HP Thermometer 3529A User's Manual
Contents
1. Figure 1 Model 3529A Magnetometer Probe SECTION I GENERAL INFORMATION 1 INTRODUCTION 2 The Model 35294 Magnetometer Probe is an accessory which converts the Model 428A or Model 428B into a magnetometer It is valuable in any Table 1 3529A PROBE application where a magnetic field exists and an accurate determination must be made of either its direction or its magnitude Both accurate and com pact the probe tip is only 1 4 in in diameter it is useful in a wide range of applications such as meas uring the leakage field of transformers etc 3 DESCRIPTION 4 The accuracy of the Model 3529A is better than 3 0 1 milligauss Its bandwidth is from dc non varying fields to 80 cps allowing it to be used in the measurement of ac fields associated with power line frequencies 9 The conversion factor of the Model 3529A is 1 gauss 1 ampere that is the reading from the Model 428A B in amperes is directly equal to the measured field strength in gauss The component of the field sensed is the component which is parallel to the cylindrical axis of the probe allowing the user to eliminate the effects of extraneous fields such as that of the earth approximately 500 milli gauss by orienting the probe Specifications ACCURACY Probe calibrated to specific instrument 3 of full scale from 0 C to 55 C Probe not calibrated to specific instrument 5 of full scale from 0 C to 455 C2. 19 INTRODUCTION 20 INSTRUMENT Maintenance of the Model 428A B milliammeter is the same whether the probe used is the Current Probe Assembly 428A 21A orthe Model 3529A Magnetometer Probe Maintenance of the Model 428A B is discussed in the Model 428A and 428B Operating and Service Manuais Where differ ences between the Current Probe Assembly and the Model 3529A make it necessary to modify the trouble Shooting techniques given in the manual such modif ication is discussed below under troubleshooting 21 PROBE The Model 3529A is a simple device consisting of two drive coils wound around forms containing core material and an output coil wound around both drive coils In general probably the only troubleshooting technique that will be required is the ohmmeter check described in paragraph 27 01364 2 Page 3 22 MECHANICAL ZERO SET 23 When the meter is properly zero set the pointer rests over the zero calibration mark on the meter Scale when the instrument is 1 at normal operating temperature 2 in its normal operating position and 3 turned off Zero set as follows to obtain best accuracy and mechanical stability a Allow instrument to operate for at least 20 minutes this allows meter movement to reachnormal operating temperature b Turn instrument OFF and allow 30 seconds for all capacitors to discharge c Rotate mechanical zero adjustment screw clock wise until meter pointer is to left of zero and
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4. RANGE With 428A 0 3 milligauss to 1 gauss six ranges from 3 milligauss to 1 gauss full scale in 3 10 30 sequence With 428B 0 1 milligauss to 10 gauss nine ranges from 1 milligauss to 10 gauss full scale in 1 3 10 sequence CONVERSION FACTOR OPERATING TEMPERATURE RANGE COMBINED NOISE AND SHORT TERM DRIFT OUTPUT FREQUENCY RANGE MODEL 428B EQUIPPED WITH MODEL 3529A STORAGE RANGE DIMENSIONS 20 C to 55 C Typically less than 0 1 miligauss peak DC to 80 cps 3 db point 40 C to 65 C 1 milligauss milliampere 1 Gauss amp 3 11 16 in by 7 16 in diameter maximum cable 7 feet long 01364 2 3529 901 MAGNETOMETER Page 2 6 CALIBRATION 7 CHECK THE STRENGTH OF THE EARTH S MAGNETIC FIELD AS SOON AS YOU RECEIVE THIS INSTRUMENT USE THIS READING AS A REFER ENCE FOR FUTURE CALIBRATION To measure the earth s field in your locality proceed as follows a The location for taking the reading is important and should be selected with care taking the following into consideration 1 Since the reading is to be the reference for instrument calibration choose a place that will always be accessible 2 Since the presence of strong ac fields will affect the reading choose a location free of power line pickup 3 Since the presence of magnetic materials also wili affect the reading choose a location which either is free of magnetic material suc
5. moving upscale toward zero d Continue to rotate adjustment screw clockwise stop when pointer is right on zero If pointer over shoots zero repeat steps c and d e When pointer is exactiy on zero rotate adjust ment screw approximately 15 degrees counterclock wise This is enough to free adjustment screw from the meter suspension If pointer moves during the Step you must repeat steps c through e 24 TROUBLESHOOTING 25 If you have another Model 3529A Magnetometer Probe or another type of probe such as the 428A 21A Current Probe Assembly or the large aperature Model 3529A probe isolate the trouble to either the instrument proper or to the probe by substitution If the trouble is in the instrument follow the trouble Shooting procedure given in paragraph 29 If the trouble appears to be in the probe see the next paragraph 26 PROBE 27 If the trouble appears to be in the probe discon nect the probe from the Model 428A B and measure the resistance across each of the two windings Only a few ohms should be measured across either winding 1 2 or winding 3 4 terminalnumbers appear adjacent to the pins on the face of the probe connector There shouid be no conductivity between winding 1 2 and winding 3 4 a If an examination of the connector indicates the connector is defective note how the wires are con nected and then replace the connector This con nector is identical to the one used onthe Model 428A B
6. oriented to give a zero reading on the meter When the field to be measured is turned on the probe will indicate the component of the field in the direction of the probe If this is the direction in which it is desired to measure or if merely maximizing the field is desired this procedure is satisfactory However if the field must be measured in some other direction other techniques must be used see following paragraphs 13 The earth s magnetic field can be cancelled out at the point of measurement by building a pair of Helmholtz coils around the probe Orient the coil axis parallel to the earth s field and run current through the Helmholtz coils in the proper direction and magnitude to zero the meter Then insert the field to be measured and measure in the normal way The reading of the meter in this case will be only the desired field 14 If the field to be measured cannot be turned off other techniques must be used If the device generat ing the field can be oriented set the device to a position where you can get maximum reading Record the reading and then rotate the device about an axis on a lne between the object and the probe Rotate for minimum reading on the meter and record this reading The component of the field from the device in the direction of the probe axis is one half of the difference between the maximum and minimum read ings The external field of a magnet may be measured by this method 01364
7. sure to take the measurement at the same location and be sure that there has been no change in the magnetic environment i e no new steel objects etc Any ac fields in the vicinity when making this measurement Should not exceed 0 1 gauss peak Model 3529A SECTION II OPERATION 8 INTRODUCTION 9 The Model 3529A measures the component of the magnetic field which is parallel to the axis of the probe When the meter reads up scale the tip of the probe points toward a north magnetic pole opposite to the direction of the magnetic flux To measure the earth s magnetic field start with the tip of the probe pointed up down in the Southern Hemisphere and toward the south note that the south geographical is a north magnetic pole 10 A true reading of the ambient value ofthe earth s magnetic field will be obtained only when all ferro magnetic materials magnitized or not are kept well away from the probe head If the probe is held by a fixture be sure all of the materials of the fixture are non magnetic and clamp the handle notthe probe tip When measurements must be taken in a building with a Steel framework keep as far away from steel beams and steel reinforced walls or floors as possible 1l MEASURING STEADY MAGNETIC FIELDS 12 The earth s magnetic field is usually a problem when endeavoring to make anaccurate measurement of steady magnetic fields If the field to be measured can be turned off the probe may then be
8. 2 Model 3529A 15 MEASUREMENTS OF ALTERNATING FIELDS 16 Measurements of alternating fields can be per formed only by measuring the output of the front panel OUTPUT jack with an ac voltmeter or an oscilloscope since the meter on the instrument reads only the steady state value of the magnetic field The OUTPUT jack is a de coupled output that gives one volt for a full scale reading of the field as selected by the RANGE switch CAUTION The signal resulting from the steady state value of the magnetic field plus the peak value of the ac field must not overdrive the ampli fliers in the instrument To check the steady field condition observe the meter if the needle is offscale the amplifier may be overdriven To check the ac pick up con nect an oscilloscope to the front panel OUT PUT jack and observe the waveform for clipping 1f either condition is observed the amplifier is saturating and the instrument must be switched to a higher range to give a true reading Because of the magnitude of the earth s field generally ac measurements must be made onthe 1 AMP or greater range SECTION HI PRINCIPLES OF OPERATION 17 DESCRIPTION 18 The Model 35294A is a flux gate type magnetometer which operates in the same manner as the standard probe used with the Model 428A B Refer to Section HI of the Operating and Service Manual for the Model 428A B for a discussion of the flux gate principle SECTION IV MAINTENANCE
9. 4 8A 2 Model 428B par 5 29 5 30 b Adjustments 1 Model 428A table 4 2 steps 9 through 13 2 Model 428B table 5 2 steps 8 throught 12 32 LOOP GAIN CHECK To measure the gain of the amplifier proceed as follows a Model 428B See step 18 table 5 2 Model 3529A 1 Obtain a signal as follows winda5 to 50 turn coil around the magnetometer probe head and couple the coil to an oscillator which furnishes Signals in the 20 eps to 8 cps range such as the Model 200CD Set the audio oscillator for 20 eps 2 Proceed as described in step 18 of table 5 2 except for setting the 0 db point on 20 cps instead of 50 b Model 428A Since the Model 428A does not have an ac output the procedure is somewhat more complieated than that specified for the Model 428B measuring the true gain of the amplifier involves disconnecting the feedback loop Proceed as follows 1 Follow the instructions given in step 14 table 4 2 of the Model 428A manual through zero setting the meter 2 Wind a 5 to 10 turn coil around the magneto meter probe head 3 Feed enough direct current of the proper polarity through the coil togivea 3 ma reading on the Model 428A meter Then turn off this current until step 5 4 Disconnect the jumper across the Test Dis connect terminals on terminal board 428A 75A board nearest front panel this jumper will be found across the terminals nearest the front panel Removing the jumper disconnec
10. b If the wires inside the probe or cable are de fective probably the entire assembiy will have to be repaced as the inside of the probe is filled with Silastic compound to protect the leads from mechanical damage 28 MILLIAMMETER 29 In general instrument troubleshooting and main tenance techniques are the same whether the probe used in the 428A 21A current probe or the Model 3529A magnetometer probe However wherever the Page 4 technique requires current through the probe procedures given in the Model 428A B manuals will require some modification Such modifications are discussed in the following paragraphs 30 CALIBRATION Instead of the accuracy check procedures given in the manuals Model 428A par 4 6A and or step 23 table 4 2 Model 428B par 9 39 and or step 24 table 5 2 check instrument calibration by re measuring the earth s magnetic field strength and comparing the reading obtained with the reference reading made as instructed in paragraph 6 If the readings are not the same follow the adjustment procedure given in the instru ment manual 31 SIGNAL SOURCE Some of the techniques des cribed in the paragraphs listed below require that there be an input signal A suitable ac input may be obtained by placing the magnetometer probe near a power supply transformer With such an input the following procedures can be used a Troubleshooting Waveforms can be used as describe in 1 Model 428A par
11. et 744 223 8103 Scottsdale Ariz 85251 Naely Enterprises 3009 No Scottsdale Rd 802 945 7401 Albuquerque N M 87108 Neely Enterprises 6501 Lomas Bivd N E 505 255 5586 Tucson Ariz 85716 Neely Enterprises 232 So Tucson Blvd 602 623 2564 Las Cruces N M 88001 Neely Enterprises 114 S Water Street 505 526 2486 Rochester N Y 14625 Syracuse N Y 13211 Hewlett Packard Company Pickard Building Molloy Rd and Pickard Dr 315 454 2485 Richmond Va 23230 Bivins amp Caldwell Inc 2112 Spencer Road 703 282 5451 Denver Colo 80222 Lahana amp Company P O Box 22055 Belleview Valley Hy interchange 303 755 1233 Dallas Texas 75209 Hewlett Packard Co P O Box 7166 3405 inwood Road 214 357 188 and 332 6667 4 Poughkeepsie N Y 1268 BOSTON AREA Hewlett Packard Company Yeweil Associates Inc 82 Washington St Middlesex Turnpike 914 454 7330 Burlington Mass 01804 617 272 9000 Middletown Conn 06458 i Yewell Associates inc 589 Saybrook Rd 203 446 6611 New York N Y 10021 RMC Sales Division Hewlett Packard Company 234 East 75th Street 212 879 2023 Englewood N J 07631 RMC Sales Division Hewlett Packard Company 391 Grand Avenue 201 567 3933 ASBURY PARK AREA Robinson Sales Division Hewlett Packard Company Shrewsbury New Jersey 201 747 1060 PHILADELPHIA AREA Robinson Sales Division Hewlett Packa
12. h as steel workbenches and beams or is one in whieh such material will not be added taken away or moved around b Plug Model 3529A into Model 428A B and turn Model 428 ON and allow 15 minutes to warm up c Turn Model 428 OFF for 30 seconds and then mechanicall zero set meter see Section IV for details d Before any measurements are taken the electri cai ZERO adjustment must be centered Turn red ZERO VERNIER control knob fully clockwise and mechanically center the large black ZERO control knob This action will set the instrument zero to within 3 milligauss of zero field As the earth s field is approximately 500 milligauss less than 1 error will be introduced If care is taken when mechanically setting the ZERO control repeatable readings within 0 5 milligauss should be obtained For greater ease in returning to this setting make a mark on the knob and on the panel adjacent to the knob with a lead pencil e Point tip of probe toward the south and up toward the south and down in Southern Hemisphere Extend probe at full cable length from instrument to reduce disturbance from any fields around instrument Carefully orient probe for maximum reading See paragraphs 9 and 10 f Record the value of the maximum reading This is the value to use as a reference for future cal ibration The earth s magnetic field does vary slightly but not enough to be detectable on the 1 AMP range When recalibrating the instrument be
13. ive full details of the difficulty and include the instrument model and serial numbers Service data or shipping instructions will be promptly sent to you There will be no charge for repair of instruments under warranty except transportation charges Estimates of charges for non warranty or other service work will always be supplied if requested before work begins CLAIM FOR DAMAGE IN SHIPMENT Your instrument should be inspected and tested as soon as it is received The instrument is insured for safe delivery If the instrument is damaged in any way or fails to operate properly file a claim with the carrier or if insured separately with the insurance company SHIPPING On receipt of shipping instructions forward the instrument prepaid to the destination indicated You may use the original shipping carton or any strong container Wrap the instrument in heavy paper or a plastic bag and surround it with three or four inches of shock absorbing material to cushion it firmly and prevent movement inside the container GENERAL Your nearest Hewlett Packard field office is ready to assist you in any situation and you are always wel come to get directly in touch with Hewlett Packard service departments CUSTOMER SERVICE OR in Western Europe Hewlett Packard Company Hewlett Packard S A 395 Page Mill Road 54 Route Des Acacias Palo Alto California 94306 Geneva Switzerland U S A Telephone 022 42 81 50 Telephone 415 326 3950 Cable
14. rd Company 144 Elizabeth Street West Conshohocken Pa 19428 215 248 1600 and 828 6200 Baltimore Md 21215 Horman Associates Inc 3006 West Cold Spring Lane 301 664 4400 WASHINGTON D C AREA Hormen Associates inc 94 Rollins Avenue Rockville Md 20852 300 427 7560 Montreal Quebec Hewlett Packard Canada Ltd 8270 Mayrand Street 514 735 2273 Kansas City Mo 64131 Harris Hanson Company 7316 Paseo Street 816 444 9494 St Paul Minn 55114 Crossley Associates Inc 842 Raymond Avenue 612 646 7881 Ottawa Ontario Hewlett Packard Canada Ltd 1762 Carling Avenue 513 722 8142 Toronto Ontario Hewlett Packard Canada Ltd 1415 Lawrence Avenue W 418 249 9196 Chicago iij 60645 Crossley Associates Inc 25001 West Peterson Ave 312 275 1500 St Louis Mo 63144 Harris Hanson Company 2814 South Brentwood Blvd 314 647 4350 High Point N C 27262 Bivins amp Caldwell inc 1923 N Main Street 919 882 5873 Aflente Gc 30305 Bivins amp Caldweil Inc 3110 Maple Drive N E 404 233 ii4I Oriando Fla 32803 Stiles Sales Division Hewlett Packard Company 62 Commonwealth Ave 305 425 554 St Petersburg Fia 33708 Stiles Sales Division Howilett Packard Company 4i0 i50th Ave Madeira Beach 813 391 0211 Huntsville Atc 35801 Bivins amp Caldwell Inc Holiday Office Center Suite No 205 881 4551 Houstos Texas 77027 Hewlet
15. t Packard Co P O Box 22813 4242 Richmond Ave 713 867 2407 A For replacement parts and repair services ja the San Francisco area please contact Hewlett Packard Company 395 Page Mill Road Palo Alto California Tei 415 326 3950 indicates Instrument Repair Stations HEWLETT PACKARD COMPANY 1501 Page Mill Road Palo Alto California 94304 Tel 415 326 7000 TWX 415 492 9200 Cable HEWPACK DYMEC DIVISION 395 Page Mill Road Palo Alto California 94306 Tel 415 326 1755 TWX 415 492 9363 BOONTON RADIO COMPANY Green Pond Road Rockaway New Jersey 07866 Tei 201 627 6400 Cable BOONRACO HARRISON LABORATORIES 41 industrial Road Berkeley Heights N J 07922 Tel 201 464 1234 TWX Summit N J SANBORN COMPANY 175 Wyman St Waltham Mass 02154 Tel 617 894 6300 TWX 617 894 0789 F L MOSELEY CO 409 N Fair Oaks Ave Pasadena Calif 91102 Tel 213 681 0208 TWX PASA CAL 7687 Cable MOCOPAS MARCH 64 003905 WARRANTY All our products are warranted against defects in materials and workmanship for one year from the date of shipment Our obligation is limited to repairing or replacing products except tubes which prove to be defective during the warranty period We are not liable for consequential damages For assistance of any kind including help with instruments under warranty contact your nearest Hewlett Packard field office for instructions G
16. ts the feedback loop 5 Turn instrument on and rezero Turn on Same current as applied in step 3 meter Should now read approximatley 60 to 90 ma If meter reads less amplifier may have deteri orated Proceed as described in step 14 table 4 2 01364 2 HEWLETT PACKARD SALES AND SERVICE OFFICES IN NORTH AMERICA Cleveland Okio 44129 Crossisy Associates inc 5579 Pearl Road 216 884 9209 Hewlett Packard Company 800 Linden Avenue 716 38 4120 Detroit Mich 48235 Crossley Associates lnc 14425 West Eight Mile Road 313 342 5700 PITTSBURGH AREA Crossley Associates inc 2545 Moss Side Blvd Monroeville Pa 15145 412 2705227 Dayton Ohio 45409 Crossley Associates Inc 1250 W Dorothy Lane 513 299 3594 dndicnopolis ind 46205 Crossley Associates inc 3917 Meadows Dr 317 548 4894 Camp Hil Pa Robinson Sales Division Hewlett Packard Company 717 737 6791 Seattle Wash 98109 ARYA lac 1320 Prospect Street 206 622 0177 Salt Loke City Utah 84115 Lahana amp Co 1482 Major St 801 486 8166 Sacramento Calif 95821 Neely Enterprises 2591 Carlsbad Ave 915 482 1463 SAN FRANCISCO AREA VE Neely Enterprises 50i Laure Street San Carlos Calif 94071 415 591 764 LOS ANGELES AREA Neely Enterprises 3939 Lankershim Blvd North Hollywood Calif 94604 213 877 1282 and 766 38li Son Diego Calif 92105 Neely Enterprises 1055 Shafter Stre
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