip voltage voltage across series regulator when crowbar is tripped supply stability Crowbar CR10 12 144 Rectifier diodes CR21 24 27 CR28 31 33 Voltage across appropriate filter capacitor
112. isabling The Crowbar 5 93 To disable the crowbar completely disconnect the cathode of CR57 This can be easily accomplished by removing the jumper connecting the cathode to the printed circuit board This jumper is accessible from the component top side of the board 5 18 SECTION VI REPLACEABLE PARTS 6 1 INTRODUCTION 2 This section contains information for ordering re placement parts Table 6 3 lists parts in alpha numeric order by reference designators and provides the following informa tion a Reference Designators Refer to Table 6 1 b Description Refer to Table 6 2 for abbreviations c Manufacturer s Part Number or Type d Manufacturer s Federal Supply Code Number Refer to Table 6 3 for manufacturer s name and address e Hewlett Packard Part Number f Parts not identified by a reference designator are listed at the end of Table 6 3 under Mechanical and or Miscellaneous The former consists of parts belonging to and grouped by individual assemblies the latter consists of all parts not immediately associated with an assembly 6 3 ORDERING INFORMATION 6 4 To order a replacement part address order or in quiry to your local Hewlett Packard sales office see lists at rear of this manual for addresses Specify the following information for each part Model complete serial number and any Option or special modification J numbers of the instrument Hewlett Packard part number circuit reference designato
113. ive voltage The crossover from constant voltage to constant current operation or vice versa occurs automatically when the load current reaches the value established by the current controls or the voltage reaches the value established by the voitage controis The output voltage and current can both 1 4 Output loads are further protected by a builtin fast acting overvoltage protection crowbar circuit that automatically shorts the supply s output terminals i a preset voltage limit is exceeded A front panel control sets the voltage at which the crowbar trips and can be adjusted from approximately 1096 to 11096 of the supply s maximum rated voltage When several supplies are installed in the same system whether in series parallel or independently their crowbar circuits can be interconnected so that all will trip simultaneously whenever any one of them does 1 5 The Mode 6274B supply is forced air cooled the other models covered by this manual are cooled by convec tion 1 6 The ac input connections to the supplies in 5 1 4 inch cabinets are made at rear panel terminals the 3 1 2 inch units are equipped with 3 wire line cords Ail dc out put remote sensing and remote programming connections 1 1 arrere MODELS 62568 62648 62678 made at rear pane terminals The output terminals on the front panel are for monitoring purposes only and rated at 3 amps maximum Either the positive
114. l measurements except noise spike 5mV sensitivity and 20MHz bandwidth for noise spike measurement Oscilloscope Range 90 130 volts Output current 20096 min of supply input current listed in para 2 16 Variable Voltage Transformer Vary ac input for line regulation measurement HP 3490A or HP 427A Measure ac and dc voltages resistance Digital or Analog Multimeter Switching rate 60 400Hz Rise time 2usec Measure transient recovery time Repetitive Load Switch Power supply load resistor Resistive Values see Figures 5 1 and 5 4 Load Current Sampling Resistor Measure output current calibrate ammeter Value see Figure 5 7 Value 50 ohms 1 2 watt 55 non inductive Four required Noise spike measurement Terminating Resistors Value 0 01uF 100Vdc Two required Noise spike measurement Blocking Capacitors 5 3 TEST EQUIPMENT REQUIRED 5 4 Table 5 1 lists the test equipment required to perform the procedures described in this section 5 5 PERFORMANCE TEST 5 6 The following test be used as an incoming inspection check Appropriate portions of the test can be repeated either to check the operation of the instrument after repairs or for periodic maintenance tests The tests are performed using a 115 Vac 60Hz single phase input
115. led by a single fan 6264B 6265B OPTIONS AVAILABLE 6266B Options 005 007 008 009 010 013 014 020 021 6267B 022 027 028 and 040 See paragraph 1 10 for descrip 6271B tions 62748 DIMENSIONS See Figure 2 1 outline diagrams Net 35 Ibs 15 8kg 34 Ibs 15 4kg 47 Ibs 21 3kg 34 Ibs 15 4kg 34 165 15 4kg 39 Ibs 17 7kg 34 Ibs 15 4kg 48 Ibs 21 7kg the rear panel The Models 6263B 6265B 6266B and 6271 are equipped with a 5 foot 3 wire line cord Shipping 40 Ibs 18 1kg 41 Ibs 18 6 9 54 tbs 24 5kg 41 Ibs 18 6kg 41 155 18 6kg 46 Ibs 20 8kg 41 155 18 6kg 54 Ibs 24 5kg SECTION ti INSTALLATION 2 1 INITIAL INSPECTION 2 2 Before shipment this instrument was inspected and found to be free of mechanical and electrical defects As soon as the instrument is unpacked inspect for any damage that may have occurred in transit Save all packing materials until the inspection is completed if damage is found file a claim with the carrier immediately The Hewlett Packard Sales and Service office should be notified as soon as possible 2 3 Mechanical Check 2 4 This check should confirm that there are no broken knobs or connectors that the cabinet and panel surfaces are free of dents and scratches and that the meter is not scratched or cracked 2 5 Electrical Check 2 6 The instrument should be checked against its electrical specifications Section V includes an in cabinet
116. llimantic Conn Dialight Corp Brooklyn N Y General instrument Corp Newark N J Drake Mfg Co Harwood Heights Elastic Stop Nut Div of Amerace Esna Corp Erie Technological Products Union N J Erie Hart Mfa Co Beckman Instruments Fullerton Calif Fenwal Inc Ashland Mass Hughes Aircraft Co Electron Dynamics Div Torrance Calif Amperex Electronic Hicksville N Y Bradley Semiconductor Corp New Haven Conn Carling Electric Inc Hartford Conn Federal Screw Products Inc Chicago Heinemann Electric Co Trenton N J Hubbell Harvey Inc Bridgeport Conn Amphenol Corp Amphenol RF Div Danbury Conn E F Johnson Co Waseca Minn Hartford Conn 75376 75382 75915 76381 76385 76487 76493 76530 76854 77068 77122 77147 77221 77252 77342 77630 77764 78189 78452 78488 78526 78553 78584 79136 79307 79727 79963 80031 80294 81042 81073 81483 81751 82099 82142 82219 82389 82647 Use Code 71785 assigned to Cinch Mfg Co Chicago lil Table 6 3 Code List of Manufacturers ADDRESS IRC Div of TRW Inc Philadelphia Pa Howard B Jones Div of Cinch Mfg Corp New York N Y Kurz and Kasch Inc Dayton Ohio Kilka Electric Corp Mt Vernon N Y Littlefuse Inc Des Plaines Minnesota Mining and Mfg Co St Paul Minn Minor Rubber Co
117. llows a Connect oscilloscope or rms voltmeter as shown in Figures 5 2A or 5 2B b Turn CURRENT controls fully clockwise Turn on supply and adjust VOLTAGE controls unti front panel meter indicates maximum rated output voltage d The observed ripple should be less than All models except 62748 200 rms 10mV 6274B 200uV rms 20mV 5 24 Noise Spike Measurements An instrument of sufficient bandwidth must be used when making a high frequency spike measurement An oscilloscope with a bandwidth of 20MHz or more is adequate Measuring noise with an instrurnent that has insufficient bandwidth may conceai high frequency spikes that could be detrimental to the load 5 25 The test setup illustrated in Figure 5 2 is not adequate for measuring spikes a differential oscilloscope is necessary Furthermore the measurement technique of Figure 5 2A must be modified as follows if accurate spike measurement is to be achieved 1 As shown in Figure 5 3 two coax cables must be substituted for the shielded two wire cable 2 Impedance matching resistors must be included to eliminate standing waves and cable ringing and capacitors must be connected to block dc current 3 The length of the test leads outside the coaxis critical and must be kept as short as possible The blocking capacitor and impedance matching resistor should be connected directiy from the inner conductor of the cabie to the power supply sensin
118. ly operates in the constant current mode delivering the current set by the current control This con stant current flowing through dropping resistor Ry produces a constant voltage across the resistor initially the battery voltage is high and the supply s output voltage is low but as the battery voltage decreases during discharge the supply voltage increases When the battery voltage reaches zero the supply senses this through the connection to its A2 terminal and reduces the output current to Zero As shown in Figure 3 15 Ry must be selected so that its drop is less than the maximum rated output voltage of the supply but greater than the initial battery voltage 3 86 To give a battery a constant current discharge proceed as follows a Turn off the power supply and disconnect the jumpers from terminal A1 to A2 and from A2 to This step disables the supply s VOLTAGE controls 3 15 b Connect terminal A3 to S and leave ali other jumpers connected as for normal operation as shown in Figure 3 15 C Connect the negative terminal of the battery to A2 through a 10k22 resistor d Connect the negative terminal of the supply to the positive terminal of the battery Connect x between the positive terminal of the supply and the negative terminal of the battery rotate the supply s current control fully counterclockwise CCW energize the supply and set the current control for the desired discharge
119. mize dissipation in the series regulator transistors 4 3 To accomplish this the preregulator control circuit issues a phase adjusted firing to the triac once during each half cycle of the ac input The control circuit continuously samples the input line voltage the dc input to the series regulator and the voltage across the series regulator On the basis of these inputs it controls the time at which each firing pulse is generated 4 4 The output of the triac preregulator is stepped down by the power transformer fuil wave rectified and filtered The resulting preregulated dc voltage is applied to the series regulator which varies its conduction to provide a regulated voltage or current at the output terminals 4 5 The series regulator is part of another feedback loop which consists of the error and driver amplifiers the constant voltage comparator and the constant current comparator The series regulator feedback ioop makes rapid low magnitude adjustments to the output while the preregulator feedback loop handles large relatively slow regulation demands 4 6 feedback signals that control the conduction of the series regulator originate in the constant voltage or constant current comparator During constant voltage operation the constant voltage comparator compares the output voltage of the supply with the drop across the VOLTAGE controls f these voltages not equal the comparator produces an error signal
120. n 20 microamperes Impedance matching resistor R X is required to maintain the temperature coefficient and stability specifications of the supply 3 A0 Constant Current Output Resistance Input The rear panel connections shown in Figure 3 6 allow the output 3 6 current to be varied by using an external resistor to program the supply The supply s constant current programming current which is factory adjusted to 0 5 210 deter mine the exact value of its programming coefficient The programming coefficients for the supplies included in this manual are as follows Models 6256 62648 10 ohms ampere 6263 62678 100 ohms ampere 6265B 6271B 300 ohms ampere 62668 200 ohms ampere 62748 67 ohms ampere if the 10 accuracy of these coefficients is not adequate they may be adjusted either by changing resistor R19 as discussed in paragraph 5 80 or if the instrument is equipped with Option 021 or 022 by adjusting potentiometer R126 as discussed in paragraph 5 81 3 41 With zero ohms placed across the programming terminals the output current of the supply may be set to exactly zero either by changing resistors R25 and R28 as described in paragraph 5 78 or if the insturment is equipped with Option 021 or 022 by adjusting potentiometer R128 as discussed in paragraph 5 79 CAUTION Do not allow programming terminals 4 and A6 to become open circuited while resistance programming the output current If they
121. nce by the Customer Customer supplied software or interfacing unauthorized modification or misuse operation outside of the environmental specifications for the product or improper site preparation and maintenance NO OTHER WARRANTY IS EXPRESSED OR IMPLIED HP SPECIFCALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE E 10 0001055 7 EXCLUSIVE REMEDIE E AND EXLCUSIVE REMEDIES HP SHALL NOT BE LIABLE FOR ANY DIRECT INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES WHETHER BASED ON CONTRACT TORT OR ANY OTHER LEGAL THEORY 75 ASSISTANCE The above statements apply only to the standard product warranty Warranty options extended support contracts pro duct maintenance agreements and customer assistance agreements are also available Contact your nearest Hewlett Packard Sales and Service office for further information on HP s full line of Support Programs nN e eres ne Aa Re SAFETY SUMMARY The following general safety precautions must be observed during all phases of operation service and repair of this instra ment Failure to comply with these precautions or with specific warnings elsewhere this manual violates safety standards of design manufacture and intended use of the instrument Hewlett Packard Company assumes no liability for the customer s failure to comply with these requirem
122. nd 3 13 show the rear panel inter connections required to operate two or three supplies in the auto tracking mode This mode of operation allows two or three supplies that share a common negative output bus to power separate loads and have their outputs simultaneous ly programmed by the voltage and current controls of a master supply Untess their outputs are to be equal the supply that is to have the greatest output voltage must be selected as the master The output voltage of each slave remains a constant percentage of the master s with the percentage for each slave established by that voltage control settings and the choice of its MODELS 62565 62648 62678 62748 2 4 5 A6 5 AS 5 MODELS 62638 62658 62668 62718 AL A2 A3 A4 AS AB AT 5 5 Figure 3 10 Auto Series Operation of Two Units av MODELS 62568 62648 62678 62748 A 2 A3 4 5 S A9 5 CROWBAR eee 21010 212 1 t 2 MODELS 62638 62658 62668 627 8 Al 2 A4 5 6 5 lelelelelelelele e elelelele o sre wr o R PR MT MUS EECEHEEEEBEEE Ag A4 AS S GNDAB 5 2 A4 5 S GNDAB 5 444242914421221012 Figure 3 11 Auto Series Operation of Three Units 3 11 external pro
123. nnections and make certain all wires and straps are properly connected and terminal strip screws are securely tightened before reapplying power 3 25 Remote Voltage Sensing 3 26 Because of the unavoidable voltage drop developed in the load leads the normal strapping pattern shown in Figure 3 2 will not provide the best possible voltage regu lation at the load If for example one were to use 8 gauge wire to connect a load that is located only 5 feet from a Model 6256B 10V 20A supply the regulation measured at the load would be about 120 millivolts as compared to the 1 2 millivolt regulation that could be measured at the supply s output terminals Thus even relatively short load leads can cause a considerable degradation of the supply s performance The remote sensing connections shown in Figure 3 3 improve the voltage regulation at the load by monitoring the voltage there instead of at the supply s output terminals The advantages of remote sensing apply only during constant voltage operation This is because in the constant current mode the resistance of the load leads has no adverse effect on a supply s performance 3 27 As can be seen in Figure 3 3 remote sensing involves removing the S and S jumpers from the rear panel terminals connecting the load leads normally and using a separate pair of wires to connect the 5 and S sensing terminals to the load The following para graphs discuss sorne precautions that shoul
124. ntil voltmeter reading varies between 3 1 and 4 3Vdc Replace decade box with equivalent resistor 5 88 Crowbar Trip Voltage Adjustment 5 89 To adjust the voltage at which the crowbar fires proceed as follows a Turn front panel OVERVOLTAGE ADJUST potentiometer R109 fully clockwise b Turn on supply c Set output voltage to desired trip voltage d Turn R109 slowly counterclockwise unti the crowbar fires amber OVERVOLTAGE lamp lights and voltmeter indication talis to 2670 e Turn off supply and turn down output voltage controis Turn supply and set desired output voltage NOTE It is recommended that the crowbar trip voltage be set higher than the normal output voltage by no less than 7 of the desired output voltage plus one volt in order to avoid false tripping of the cro 5 90 Maximum Crowbar Trip Voltage Adjustment 5 91 To adjust the maximum voltage at which the crowbar fires proceed as follows a Rotate R109 OVERVOLTAGE ADJUST and CURRENT controls fully clockwise b Connect decade resistance box in place of R108 5 17 Turn on supply and adjust VOLTAGE controls for tput voltage as follows 62568 12Vdc 6263B 6264B 23V dc 62658 62668 62678 45Vdc 62718 62748 66Vdc d Adjust decade resistance box until crowbar fires e Replace decade resistance with appropriate value resistor in R108 position Maximum crowbar trip voltage is now set at voltage given in step c 5 92 D
125. o 20MHz TEMPERATURE COEFFICIENT Constant Voltage Less than 0 01 plus 200uV change in output per degree Celsius change in ambient following a 30 minute warmup Constant Current Models 62568 62638 62648 and 62748 Less than 0 0196 plus 2mA change in output per degree Celsius change in ambient following a 30 minute warmup Models 6265B 6266B 6267B and 6271B Less than 0 01 plus 1mA change in output per degree Celsius change in ambient following a 30 minute warmup Table 1 1 Specifications Models 6256B 6263B 6264B 6265B 6266B 6267B 6271B and 6274B continued DRIFT STABILITY Change in output dc to 20Hz over an 8 hour interval under constant line load and ambient temperature follow ing a 30 minute warmup Constant Voltage Less than 0 0396 of output plus 500uV except for the Models 62678 and 62748 which have a drift of less than 0 03 of output plus 2mV Constant Current Models 6256B 6263B and 6264B Less than 0 03 of output plus 6mA Models 6265B 6266B 6267B and 6271B Less than 0 0396 of output plus 3mA Model 6274B Less than 0 03 of output plus 5mA RESOLUTION Minimum output voltage or current change that can be obtained using the front panel controis Model Constant Voltage 6256B 62638 62648 6265B 6266B 6267B 62718 62748 1 2mV 2mV 5mV 5mV 5mV 10 10mV C
126. oltage Control 1 W V 1V N 1V V 1V V 1V V 1V V Voltage Control 10 167 100mV A 50mV A 167mV A 25 50mV A 25mV A 33 3mV A Typical time required to nonrepetitively change from zero to within 99 996 of the maximum rated output voltage or from the maximum rated output voltage to within 0 176 of that voltage above zero Modei 6256B 6263B 6264B 6265B 6266B 62678 62718 62748 62568 62638 62648 62658 62668 62678 62718 62748 60ms 150ms 140ms 275ms 275ms 275ms 600ms 600ms Up No Load 60ms 150ms 140ms 275ms 275ms 275ms 600ms 600ms Up Load Q 5 2 ni r C Down No Load 5 sec 7 sec 10 sec 12 sec 13 sec 13 sec 7 sec 40 sec Table 1 1 Specifications Models 6256B 62638 6264B 6265B 6266 6267B 6271B and 6274 continued PANEL METERS INPUT POWER CONNECTIONS The accuracy of the front panel voltmeter and ammeter In the Models 62568 62648 62678 and 62748 input is 2 of full scale The ranges of these meters are power s connected by way of a 3 terminal barrier strip on Model 62568 12V 24A Model 62668 50V 6A 6263B 24V 12A 6267 50V 12A 6264B 24V 24A 6271B 70V 4A 6265B 50V 4A 6274B 70V 18 TEMPERATURE RATINGS Operating 55 WEIGHT Storage 40 to 75 C Mode COOLING 6256B Convection cooling is used except the Model 62748 6263B which is forced air coo
127. oltmeter over the stated measurement interval A strip chart recorder can be used to provide a permanent record Place a thermometer near the supply to verify that the ambient temperature remains constant during the period of measurement The supply should be located away from any source of stray air currents If possible place the supply in an oven and hold it at a constant temperature Take care that the measuring instrument has an eight hour stability at least an order of magnitude better than the stability specification of the power supply being tested Typically a supply wil drift less over the eight hour measurement interval than during the half hour warm up period 5 37 To check the output stability proceed as follows a Connect load resistance and digital voltmeter as itiustrated in Figure 5 1 b Turn CURRENT controls Tully clockwise c Turn on supply and adjust front panel VOLTAGE controls until digital voltmeter indicates maximum rated output voltage d Allow 30 minutes warm up then record digital voltmeter reading e After 8 hours digital voltmeter reading should not differ from the step d reading by more than 6256B 3 5mV 62638 62648 6 5mV 6265 62668 12 5mV 6267 14mV 62718 18 5mV 6274B 20mV 5 38 CONSTANT CURRENT TESTS 5 39 The instruments methods and precautions for the proper measurement of constant current power supp characteristics are for the most part identical to those already described f
128. omerville N J Semiconductor Products Dept Syracuse N Y Eldema Corp Compton Calif Transitron Electronic Corp Wakefield Mass Pyrofilm Resistor Co Inc Cedar Knolls N J Arrow Hart and Hegeman Electric Co Hartford Conn ADC Electronics inc Harbor City Calif amp Burns Mfg Co Inc Mineola Hewlett Packard Co Palo Aito Div Palo Alto Calif Motorola Semiconductor Prod tnc Phoenix Arizona Westinghouse Electric Corp Semiconductor Dept Youngwood Pa Ultronix Inc Grand Junction Colo Wakefield Engr Inc Wakefield Mass General Elect Co Electronic Capacitor amp Battery Dept Irmo S C Bassik Div Stewart Warner Corp Bridgeport Conn IRC Div of TRW Inc Semiconductor Plant Lynn Mass Amatom Electronic Hardware Co inc New Rochelle Beede Electrical Instrument Co Penacook N H General Devices Co Indianapolis ind Semoor Div Components Inc Phoenix Arizona Robinson Nugent Inc New Albany N Y Torrington Mfg Co Van Nuys Calif 6 2 07933 08484 08530 08717 08730 08806 08863 08919 09021 09182 09213 09214 09353 09922 11115 11236 ADDRESS CODE MANUFACTURER Westinghouse Electric Corp Elmira N Y Fairchild Camera and Instrument Mountain View Calif Birtcher Corp The 105 Angeles Calif Sylvania Electric Prod Inc Mountainview Calif IRC Div of TRW inc Burlington
129. onstant Current 20mA 10mA 20mA 3mA 5mA 10mA 3mA 15mA OUTPUT IMPEDANCE TYPICAL Approximated by a resistance in series with an inductance as follows Model 6256B 62638 62648 62658 2 0 552 1 0 2m2 14H 2m82 1uH Model 62668 1 62678 0 57153 1uH 62718 SmQ 1uH 62748 1 1uH LOAD TRANSIENT RECOVERY TIME Less than is required for output voltage recovery lin constant voltage operation to within 10mV of the nominal output following a change in output current equal to the current rating of the supply or 5 amps whichever is smaller OVERVOLTAGE PROTECTION CROWBAR To avoid false tripping the recommended trip margin above the output voltage is 596 of the output voltage plus 1 volt The approximate crowbar trip voltage ranges are Model 62568 2V 12V 6263B 2V 23V 6264B 2 5V 23V 6265B 2 5V 45V Model 6266B 2 5V 45V 6267B 2 5V 45V 62716 6V 66V 6274B 6 66 REMOTE PROGRAMMING CO Output Voltage Programming Resistance Control 51 Mode 62568 6263 62648 62658 62668 62678 62718 62748 Output Current Programming Resistance Control 10 Model 6256B 6263B 62648 62658 62668 62678 6271 62748 REMOTE PROGRAMMING SPEED 20082 V 20082 V 20022 V 20082 V 20082 V 20022 V 30082 V 30082 V 100 1009 1012 A 30012 A 2009 10082 A 30022 A 679 rrivci V
130. or the measurement of constant voltage characteristics There are however two main differences First the power supply performance will be checked between short circuit and full load rather than open circuit and full load Second a current monitoring resistor is inserted between the output of the power supply and the load 5 40 For al output current measurements the current sampling resistor must be connected as a four terminal device in the same manner as a meter shunt would be The load current is fed to the extremes of the wire leading to the resistor while the sampling terminals are located as close as possible to the resistance element itself see Figure 5 6 Acurrent sampling resistor should have low noise low temperature coefficient less than C and should be used at no more than 596 of its rated power so that its temperature rise will be minimized NOTE in case of difficulty obtaining a low resis tance high current resistor suitable for current sampling a duplicate of the sampling resistor used in this unit R54 may be obtained from the factory 5 41 Current Output and Ammeter Accuracy To check that the supply will furnish its rated output current proceed as follows a Connect test setup shown in Figure 5 7 b Turn VOLTAGE controls fully clockwise c Turn on supply and adjust CURRENT controls until front panel ammeter indicates maximum rated output current d Digital voltmeter should read 0 5 0
131. p and disconnect jumper between A1 and 2 6256B 20100 6263B 62648 40102 62658 62668 6267B 80102 62718 6274B 180702 b Connect a digital voltmeter between the S and S terminals c Rotate CURRENT controls fully clockwise and turn on supply d Adjust potentiometer R122 labeled VOLTAGE PROG and accessible through hole in rear panel until digital voltmeter indicates full rated output voltage X0 196 5 16 5 77 Constant Current Programming Calibration 5 78 Zero Output Current Standard Instrument To calibrate the zero current programming accuracy of a standard instrument proceed as follows a Connect test setup shown in Figure 5 7 except substitute a short circuit for load resistor b If unit is to be used in local programming mode turn CURRENT controls fully counterclockwise unit is to be used in remote programming mode connect remote programming setup Figure 3 6 or 3 7 and adjust remote resistance or voltage to zero c Rotate VOLTAGE controls fully clockwise and turn on supply d Observe digital voltmeter reading If reading is more positive than 0 volts shunt resistor R25 with decade resistance box e Adjust decade resistance until digital voltmeter reads exactly zero then shunt R25 with fixed metal film 21 1 4 or 1 8 watt resistor of value equal to that of decade resistance f If reading of step d is more negative than volts shunt resistor R28 with decade resistance box
132. pe of Figure 5 2A might be adequate to eliminate extraneous ripple components so that a satisfactory measurement can be obtained However in stubborn cases or in Measurement situations where it is essential that both the power supply case and the oscilloscope case be connected to ground if both are rack mounted for example it may be necessary to use a differential scope with floating input as shown in Figure 5 2B If desired two single conductor shielded cables may be substituted in place of the shielded two wire cable with equal success Because of its common mode rejection a differential oscilloscope displays only the difference in signal between its two vertical input terminals thus ignor ing the effects of any common mode signal produced by the difference in the ac potential between the power supply case and scope case Before using a differential input scope however it is imperative that the common mode rejection capability of the scope be verified by shorting together its two input leads at the power supply and observing the trace on the CRT If this trace is a straight line then the scope is properly ignoring any common mode signal present If this trace is not a straight line then the scope is not rejecting the ground signal and must be realigned in accor dance with the manufacturer s instructions so that proper common mode rejection is attained 5 23 Ripple Measurement Procedure To check the ripple output proceed as fo
133. perator position am Arbeitsplatz normal operation normaler Betrieb 150 7779 nach DIN 45635 T 19 No fan installed Kein Ventilator eingebaut TE HP Model6274B LpA lt 70 dB LpA 70 dB operator position _ am Arbeitspiatz normal operation normaler Betrieb per ISO 7779 nach DIN 45635 19 SECTION I GENERAL INFORMATION 1 1 DESCRIPTION 1 2 The eight constant voltage constant current power supply models included in this manual use a transistor series regulator combined with triac preregulator for high efficiency excellent regulation and low ripple and noise These supplies are suitably packaged for either bench or relay rack operation The Models 62568 6264B 62678 and 62748 are housed in a 5 1 4 inch high full rack width cabinet and the Models 6263B 62658 6266B and 6271B are housed in a similar 3 1 2 inch high cabinet 1 3 The outputs of these supplies can be varied from zero to full rated voltage or current by setting coarse and fine voltage and current controls on the front panel or they can be programmed remotely by resistance or voltage inputs to rear panel terminals When the voltage controls are used to establish a constant output voltage the current controls establish a current limit that can protect the load from over current when the current controls are used to establish a constant output current the voltage controls establish a voltage limit that can protect the load from excess
134. plies covered by this manual that have equal current capabilities d Auto Series Operation Two or three supplies can be connected in series and have their outputs simultaneously controlled the voltage and current controls or remote programming terminals of one of the supplies designated the master The voltage contributed by each slave is main tained in a constant ratio to that of the master These ratios can be set as desired Auto series operation provides higher output voltages in constant voltage operation and greater voltage compliance in constant current operation Any HP supply that offers auto series operation can serve as a slave supply the master supply does not have to be an auto series model e Auto Tracking Operation Auto tracking is similar to auto series operation except that two or three supplies share a common negative output bus and are interconnected so that the output voltage of each slave supply is maintained at some constant fraction of that of the master supply Ail of the supplies are controlled through the master supply and each supply feeds a separate load 18 SPECIFICATIONS 1 9 Detailed specifications for these power supplies are given in Table 1 1 1 10 OPTIONS 1 11 Options customer requested factory modifica tions of a standard instrument The following options are available for the instruments covered by this manual Where necessary detailed coverage of the options is included throu
135. r and description To order a part not listed in Table 6 3 give a complete description of the part its func tion and its location Table 6 1 Reference Designators miscellaneous electronic part fuse jack jumper A assembly B blower fan capacitor circuit breaker diode device signaling lamp CB CR DS relay inductor meter Table 6 1 Reference Designators Continued plug transistor resistor switch transformer terminal block thermal switch V vacuum tube neon bulb photocell etc VR zener diode X socket 2 integrated cir cuit or network Table 6 2 Description Abbreviations A ampere ac alternating current assy assembly bd board bkt bracket degree Centigrade cd coef coefficient comp composition CRT cathode ray tube CT center tapped dc directcurrent DPDT double pole double throw DPST double pole single throw elect electrolytic encap encapsulated F farad OF degree Farenheit fxd fixed Ge germanium H Henry Hz Hertz integrated circuit ID inside diameter inend incandescent k 10 milli 10 mega 10 m micro 10 met metal mfr manufacturer modular or modified mtg mounting n nano 10 NC normally closed NO normally open NP nickel plated ohm obd order by description
136. r supply has an effect on the accuracy of the programming coefficient For example an internal temperature rise of 15 typical of the temperature difference between no load and full load operation causes the supply output to change by 0 1596 Since the factory calibration procedure for instruments equipped with Option 020 or 040 sets the voltage programming coefficient to within 0 1 the resulting accuracy specification including the effect of the 15 C temperature rise would be 0 25 5 72 Zero Output Voltage Option 020 To calibrate the zero voltage programming accuracy of an instrument equipped with Option 020 proceed as follows a Perform steps a through c of paragraph 5 71 b Adjust potentiometer R124 labeled VOLTAGE ZERO and accessible through hole in rear panel until digital voltmeter reading is Zero volts 1mV 5 73 Zero Output Voltage Option 040 To calibrate the zero voltage programming accuracy of an instrument equipped with Option 040 proceed as follows a Connect supply for remote resistance programming as shown in Figure 3 4 and adjust programming resistor 5 15 for 10 ohms 1 b Connect a digital voltmeter between the S and 5 terminals observing correct poiarity Rotate CURRENT controls fully clockwise and turn on supply d Adjust potentiometer R124 labeled VOLTAGE ZERO and accessible through hole in rear panel until digital voltmeter reads zero volts 1 mV 5 74 CV Prog
137. ramming Accuracy Standard instrument To calibrate the constant voltage programming current of a standard instrument proceed as follows a Connect a 0 1 1 4 watt resistor of the value shown below between terminals S and A2 on the rear barrier strip and disconnect jumper between A1 and A2 6256B 2k 2 62638 62648 4kQ 62658 62668 62678 62718 6274 18k22 b Connect a digital voltmeter between the S and 5 terminals Connect decade resistance in place of R13 d Rotate CURRENT controls fully clockwise and turn on supply e Adjust decade resistance box until digital voltmeter indicates full rated output voltage 0 1 f Replace decade resistance with 5 1 2 watt resistor of appropriate value in R13 position 5 75 CV Programming Accuracy Option 020 To calibrate the constant voltage programming current of an instrument equipped with Option 020 proceed as follows a Perform steps a and b of paragraph 5 74 b Rotate CURRENT controls fully clockwise and turn on supply c Adjust potentiometer R122 labeled VOLTAGE PROG and accessibie through hole in rear panel until digital voltmeter indicates fuil rated output voltage XQ 196 5 76 CV Programming Accuracy Option 040 To calibrate the constant voltage programming current of an instrument equipped with Option 040 proceed as follows a Connect 0 1 1 4 watt resistor of the value shown below between terminals S and 2 on rear barrier stri
138. rcuit protection circuit see Figure 4 1 protects the series regulator in the event the output is shorted while the controls are set to a high output voltage and current The protection circuit monitors the voltage drop across the series regulator If this voltage rises above a preset level the protection circuit limits the current through the series regulator until the preregulator can reduce the voltage across the series regulator Once this voltage returns to normal the short circuit protection circuit is turned off and has no effect on operation of the supply 4 12 The overvoltage protection crowbar monitors the output of the supply and if it exceeds a preset threshold fires an SCR which short circuits the supply The crowbar also sends a turn down signal to the preregulator control circuit 4 13 The turn on control circuit is a long time constant network that gives the supply a gradual turn on characteristic The slow turn on feature protects the preregulator triac and the series regulator from damage that might occur when ac power is first applied to the unit At turn on the control circuit sends inhibiting voltages to the preregulator control and the series regulator via the error and driver amplifiers After a brief delay the inhibiting voltages are removed and the circuit has no further control over the operation of the supply OPEN CIRCUIT CONSTANT VOLTAGE LOAD OPERATING REGION s D CONSTANT CURRENT
139. rent the supply will draw since the onset of constant current operation will cause a drop in output voltage increased ripple and other performance changes not properly ascribed to the constant voltage operation of the supply 5 10 Voltage Output and Voltmeter Accuracy To check that the supply wil furnish its rated output voltage proceed as follows a Connect load resistor R indicated in Figure 5 1 across output terminals of supply b Connect digital voltmeter across 5 and 5 terminals of suppiy observing correct polarity c Turn CURRENT controis fully clockwise d Turn on supply and adjust VOLTAGE controis until front pane meter indicates exactly maximum rated output voltage e Digital voltmeter should indicate 6256B 10 0 2Vde 62638 62648 20 0 4 62658 62668 62678 40 0 8Vdc 62718 6274B 60 21 2 5 11 Load Effect Load Regulation Definition The change jT in the static value of dc output voltage resulting from a change in load resistance from open circuit to a value which yields maximum rated output current or vice versa 5 12 To check the constant voltage load effect proceed as follows a Connect test setup shown in Figure 5 1 b Turn CURRENT controls fully clockwise c Turn on supply and adjust VOLTAGE controls until front panel meter indicates exactly maximum rated output current d Read and record voltage indicated on digital voltmeter e Disconnect load resis
140. rminals on its rear panel The following para graphs first describe normal operation using the normal strapping pattern as it is connected at the factory Later paragraphs cover some optional operating modes including remote voltage sensing remote programming and some methods of operating these power supplies in combinations of two or three 3 5 The DC Power Supply Handbook Application Note 90A is useful source of additional information on using regulated power supplies effectively This 138 page handbook includes chapters on operating principles ac and ioad connections optional operating modes and performance measurements and is available at no charge from your local HP sales office The address of your locai sales office can be found in the back of this manual 3 6 NORMAL OPERATING MODE 3 7 This power supply was shipped with the proper rear pane strapping connections made for constant voltage constant current operation with local sensing and loca programming This strapping pattern is illustrated in Figure 3 2 By means of the front panel voltage and current controls the operator selects either a constant voltage or a constant current output Whether the supply functions in the constant voltage or the constant current mode depends on the settings of the voltage and current controls and on the resistance of the output load For values of load resis tance greater than a critical crossover value equal to the voltage setting divid
141. rmware products which are designated by HP for use with a hardware product and when properly installed on that hardware product are warranted not to fail to execute their programming instructions due to defects in material and workmanship for period of 90 days from date of delivery During the warranty period Hewlett Packard Company will at its option either repair or replace products which prove to be defective HP does not warrant that the operation for the software firmware or hardware shall be uninterrupted or error free For warranty service with the exception of warranty options this product must be returned to a service facility designated by HP Customer shali prepay shipping charges by and shall pay all duty and taxes for products returned to HP for warranty service Except for products returned to Customer from another country HP shall pay for return of products to Customer Warranty services outside the country of initial purchase are included in HP s product price only if Customer pays HP interna tional prices defined as destination local currency price or U S or Geneva Export price If HP is unable within a reasonable time to repair or replace any product to condition as warranted the Customer shall be entitled to a refund of the purchase price upon return of the product to HP gt LIMITATION OF WARRANTY The foregoing warranty shal not apply to defects resulting from improper or inadequate maintena
142. rn on supply and adjust VOLTAGE controls until front panel ammeter indicates either 5 amps or the full load current rating of the supply whichever is less d Close line switch on repetitive load switch setup e Set oscilloscope for internal sync and lock on either the positive or negative load transient spike 5 5 f Set vertical input of oscilloscope for ac coupling so that small dc level changes in power supply output voltage will not cause display to shift g Adjust the vertical centering on the scope so that the tail ends of the no load and full load waveforms are symmetrically displaced about the horizontal centerline of the oscilloscope This centerline now represents the nominal output voltage defined in the specification h Adjust the horizontal positioning control so that the trace starts at a major graticule division This point then represents time zero i Increase the sweep rate so that a single transient spike can be examined in detail j Adjust the sync controls separately for the positive and negative going transients so that not only the recovery waveshape but also as much as possible of the rise time of the transient is displayed t arti i i iui k Starting from the major graticule division representing time zero count to the right 5Ousec and vertically 10mV Recovery should be within these tolerances as illustrated in Figure 5 5 POWER SUPPLY OSCILLOSCOPE THIS DRAWING SHOWS SUGG
143. rument equipped with Option 021 or 040 proceed as follows a Perform steps a through c of paragraph 5 80 b Rotate VOLTAGE controls fully clockwise and turn on supply c Adjust potentiometer R126 labeled CURRENT PROG and accessible through hole in rear panel until digital voltmeter indicates 500 10mv 5 82 Load Transient Recovery Time Adjustment 5 83 To adjust the transient response proceed as follows Connect test setup shown in Figure 5 4 b Repeat steps a through k as outlined in paragraph 5 30 Adjust R30 transient recovery until transient response is within specification as shown in Figure 5 5 5 84 Ripple Balance Adjustment 5 85 This procedure ensures balanced triac operation by ensuring that its conduction time is within 25 of being equal in both directions To check for imbalance proceed as follows a Connect load resistor specified in Figure 5 1 across rear output terminals of supply b Connect variable autotransformer between input power source and power supply input and adjust it for a 115Vac input to the supply c Connect ac coupled oscilloscope across series regulator between 47 and 81 d Turn CURRENT controls fully clockwise turn on supply and adjust VOLTAGE controls for maximum rated output voltage e Adjust oscilloscope to observe 120Hz sawtooth waveform Peak amplitudes of adjacent sawtooth peaks should be within 2596 of each other if amplitude difference
144. s a program ming coefficient of 300 ohms per volt If a greater program ming accuracy is required it can be obtained either by changing resistor R13 as discussed in paragraph 5 74 or if the instrument is equipped with Options 020 or 022 by adjusting potentiometer R122 as discussed in paragraph 5 75 3 38 With the programming terminals shorted terminals A2 to S the no load output voltage of the supply should be 10mV 5 lf minimum output voltage is required that is closer to zero than this it can be obtained either by changing resistor R6 or R8 as discussed in paragraph 5 71 or if the instrument is equipped with Option 020 or 022 by adjusting potentiometer R124 as discussed in paragraph 5 72 CAUTION Do not allow programming terminals A2 and S to become open circuited while resistance programming the output voltage If they do become open circuited the supply s output voltage tends to rise beyond its rated maximum If the supply s current controls and overvoltage crowbar trip point are properly adjusted however no damage to the power supply or load should result 3 39 Constant Voltage Output Voltage Input The rear panel connections shown in Figure 3 5 allow the output voltage to be varied by using an external voltage source to program the supply In this mode the output voltage varies in a 1 to 1 ratio with the programming voltage The load on the programming voltage source is less tha
145. seconds when the rectified ac voltage at the junction of CR36 CR37 and CR38 TP64 forward biases diode CR38 Summing capacitor C15 is then allowed to discharge through CR38 Diodes CR44 and CR43 become reverse biased at RESET FIRING _ THRESHOLD TO A SUMMING POINT j toos 1 3 0 i TP53 TO 5 FIRING PULSE i a 42V D TP67 TO Tl2V TP59 TO TPB i OUTPUT QIB OV 64 67 RESET NOTES ALL WAVEFORMS TAKEN AT MAXIMUM RATED OUTPUT VOLTAGE WITH NO LOAD CONNECTED 2 SCOPE DC COUPLED 3 CLARITY WAVEFORMS ARE NOT DRAWN TO SCALE Figure 4 4 Preregulator Control Circuit Waveforms reset allowing Q19 to turn on Consequently 018 is turned off and capacitor C18 charges up through R71 at a compara tively slow rate until the collector voltage of Q18 reaches approximately 12 4 26 Series Regulator And Driver 4 27 The series reguiator consists of transistor Q6 in the 3 1 2 inch high models or and Q7 connected in parallel in the 5 1 4 inch high models These transistors serve as the series element which provides precise and rapid control of the output The series transistor s are controlled by driver Q3 Diode CR11 is connected across the regulator circuit to protect the series elements from reverse voltages that could develop if one s
146. t pilot lamp 2 lights d Adjust COARSE and FINE VOLTAGE controls 9 for desired indication on voltmeter 2 e Ensure that overvoltage crowbar circuit is operational by slowly turning OVERVOLTAGE ADJUST control counterclockwise with a screwdriver until OVERVOLTAGE lamp lights and voltmeter indication drops to zero volts f Reset crowbar by returning OVERVOLTAGE ADJUST control to its maximum clockwise position and turning off the supply On turning the supply back on the voltage should be the same value as was set in step 9 g To check the constant current circuit first turn off the supply connect a short across the rear panel output terminals see Figure 3 2 and turn it back on NOTE The front pane MONITORING TERMINALS are intended only for monitoring the supply 5 output They cannot be used for measuring the supply s performance specifications These terminals have a 3 amp current limitation h Adjust COARSE and FINE CURRENT controls until ammeter B indicates desired output current or current limit The VOLTAGE controls must be set for a greater than zero output to obtain the output current programmed i Turn off the supply remove the short from its output and read the remainder of these operating instructions before connecting the supply to an actual load 3 3 OPERATING MODES 34 This power supply is designed so that its mode of operation can be selected by making strapping connections between te
147. te 90A which is described in paragraph 3 5 3 35 Connecting a supply for remote voltage or current programming disables the corresponding front panel controls 3 36 The following paragraphs discuss in greater detail the methods of remotely programming the output voltage or current using either a resistance or a voltage input MODELS 62568 62645 62672 62748 Al 2 4 5 AG 5 9 5 214012121010 T 9292 211010109 MODELS 62638 52656 62668 62718 2 4 A5 AG A7 S GNDAB 5 Figure 3 5 Voltage Programming of Output Voltage Unity Gain Whichever method is used the wires connecting the program ming terminals of the supply to the remote programming device must be shielded to reduce noise pickup The outer shield of the cable should not be used as a conductor but should be connected to ground at one end only 3 37 Constant Voltage Output Resistance Input The rear panel connections shown in Figure 3 4 allow the out put voltage to be varied by using an external resistor to program the supply The supply s constant voltage program ming current determines its programming coefficient In the Models 6256B 6263B 6264B 6265B 6266B and 6267B this programming current is factory adjusted to within 1 of 5mA resulting in a programming coefficient of 200 ohms per voit In the Models 6271 and 6274 a programming current of 3 33mA 1 produce
148. th a fixed resistor can have its control restricted to a limited portion of the output range Alternately a switch can be used to select fixed values of programming resistance to obtain a set of discrete voltages or currents The switch must have make MODELS 62565 amp 2645 62678 62745 Al 2 4 5 A6 AT 5 A9 AIO 5 eieigioeieloe e PROGRAMMING RESISTOR AB GND MODELS 62638 62658 62666 627 8 Al 2 A4 5 S 8 45 PROGRAM MING RESISTOR Figure 3 4 Resistance Programming of Output Voltage before break contacts to avoid Producing the output voltage transients that momentarily opening the proaram ming terminals would cause To maintain the temperature and stability specifications of the supply Programming resistors must be stable low noise resistors with a temperature coefficient of less than 30ppm per C and a power rating at least 30 times what they will actual ly dissipate 3 34 Both voltage and current outputs can also be controlled through a voltage input When voltage program ming the output voltage the choice can be made between using a connection that produces a unity gain relationship between input and output or another connection that produces variable voltage gains Only the unity gain connection is included in this manual but methods of voltage programming that provide gains greater or less than unity are discussed in Application No
149. that is amplified and fed back to the series regulator with the correct phase and amplitude to make them equal n this manner the constant voltage comparator holds the output voltage at the level established by the VOLTAGE controls 4 7 During constant current operation the constant current comparator detects any difference between the voltage drop developed by load current flowing through the current sampling resistor and the voltage across the CURRENT controls If the two inputs to the comparator are momentarily unequal an error signal is generated that alters the conduction of the series regulator by the amount necessary to reduce the error voltage at the comparator s input to zero Hence the IR drop across the sampling resistor and fhoratore the Mtt currant curi QOUuO wie Qu tM mir is held at a constant value 4 8 Since the constant voltage comparator causes the output impedance to be low and allows the output current to change whenever the load resistance changes while the constant current comparator causes the output impedance to be high and allows the output voltage to change in response to a load resistance change it is obvious that the two comparison amplifiers cannot control the output simultaneously For any given value of load resis tance the power supply must act either as a constant voltage source or as a constant current source The outputs of both comparators are connected through an OR gate
150. the schematic near current pullout resistors R9 R12 and R13 protects the zener diodes in the reference circuit by providing a path for surge currents that occur during rapid down programming 4 63 Meter Circuit 4 64 The front panel voltmeter and ammeter provide continuous indications of output voltage and current Both meter movements can withstand an overload of 4 7 many times the maximum rated output without damage 4 65 The ammeter together with its series resistors R62 and R63 is connected across current sampling resistor R54 As mentioned previously the voltage drop across R54 varies in proportion to the output current Potentiometer R63 permits calibration of the ammeter 4 66 The voltmeter in series with R44 and R49 and shunted by R56 and R57 is connected directly across the output terminals of the supply Potentiometer R56 permits calibration of the voltmeter 4 67 Additional Protection Features 4 68 The suppiy contains several special purpose com ponents that protect it in the event of unusual circumstances One of these components is diode CR34 Connected across the output terminals of the supply it prevents internal darnage from reverse voltages that might be applied across the supply This could occur for example during Auto Series operation if one supply were turned on or off before the other 4 69 Resistors R58 and R59 limit the output of the supply if the straps between the output buses and the sensin
151. the supply during a portion of its operating cycie If an external source is allowed to pump current into the supply it will cause a 1055 of regulation and might possibly damage the output capacitor To avoid these effects it is necessary to pre load the supply with a dummy load resistor so that it HESS lm POWER SUPPLY WITH NORMAL STRAPPING PATTERN OF FIG 3 2 E CONNECTED 1 ic ____ TAPER RT CHARGING E E F BATTERY inii 1 BATTERY FULL CHARGE VOLTAGE ic CONSTANT CHARGE CURRENT BATTERY VOLTAGE AT WHICH CHARGE RATE WILL BEGIN TO TAPER WITH INSERTION OF RT ecover from the effects of a change in the load resistance Figure 3 14 Battery Charging 3 14 delivers current through the entire operating cycle of the load device 3 79 Battery Charging 3 80 The automatic crossover between constant voltage and constant current exhibited by these supplies makes them ideal for battery charging applications Using this feature a battery may be charged at a constant current unti the maximum charge voltage is reached at which point the supply reverts to constant voltage operation and continues to supply a trickle charge current sufficient to maintain full charge Thus the charging operation can be unattended after properly setting the charging rate and maximum charge voltage and connecting the battery to the output terminals of the
152. this has been done the total voltage of the combination can be controlled by the voltage controls of the master supply or it can be remotely programmed through the master supply 3 55 Setting the Current Controls Auto series opera tion leaves the current controls of all supplies operative but the supply whose current control has the lowest setting determines the point at which automatic crossover to constant current operation begins to lower its output voltage and thus that of the series combination The constant current circuit of a supply has no effect on the outputs of the supplies connected in a more positive position in the series combination but it does affect its own output and the outputs of the supplies connected in a more negative position f the current controls of one of the slave supplies are set the lowest then an overload or short circuit at the output will cause the master supply or the master and the first slave to force current through the reverse volt age protection diodes at the outputs of the downstream slaves Because this current could be excessive either for the diodes or the load the current controls of the slave supplies should be set to maximum and the master supply s current controls used to establish the output current or current limit 3 56 Overvoltage Protection in Auto Series The inter connections shown in Figures 3 10 and 3 11 between transformer 4 in the master and T in the slave s must be m
153. ting limits the maximum output current of the combination Any of the supplies included in this manual can be used as an auto series slave and any well regulated variable output supply can be used as the master 3 51 in applications where coordinated positive and negative voltages are required grounding the center tap of an auto series combination of supplies aliows simultaneous proportional control of both supply voltages 3 52 Determining the Value for Each slave supply has an external resistor Ry associated with it that supplies its voltage programming current If the temperature coefficient and stability specifications of the supplies are to be maintained these must be stable low noise resistors with a temperature coefficient of less than 30ppm per C and a power rating at least 30 times what they will actually dissipate The proper vaiue for Ry when using two units in auto series or for Ry 4 for the first slave when using three units 15 calculated by first finding the voltage pro gramming current of the slave supply This is calculated by referring to Table 1 1 for the remote voltage programming resistance contro coefficient and taking its reciprocal For example the voltage programming current in the Model 62568 is 1 2000 or 5mA Next divide this current into the maximum voltage rating of the master supply to determine Ry for the first slave If our master supply were zero to 25 volt unit for example Rx or
154. tion this power supply has the two primary windings of each of its two input transformers T1 and T2 connected in parallel except for bias transformer T2 in the Model 6274B which has a mary The two windings cf the pre regulator choke A2L1A and A2L1B are also connected in parallel Conversion of the supply to 208 volt or 230 volt operation involves connecting these windings in series replacing the fuses except in the Model 62748 and replacing the pilot light resistor Complete line voltage conversion instructions are given in paragraphs 2 20 and 2 22 single muiti tapped pri 2 19 Converting a 60Hz instrument to 50Hz operation involves replacing several resistors and making some adjust ments Line frequency conversion instructions are given in paragraph 2 25 220 Converting A Standard Instrument To 208 Volt Operation 2 21 To convert a 115 volt instrument to 208 volt operation proceed as follows a Disconnect instrument from power source and remove top and bottom covers and A2 RFI Assembly cover b Replace pilot light resistor RAO mounted on rear of pilot light 051 on front panel with a 120 5 1 2W resistor HP Part No 0686 1245 2 2 c Remove jumpers J1 J2 and J4 from the A2 RF Assembly circuit board and install a jumper in the position marked 13 d Remove the jumpers from power transformer T1 that connect terminals 1 with 3 and 2 with 5 and install a jumper between terminals 2 and 3 See Figure
155. tor f Reading on digital voltmeter should not differ from reading recorded in step d by more than 6256B 1 2mV 6263B 6264B 2 2mV 62658 62668 62678 4 2mV 6271B 62748 6 2mV woe 25 POWER SUPPLY UNDER TEST DIGITAL VOLTMETER Figure 5 1 Constant Voltage Load Regulation Test Setup 5 13 Source Effect Line Regulation Definition The change AEg jT in the static value of dc output voltage resulting from a change in ac input voltage over the specified range from low line to high line or from high line to low line 5 14 To check the source effect proceed as follows a Connect test setup shown in Figure 5 1 b Connect variable autotransformer between input power source and power supply power input Adjust autotransformer for 104 Vac input d Turn CURRENT controls fully clockwise e Turn on supply and adjust VOLTAGE controls until front panel meter indicates exactly maximum rated output voltage f Read and record voltage indicated on digital volt meter Arniwtcvariahle autntranetarmar far 1 9 Adjust variapie autotrai istormer tor 127Vac input h Digital voltmeter reading should not differ from reading recorded in step f by more than 6256B 1 2mV 6263B 6264B 2 2mV 62658 62668 62678 4 2mV 6271B 6274B 6 2mV 5 15 Ripple and Noise Definition The residual ac voltage superimposed on the dc output of a regulated power supply Ripple and noise measurements may b
156. ulator when the unit Is first turned off Feedback network C5 and R30 shapes the high frequency rolloff in the loop gain response in order to stabilize the series regulator feedback loop 4 48 Error amplifiers Q4 and Q12 serve as the pre driver elements for the series regulator 4 49 Overvoltage Protection Crowbar 4 50 The overvoltage protection crowbar circuit protects sensitive loads against the application of an excessively high voltage as might result from a series regulator transistor failure It accomplishes this by immediately shorting the output of the supply as soon as a preset threshold voltage is exceeded Until silicon controlled rectifier CR57 has been triggered it acts as an open circuit and has no effect on the output voltage Transistors 024 and 025 detect overvoltage condition and trigger the SCR to fire When the SCR fires it shorts the supply s output 4 51 During normal operation Q24 is biased on by current through R110 Q25 is kept turned off by 024 and is reverse biased by the voltage divider formed by resistors R106 R108 R109 Zener diode VRS provides a stable reference voltage with which the S potential is compared Potentiometer R109 OVERVOLTAGE ADJUST establishes the output voitage at which CASS becomes forward biased and turns G24 off When G24 turns off Q25 begins to conduct sending a positive going trigger pulse to CR57 and causing it to create a near short circuit across t
157. upply is turned on or off before the other during parallel operation 4 28 Short Circuit Protection 4 29 The short circuit protection circuit protects the series regulator against damage due to a simultaneous full voltage full current condition as might occur if the output were shorted while the controls were set to 44 deliver a high output voltage and current this occurs the preregulator is shut off and Q13 is turned on due to the increased voltage across the series regulator The conduction of Q13 puts R66 in parallel with the current controls to limit the output current to less than 10 of the supply s rating The input capacitor then begins to dis charge through the series regulator and the voltage across the regulator decreases until Q13 turns off The discharge time typically 1 2 to 4 seconds depends on the voltage and current ratings of the supply the size of the main filter capacitor and the control settings Once this recovery time has elapsed the output current returns to the level set by the current controls and the preregulator returns the voltage across the series regulator to the normal 4 voit level 4 30 Constant Voltage Comparator 4 31 constant voltage comparator consists of programming resistors R10 and R11 differential amplitier Z1 and associated components An integrated circuit is used for the differential amplifier to minimize voltage differentials due to mismatched transistors or temperat
158. ure differences 4 32 The constant voltage comparator compares the voltage drop across the VOLTAGE controls with the supply s output voltage 1 a difference exists it produces error voltage proportional to this difference This error signal alters the conduction of the series regulator which changes the output voltage until it is equal to the voltage drop across the VOLTAGE controls Hence through feed back action the difference between the two inputs to 21 is held at zero volts 4 33 One input of the differential amplifier pin 10 is connected to the output voltage sensing terminal of the supply S through impedance equalizing resistor R5 Resistors R6 and R8 zero bias the input 1f the supply is equipped with Option 020 or 040 resistor R123 and potentiometer R124 provide a variable input bias that allows the output voltage to be easily adjusted to exactlv zero volts when the supply is programmed for zero output The other input of the differential amplifier pin 1 is connected to a summing point terminal A2 at the junction of the programming resistors and current pullout resistors R9 R12 and R13 Instantaneous changes in the output voltage or changes in the voltage at the summing point due to changes in the VOLTAGE control setting produce a difference voltage between the two inputs of the differential amplifier This difference voltage is amplified and appears at the output of the differential amplifier pin 12 as an
159. y power input Adjust autotransformer for 104Vac input d Turn VOLTAGE controls fully clockwise e Turn on supply and adjust CURRENT controls until front panei ammeter reads exactiy maximum rated output current f Read and record voltage indicated on digital voltmeter g Adjust autotransformer for 127Vac input h Digital voltmeter reading should not differ from reading recorded in step f by more than 62568 62648 113uV 62638 62678 125uV 62658 62718 184uV 6266 150uV 6274B 116V 5 46 PARD Ripple and Noise Definition The residual ac current superimposed on the dc output of a regulated power supply Ripple and noise measurement may be made at any input ac line voltage combined with any de output voltage and load current within the supply s rating 5 47 Most of the instructions pertaining to the ground ioop and pickup problems associated with constant voltage ripple and noise measurement also apply to the measure ment of constant current ripple and noise Figure 5 8 illustrates the most important precautions to be observed when measuring the ripple and noise of a constant current DIGITAL RESISTOR VOLTMETER CURRENT SAMPLING RESISTOR 0 0252 0 0502 0 0250 0 1672 0 1002 62678 4 02 400w 10 0508 62718 2200 180 10 1679 62748 4 02 300w 10 0558 0 52 200w 2 02 200w 1 09 400w 13 32 120w Figure 5 7 Constant Current Load Regulation Test Setup POWER SUPPLY

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