LAR 500, 630, LAR Magma
Contents
1. 38 REPLACEMENT OF THYRISTORS 39 INSTRUMENTSET DIGITAL 0368 123 884 40 DISPLAY BOARD 2 bvessrkcam ebd A KEA EA NR 40 INDUCTOR SHORT CIRCUITER 0468 122 880 42 INSTRUMENT SET ANALOG 0319 429 882 42 COOLING UNIT E A 43 5 tet acetate teed Sead ah Ted ror mban e a amani ANE a 44 STABILIZER 0468 402001 iie Fiore zc ce Rt ob oir 44 FEED SELECTOR RE 47 INSTRUCTIONS sss va dodo Are 7 49 Technical datac ar eoe dra ael un A Det ea 49 Mains 00 00 kea a EX ee da est UE Rd ua ped vaa ra 50 soot oo KA 51 uu EYE Ge EU RN S P EE WV ET 53 Static characteristi ses Row IER PR ga EC Far 53 Efficiency and power factor 2 54 OL 55 SPARE PARTS b tir a ERE ISERNIA tama 57 Rights reserved to alter specifications without notice cmva2 e1 2 INTRODUCTION Maintenance and repair work should be performed by an experienced person and e2. Edition 020923 ESAB subsidiaries and representative offices Europe AUSTRIA ESAB Ges m b H Vienna Liesing Tel 43 1 888 25 11 Fax 43 1 888 25 11 85 BELGIUM S A ESAB N V Brussels Tel 32 2 745 11 00 Fax 32 2 726 80 05 THE CZECH REPUBLIC ESAB VAMBERK s r o Prague Tel 420 2 819 40 885 Fax 420 2 819 40 120 DENMARK Aktieselskabet ESAB Copenhagen Valby Tel 45 36 30 01 11 Fax 45 36 30 40 03 FINLAND ESAB Oy Helsinki Tel 358 9 547 761 Fax 358 9 547 77 71 FRANCE ESAB France S A Cergy Pontoise Tel 33 1 30 75 55 00 Fax 33 1 30 75 55 24 GERMANY ESAB GmbH Solingen Tel 49 212 298 0 Fax 49 212 298 204 GREAT BRITAIN ESAB Group UK Ltd Waltham Cross Tel 44 1992 76 85 15 Fax 44 1992 71 58 03 ESAB Automation Ltd Andover Tel 44 1264 33 22 33 Fax 44 1264 33 20 74 HUNGARY ESAB Kft Budapest Tel 36 1 20 44 182 Fax 36 1 20 44 186 ITALY ESAB Saldatura S p A Mesero Mi Tel 39 02 97 96 81 Fax 39 02 97 28 91 81 THE NETHERLANDS ESAB Nederland B V Utrecht Tel 31 30 248 59 22 Fax 31 30 248 52 60 NORWAY AS ESAB Larvik Tel 47 33 12 10 00 Fax 47 33 11 52 03 POLAND ESAB Sp z o o Warszaw Tel 48 22 813 99 63 Fax 48 22 813 98 81 PORTUGAL ESAB Lda Lisbon Tel 351 1 837 1527 Fax 351 1 859 1277 SLOVAKIA ESAB Slovakia s r o Bratislava Tel 421 7 44 88 24 26 Fax 421 7 44 88 87 41 SPAIN ESAB I
3. 8 5 3 cmva2se1 LAR 500 630 LAR 500 630 Magma Edition 020923 C component designation in the circuit diagram 500 LAR 500 500M LAR 500 Magma 630 630 630M LAR 630 Magma 0469 255 881 Inductor Complete 0469 255 886 Inductor Complete 0320 620 885 Thyristor bridge Complete 0320 620 886 Thyristor bridge Complete 0320 767 880 Diode bridge Complete 0320 415 880 Diode bridge Complete 0320 028 002 Thyristor 0318 726 001 Thyristor 0490 600 626 Diode 0319 445 001 Thermal cutout 0369 904 001 Thermostat 0467 911 880 Capacitor 0 1 uF 400V 0321 033 880 Diode bridge Complete 0321 468 003 Diode 0320 622 881 Diode bridge Complete 0321 468 003 Diode 0469 170 880 Inductor coil A Only the complete inductor can be replaced in machines older than serial no 305 xxx xxxx 0469 246 880 Inductor coil A Only the complete inductor can be replaced in machines older than serial no 305 xxx xxxx 0469 171 880 Inductor coil B C Only the complete inductor can be replaced in machines older than serial no 305 xxx xxxx 0469 247 880 Inductor coil B C Only the complete inductor can be replaced in machines older than serial no 305 0319 876 880 Circuit board 0319 828001 Control transformer 0365 557 001 Elbow coupling 0490 600 626 Freewheel diode 0368 544 003 Sleeve socket 62 cmva2se1 LAR 500 630 LAR 500 630 Magma 63
4. LAR 500 630 LAR Magma Service manual 0740 800 019 020923 Valid for serial no 024 xxx xxxx to 535 LIST OF CONTENTS Page INTRODUCTION e t LEER US DA MEA DERI EDU LE ERES 3 RATING PLATE e tere umapa ANARA esce E Cw d Satna ns 4 WIRING DIAGRAM LAR 500 630 6 COMPONENT DESCRIPTION WIRING DIAGRAM 8 OUTPUT VOLTAGE FROM THYRISTOR BRIDGE 11 WIRING DIAGRAM LAR 500 630 MAGMA 12 DESCRIPTION OF OPERATION CIRCUIT BOARD 14 CIRCUIT DIAGRAM CIRCUIT 1 18 COMPONENT POSITIONS CIRCUIT BOARD 1 20 TEST POINTS ON CIRCUIT 1 22 TEST PROGRAM FOR CIRCUIT BOARD AP1 24 DESCRIPTION OF OPERATION OF LAR MAGMA IN MMA MODE 27 BLOCK DIAGRAM LAR MAGMA IN 30 DESCRIPTION OF OPERATION CIRCUIT BOARD 31 CIRCUIT DIAGRAM CIRCUIT BOARD 34 COMPONENT POSITIONS CIRCUIT 36 CIRCUIT DIAGRAM CIRCUIT BOARD AP2
5. minal G3 is converted by 1CS to a frequency signal that varies with voltage This digital signal is connected via optocoupler IC6 to the base of transistor Q3 The signal from the collector of O3 is in the form of a 0 to 15 V square wave and is connected to the inverting input of IC3 for filtering inversion and level changing to pro vide a 0 5 V signal to the computer Amplifier offset is adjusted by means of R51 while resistor R55 controls the gain With an input voltage of 0 V on G3 pulse frequency is about 8 kHz and the mark space ratio is about 1746 With an input voltage of 15 V on G3 pulse frequency is about 12 kHz and the mark space ratio is about 25 0 V reference voltage at input G3 produces a welding voltage of 15 V 15 V reference voltage at input G3 produces maximum welding voltage 6 Power supply The power supply board supplies 25 V 15 V 12 V and 5 V 25 V and 15 V are supplied from a 19 0 19 V winding on control transformer 1 the output from which is rectified and smoothed The 25 V supply which is unregu lated powers the thyristor trigger circuits supplying transistors Q4 Q6 via fuse S4 This supply is shown in the diagram as 25 VA The fuse protects the board in the event of an anode gate short circuit in any of the thyristors Another branch of the 25 V circuit 25 VB supplies IC11 The x15 V supply is regulated with fixed voltage regulators and supplies the analogue amplifiers The 9 V AC sup
6. selected by a 3 position switch PAE 2 Remote control for current and voltage PAE 2 is equipped with planetary gearing for accurate setting Available in two designs PAE 2 Box incl 5 m cable PAE 2 Bar incl 5 m cable PAE 4 Programming device for 5 different sets of welding data which are selected via a switch on the front panel Supplied with 5 m of connecting cable Feed Selector Expansion unit for use with double feed units Pulse Aid Pulse unit for aluminium welding 400 500 V with operating level meter 400 500 V without operating level meter 230 V without operating level meter Digital meter set Analogue meter set cmva2ie1 55 Ordering no 0367 317 880 0367 318 880 0367 308 880 0467 277 880 0466 515 882 0368 920 880 0468 040 880 0467 570 880 0467 570 881 0467 570 2 0368 123 4 0319 429 2 cmva2ie1 56 LAR 500 630 LAR 500 630 Magma Edition 020923 Spare parts list cmva2pbg Valid for serial no 024 xxx xxxx to serial no 535 Ordering numbers for LAR 500 630 LAR 500 630 Magma 0467 975 880 0467 975 881 0467 976 880 0467 976 881 LAR 500 LAR 500 Magma LAR 630 LAR 630 Magma Spare parts are to be ordered through the nearest ESAB agency as per the list on the back of the cover Kindly indicate type of unit serial number denominations and ordering numbers according to the spare parts list Maintenance and repair work should be
7. three 35 A Freewheel diode Inductor short circuiting switch option The thyristor short circuits the inductor for about 100 ms when welding starts ensuring a stable start Flat pin outlet 23 pole sleeve socket connection to the wire feeder Current terminal OKC 50 OKC 50 terminal set For connection of the return current cable from the workpiece to the power unit A Low inductance B medium inductance C high inductance 12 pole sleeve socket outlet connector for remote control of welding current in the MMA welding mode Connection block 3 pole Connection block 9 pole Thyristor RFI suppressor 1uF 22 Q Contactor KM1 RFI suppressor 0 5uF 220 Q 10 OUTPUT VOLTAGE FROM THYRISTOR BRIDGE The diagrams below are oscilloscope plots of the voltage across R1 The oscilloscope must be connected to the mains through an isolating transformer AT 3 36ms lt gt ems A 5 No load voltage mean value 47 V DC The no load voltage is about 50 V as a result of the voltage contribution from the base current circuit V4 R4 75 cc TEER ERES KI La 92 4 gt This diagram shows the machine connected to a resistive load and supplying a current of 100 A at a voltage of 19 V with the voltage control knob set to a value of about 4 5 Curve A is the voltage contribution from the thyristor
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9. be disconnected from the board i e the thyristors must not be connected to the board Board contact E can be connected with C1 C2 and C3 by means of a special test cable as shown below which permits the use of the display to see whether trigger pulses are being generated A one in the display indicates that trigger pulses are present while a 0 indicates their absence The left hand indication in the display shows 1 for the first phase E2 for the next and so on No input signals are required for this test CONNECTION C CONNECTION E 1N4007 SWITCH cmva2pbj 26 DESCRIPTION OF OPERATION OF LAR MAGMA IN MMA MODE GENERAL DESCRIPTION The LAR MAGMA is intended for MIG MAG welding MMA welding and air arc gouging The control electronics on circuit board AP3 controls the welding current in the MMA and air arc gouging modes In those modes the current is set by potentiometer RP2 The following description refers to the block diagram on page 30 1 2 3 4 5 10 11 12 cmva2de1 Reference potentiometer RP2 for adjusting the welding current Reference potentiometer connected to remote control socket XS7 for remote adjustment of the welding current Galvanically isolated remote control device The remote control circuit employs a double winding transformer TC2 associated rectifier and voltage stabilisation circuit A D converter optocoupler and D A converter A pulsed voltage transfers the reference vo
10. bridge while curve B is the voltage contribution from the base voltage circuit V3 cmva2de1 11 WIRING DIAGRAM LAR 500 630 MAGMA Terminal XT2 and transformer TC1 are connected for 400 415 V 50 Hz see instruction on page 14 OF I 1 I 5 18 x FEOJ OIO n 0 Leg T 16 XT 1 209 208 0 021 Nose LI Q 0 al 5 gt L i O xx rJ OF 1 e e 1 201121011121 xT2 fej ze gt 09 5 wi jej 2 mk 540 ne _ _ lI ol REAR FRONT i lele PANEL PANEL z B 5 MAGMA 500 630 cmva2de1 12 Connector J is only mounted at circuit board 481 593 884 see description on page 15 item 4 15V ref J1 J2 J3 7 XSI cmva2de1 13 CONNECTION INSTRUCTION 1112101112101112 XT2 Of 510 2 0 XT2 1 11 kj A 230V reo 400 415V 440 460V OHZ 50HZ 60HZ TEI 111210 12101112 XT2 A 500V 550 50HZ 60HZ 02 8921 l 1 1 037 l 18 03 1 TCI cmva1pb9 DESCRIPTION OF OPERATION CIRCUIT BOARD AP1 This description refers to the circuit diagram on page 18 and to the component position diagram on page 20 There are three versions of the circuit board 481 593 880 883 and 88
11. performed by an experienced person and electrical work only by a trained electrician Use only recommended spare parts cmva2se1 57 LAR 500 630 LAR 500 630 Magma Edition 020923 C component designation in the circuit diagram 500 LAR 500 500M LAR 500 Magma 630 630 630M LAR 630 Magma Wiring diagram 0466 780 001 Front panel 0467 120 001 Front panel 0466 781 001 Front panel 0467 121 001 Front panel 0467 003001 Side panel 0467 004 001 Side panel 0467 003 002 Side panel 0467 004 002 Side panel 0467 788 001 Rear panel 0466 899 001 Cover plate 0468 263 001 Platform Replacing 0369 839 001 0468 262 001 Bracket For the platform 0318 170 001 Support 0192 576 004 Indicating lamp 42 48 V white 0192 576 304 Indicating lamp 42 48 V yellow 0318 113 003 Knob 0320 746 001 Mains switch 0366 872 001 Mains switch 0467 176 001 Handle 0159 932 004 Castor wheel 0229 206 401 Wheel washer capsule 0319 362 001 Axle 0215 701 016 Retaining ring 0158 117 880 Cable inlet 0216 610 501 Clamp 0193 189 333 Screw MRX M5x25 0193 586 102 Fuse Miniature circuit breaker 10A FU1 0193 586 101 Miniature circuit breaker 5 A FU2 FU3 0160 362 881 Welding current terminal OKC XS2 XS5 0481 195 882 Circuit board AP2 0368 544 005 Sleeve socket XS1 0193 513 105 Contact sleeve 0321 173 001 Chain 0320 781 001 Escutcheon plate 046
12. ristor V7 the short circuiting switch when the voltage across the inductor drops R82 and C51 form a filter circuit that protects against unintentional triggering of the op tocoupler thyristor C26 is a decoupling capacitor 9 Thyristor trigger circuits The thyristor trigger circuits consist of operational amplifier IC11 the non inverting input of which is connected to 1 4 V supply obtained from the 5 V supply and poten tial divider circuit R76 and R77 The inverting inputs of the amplifiers are connected to the computer Power supplies to the amplifiers are 25 V and 5 V with the latter being obtained by a zener diode in series with the 15 V supply When the inputs to the amplifiers are low the outputs are high Transistor Q4 Q5 Q6 conducts and provides a trigger pulse to the thyristor s The voltage level of the trigger pulses is about 0 6 V if the thyristors are connected to the circuit board If the thyristors are disconnected from the board the voltage level of the pulses is about 22 V Current is limited by resistor R68 R71 R74 Resistor R69 R72 R75 prevents leakage currents or interference from triggering the thyristor s Resistor R100 pulls down the non inverting inputs of the amplifiers to 0 3 V in the event of loss of the 5 V supply blocking the output of trigger pulses 10 Control circuits The control circuits deal with synchronising the signals to the mains calculating the necessary firing angles c
13. the no load voltage is about 17 V when is at its minimum position and about 48 V with RP1 at its maximum position Conductor 070 must be disconnected and reconnected only when the machine is disconnected from its mains power supply COMPONENT DESCRIPTION WIRING DIAGRAM The following descriptions refer to the components shown in wiring diagram LAR 500 630 on page 6 and wiring diagram LAR 500 630 MAGMA on page 12 Components only mounted in the Magma machines are marked with an m to the left of the description AP1 Circuit board power unit DESCRIPTION OF OPERATING CIRCUIT BOARD on page 14 AP2 Interference suppressor circuit board see circuit diagram on page 38 m 3 Circuit board controlling the main thyristors during MMA welding and air arc gouging DESCRIPTION OF OPERATING CIRCUIT BOARD AP on page 31 C1 Start and run capacitor for cooling fan EV1 3uF 400 V C2 Capacitor 1uF 400 V C3 C4 Capacitor 0 1uF 400 V C5 Capacitor 4uF 250 V for reducing the speed of fan motor M1 FU1 Miniature circuit breaker 10 A anti surge Protects the 42 V supply from transformer FU2 Miniature circuit breakers 5 A Protect the 230 V supply from the primary FU3 side of TC1 to terminal XT3 external cooling water pump HL1 Indicating lamp 42 48V white Indicates that the main power supply switch is On HL2 Indicating lamp 42 48V yellow Indicates excess temperature in the power unit See also ST1 a
14. will be energised The fan will start the relay will close and indicator lamp 2 will light The welding current is continuously variable 4 Connect the gouge to and the return cable to A Fit a carbon rod to the gouge You can now start gouging cmva2ie1 52 Maintenance Once a year blow the power source clean using dry compressed air at reduced pressure The power source should be cleaned more frequently if used in a very dusty or dirty environment Static characteristic u LAR 500 u M LAR 630 100 200 300 400 500 600 700 800 lo A Primary 3 50 Hz 400 V U2 M MAGMA 500 ga LER LII EP i a Position MIG MAG MAX resp MIN Einstellung MMA MAX bzw MIN Standardized load voltage acording to 974 cmva2ie1 53 Efficiency and power factor U n Inductance Inductance A Standardized load voltage acc to VDE 0542 and NF A85 013 Primary 3 50 Hz 400 V U n MAGMA 630 Standardized load voltage acording to IEC 974 cmva2ie1 54 Extra accessories For remote control of welding parameters PHB 1 fitted with planetary geared multi turn potentiometer for exact adjustment PHB 2 fitted with coarse and fine adjustment potentiometers PAB 6 Three arbitrary current and voltage combinations can be preset and
15. 1 A 55 1 1 1 1 i i i 1 i i 1 i 1 1 i ie i MIGJMAG arc air gouging 1 4 gt 224 206 gt to B10 max mim QU KEKR from TC1 205 gt to 2 remote ref 2 223 cmva2e05 cmva2de1 34 k q E oo Approximately values when the thyristor is disconnected from AP3 DUE md Y L3 ue L 43 49 yellow u wi MER 02 1 red 4 46 XS6 API _ X811 L2 k 1 E2 07 1 1 2 J 3 yellow R59 4 SaR 1 peg mio ov 5 red Y Ka API lt 10V Y TO LI 5 1 45V El 1 H Dr yellow vi 1 1 i 048 C49 c50 C60 R126 2 zus 19V AC C51 2 8 C83 ha gsm B12 Bil B10 B5 i B9 AT 12 11 19 22 5 i not 01 used M QF 4 6 18 17 not used i 200 201 205 206 207 i MIG MAG 38 V AC from TC1 i I 1 i MMAJ i OV from 422 i arc air gauging cmva2e06 cmva2de1 35 COMPONENT POSITIONS CIRCUIT BOARD
16. 4 The difference between the versions is described under item 4 on page 15 1 Mains synchronising The synchronising winding on transformer TM1 provides inputs 1 A2 and with a phase voltage signal of 18 5 V 0 4 V at nominal mains voltage Three zero crossing detectors provide the necessary reference signals for controlling the thyristor firing angles The incoming phase signal at terminal A3 is filtered by RC net work R1 R2 and C10 which produces a phase shift of 30 The signal is then fed to the non inverting input of comparator IC1 The comparator provides a square wave sig nal of 0 5 V to the control circuit 10 2 Analogue inputs The analogue inputs are used to measure voltage signals from the shunt representing the welding current thyristor bridge output voltage and arc voltage At a welding current of 600 A the shunt produces an output voltage of 60 mV which is amplified by operational amplifier IC2 This amplified voltage signal is used for current control It is also used to provide a signal to the power unit s digital ammeter and the overcurrent protection circuitry Overcurrent protection is set at 750 A cmva2de1 14 The circuits for measuring the thyristor bridge output voltage and the arc voltage are identical apart from the output filters As the neutral of the electronic circuitry is connected to the positive side of the welding current circuit incoming voltages are negative which means that
17. 7 018 001 Knob With planetary gear 0191 870 512 Potentiometer RP1 RP2 0147 866 001 Toggle switch SA1 SA2 58 cmva2se1 LAR 500 630 LAR 500 630 Magma Edition 020923 UNO An 15 cmva2pb4 59 cmva2se1 LAR 500 630 LAR 500 630 Magma Edition 020923 C component designation in the circuit diagram 500 LAR 500 500M LAR 500 Magma 630 630 630M LAR 630 Magma 28 1 1 1 1 0369 827 001 Fan M1 0467 970 880 Transformer Complete 0467 970881 Transformer Complete 0467 968 880 Transformer coil 0467 969 880 Transformer coil 0321 003 880 Resistor 0467 992 881 Shunt 0467 119 880 Shunt 0193 045 002 Terminal block 0162 772 001 Terminal block 0320 378 008 Terminal block 0162 781 901 Load relieving clamp 0467 973 001 Control transformer 0193 296 101 Contactor 0191 085 203 Capacitor 0193 503 101 Contactor 42 0041 051 601 Filter 0 5 uF 220 Q 0191 603 204 Capacitor 0046 006 704 Capacitor 1 uF 400V 0192 579 226 Resistor 100 Q 50 W 0466884003 Terminal block 3 pole 0467 169 002 Resistor 0 7 Q 0468 122880 Inductor short circuiter 0320 028 002 Thyristor 0467 910880 Cable set 0467 910881 Cable set 0467 911 881 Capacitor 0 1 uF 400 V 0481 593 884 Circuit board 60 cmva2se1 SSIDHY cmva2pb5 Edition 020923 1 5 L SSS 5 5 5 8 5 3
18. AP3 cmva2eba 36 cmva2de1 123 2 19 gt R118 pg Q17 Se 4 Q20 26 ERS Oe E cun cmva2ebb 37 cmva2de1 CIRCUIT DIAGRAM CIRCUIT BOARD AP2 cmva2pbb cmva2de1 98 REPLACEMENT OF THYRISTORS When fitting replacement thyristors it is extremely important that they are correctly secured i e with a clamping force of 4500 450 kp 10 Clean the flat surfaces of the thyristors and heat sinks carefully and remove any burrs or traces of grease or oil Apply a very thin film of silicone grease to the contact surfaces of the heat sink and position the thyristor between the surfaces with the symbol on the thyristor facing in the direction as shown in the diagram below Centre the thyristor by locating the pin projecting from the pressure cap in the depression in the thyristor body Start by finger tightening the nuts enough to remove play between the nuts and washers Then using a dial gauge or depth gauge measure the distance from the plate to the spring as shown in the diagram below Tighten the nuts alternately with a spanner until the distance has decreased by 0 9 0 05mm FITTING OF THYRISTORS Control electrode Cathode side Positive out lt Anode side Conducting direction cmja2p02 cmva2de1 39 cmva6e09 o Lut JN REEL UE SUOI1ISOd 1u uoduioo AV IdSIG sonne quio
19. MA welding mode Elevated starting current starting boost hot start The starting current circuit briefly increases the welding current when starting to weld The peak value of the starting pulse is about twice the set value of welding current and gives the power source good starting characteristics during MMA welding Power supply unit for the electronic equipment supplying stabilised DC at 15 V The neutral of the electronic circuitry is connected to the positive of the welding voltage on XS2 The power supply unit receives an alternating voltage from 1 Control comparator amplifier which compares the voltage signals from 8 12 and then amplifies the summing voltage to provide a suitable control voltage signal to the trigger unit 17 The good dynamic welding performance of the LAR MAGMA is partly due to the characteristics of the amplifier The no load detector 21 reduces the amplifier output signal when there is no arc Trigger unit The trigger unit consists of three identical circuits one for each phase Each circuit provides trigger pulses for its thyristors with phase angles in proportion to the output voltage from the control amplifier Auxiliary windings on the main transformer provide synchronising signals The switch QF1 disconnects the trigger pulses from AP3 when LAR MAGMA is in MIG MAG welding mode Shunt amplifier amplifying the signal from the current shunt to a suitable level for input to 12 Short ci
20. NTROLLER 52 53 54 55 SLOW B 5 POWE R S UPPLY cmva2de1 19 cmva2e02 COMPONENT POSITIONS CIRCUIT BOARD AP1 481593 880 E C ORE D 0 3158 SLOW lt P2 51 cmva6eb7 20 cmva2de1 kant 7 j O b BY oli s if OLO doms 6 O 5 cmva6eb8 21 cmva2de1 TEST POINTS ON CIRCUIT BOARD AP1 Unless otherwise stated the reference point for all voltages is the electronic neutral When measuring voltages on the board we suggest that the instrument neutral be connected to the negative terminal of electrolytic capacitor C60 or to the positive welding terminal For identification of the test points listed below refer to the component position diagram on page 20 and to the circuit diagram on page 18 The test points are marked with MP in the diagram Test point 0 Electronic neutral 1 5 V power supply tolerance 0 02 V 2 15 V power supply tolerance 0 6 V 3 15 V power supply tolerance 0 6 V 4 Welding voltage reference to the computer At 0 V min ref at terminal G3 the value at MP4 should be 0 0 V 0 02 V while with a value of 15 V at terminal G3 the value at MP4 should be 5 0 V 0 02 V 9 Start and stop sensing During the Stop state the voltage is 5 V while at Start with 42 V AC across B1 B2 MP9 go
21. TC1 are connected for 400 415 V 50 Hz see connection instruction CONNECTION INSTRUCTIONS 12101112101112 XT2 4 11 Lj 230V 220 230V SOHZ 60HZ 0 0 1 I 029 591 I o3 8 7 TCI 01112101112101112 xT2 L A 400 415 440 460V SOHZ 60HZ 02 037 o3 18 O3 03 REAR FRONT PANEL PANEL cmva2de1 6 Connector J is only mounted at circuit board 481 593 884 see description on page 15 item 4 KG Ene N J 15 ret 414243 5 XSI ST1 514 esi y pU cmva2de1 7 GENERAL DESCRIPTION LAR 500 630 The LAR 500 630 are thyristor controlled power units for MIG MAG welding The main circuit consists of three thyristors and three diodes connected to form a full wave bridge Voltage ripple particularly at low welding voltages is reduced by applying a base voltage of 15 V via diodes V3 supplied from a separate winding for this purpose on the main transformer Similarly a base current is arranged by rectifying the output from the main transformer secondary winding via diodes V4 and connecting it to the positive welding terminal through a 1 1 Q resistor Note that the no load voltage of the machine is about 50 V as a result of the voltage contribution from the base current winding In order to be able to measure the true no load voltage it is necessary to disconnect conductor 070 from the base current winding With the base current winding disconnected
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23. bility i e when Feed Selector Puls Aid or counter balance are used Fitting is carried out according to the enclosed fitting instructions cmva2ie1 51 Operation Semi automatic welding Use the recommended shielding gas Set the switch 1 to the semi automatic welding position 5 The fan will start and the indicator lamp 2 will light Press the trigger on the welding gun The power source relay will close at the same time as the wire feed unit starts and the gas valve opens The gas flow can be adjusted recommended rate 10 18 l min depending on application When adjusting the gas flow you should release the feed roller pressure arm to prevent wire being fed through unnecessarily Set the required welding voltage using the potentiometer 3 on the front panel of the power source and set the required wire feed speed using the potentiometer on the front of the wire feed unit ba12d001 LAR 500 630 Magma Manual welding MMA 1 Set the switch 1 to the manual welding position 6 The control transformer will be energised The fan will start and the indicator lamp 2 will light The welding current is continuously variable 4 Connect the welding cable to or C depending on the type of electrode and the return cable to C or Insert and electrode in the electrode holder You can now start welding Arc air gouging L Set the switch 1 to the arc air gouging position 7 The control transformer
24. eference The secondary output voltage from transformer TC1 supplies 38 V to control power supply transformer TC2 The secondary voltage from TC2 supplies 19 V to remote control output voltage regulator VR1 via terminals B6 and B7 and diode bridge 1 The output voltage from VRI is 16 2 V which is reduced to 15 6 V after diode D12 The regulator is current limited to 120 mA by resistors R104 107 transistor O19 and diode D12 making the remote control connection short circuit proof 5 The D A converter which recreates the mean value of the reference signal from the pulse train from 3 The input signal is first amplified and filtered trimming potentiometer R87 adjusts the output signal from IC4 1 to 0 V when the remote control potentiometer is at its minimum position and to 11 5 V when the potentiometer is at its maximum position The signal is then passed to analog switch IC1 which is controlled by the LOCAL REMOTE selector switch cmva2de1 31 6 LOCAL REMOTE selector switch Three analog switches IC1 control signal switching for selection of local internal or remote external control of the welding current These switches are in turn controlled by selector switch SA2 The control voltage which can be measured at terminal A3 is either 0 V SA2 closed internal reference or about 27 V SA2 open remote reference IC1 contains four identical analog switches of which three are used for local remote changeover switching The s
25. es low 0 V 10 Arc voltage signal 0 5 V linearly proportional to the input voltage at I2 For an input voltage of 64 V on 12 MP10 must have a value of 5 0 V 11 Thyristor output voltage 0 5 V linearly proportional to the input voltage at I1 For an input voltage of 64 V on I1 the voltage at MP11 must be 5 0 V 12 Shunt voltage signal 0 5 V linearly proportional to the input voltage between B3 and B4 With an input voltage of 0 1024 V between B3 and B4 the voltage at MP12 must be 5 0 V 13 15 Synchronising signal 0 5 V pulses Incoming 50 60 Hz synchronising voltage on 1 A2 and produces 50 60 Hz square wave at MP13 15 16 Enable signal for the computer 0 or 5 V Must be High for the computer to work 17 19 Ignition pulse outputs The following conditions must be fulfilled if ignition pulses are to be obtained when starting to weld e Alternating synchronising signals on A1 2 and Welding torch contact closed i e MP9 is Low e voltage between 5 V and 64 V present on I2 Ignition pulse length about 200 us Peak value of pulse voltage without thyristor load is about 22 V 20 Reference level for ignition circuits is 1 4 V cmva2de1 22 21 cmva2de1 Control signal for the inductor short circuiter This signal is activated while welding is not in progress and does not turn off until 100 ms after the start of welding i e 100 ms after receipt of the following signals Alternating synchronising s
26. formation for correct firing The voltage between B13 B14 B15 is approximately 35 V The ignition pulses are connected to each thyristor The gate connections are twisted together with the associated neutral connections in order to minimise the risk of interference in the gate circuit cmva2de1 32 18 The switch QF1 interrupts the power supply to output transistors Q9 Q12 and O15 in the trigger unit when LAR MAGMA is in the MIG MAG welding mode 19 The shunt amplifier amplifies the voltage signal from the shunt Trimming potentiometer R132 adjusts the output voltage from the amplifier to 20 mV when no welding current is flowing The shunt provides an output voltage signal of 120 mV for 600 A welding current 22 This part of AP3 is not used in LAR MAGMA 24 Air arc gouging MMA changeover A contact on switch QF1 links contacts A9 A12 in the galvanically isolated remote control circuit to change the operating mode to air arc gouging Switch OF1 also selects MMA or MIG MAG welding modes Optocoupler IC11 is activated in the air arc gouging mode and in turn activates the air arc gouging control circuits cmva2de1 33 CIRCUIT DIAGRAM CIRCUIT BOARD AP3 30V A 15V remote 27V Lo Iams internal ov i i v es not used 199 01 Arc voltage 204 hs I 203 3 4 83 Shunt voltage 9 to 120mV 202 1 1 i 1 1
27. ifier 2 Indicates the voltage current characteristic for MIG MAG welding 3 Indicates the voltage current characteristic for MMA welding 4 Indicates that the unit is intended for connection to a three phase 50 60 Hz supply cmva2de1 5 The machine s serial number consisting of three groups of figures The first group xxx indicates the version The numerals indicate the year and week of approval of the design version The second group yyy indicates the year and week of the machine s final testing e g 305 indicates 1993 week 5 The final zzz group consists of three or four numerals and is a consecutive serial number from 0001 to 9999 6 Shows that ESAB complies with the international IEC 974 1 standard 7 X Theintermittence factor i e the length of time for which welding can be performed at the specified welding data expressed as a percentage of a ten minute period l Current at the respective intermittence factor U2 Voltage in accordance with the arc voltage characteristic Open circuit voltage 8 U and l indicates supply voltage and primary current at the indicated duty factors AF indicates that the unit is fan cooled IP23 indicates the enclosure class with respect to protection against entry of foreign bodies and or water Slrhis symbol indicates that the unit is designed for use in areas of elevated electrical hazard cmva2de1 5 WIRING DIAGRAM LAR 500 630 Terminal XT2 and transformer
28. ignals on Al A2 and Welding torch contact closed i e MP9 is low voltage of at least 2 mV representing a welding current of at least 20 present on terminals BA B3 Operation of the inductor short circuiter can most easily be checked by connecting an oscilloscope across resistor R3 which is connected in parallel with the inductor Note that the oscilloscope must be powered from a galvanically isolated power supply 23 TEST PROGRAM FOR CIRCUIT BOARD AP1 The control board for the LAR 500 630 incorporates a built in test routine with its output data except for that for test no 13 being displayed by the display unit The upper line of the display indicates the number of the test while the lower line indicates the result or value of the test Enter the test mode by short circuiting contacts C1 and C4 on the board when powering up the board Step through the tests progressively by opening and closing the link between C1 and C4 We recommend the use of a special test cable as shown in the diagram on page 26 Testing can be performed with the board mounted in the unit but not when welding is in progress When performing test no 14 contact E for the ignition pulses must be disconnected before testing When in the Torch Contact Closed test position make sure that the pressure arm in the wire feed unit is slackened in order to avoid unintentional feed of the wire In order to avoid problems always di
29. in the description of the circuit board 1 Reference input Reference potentiometer RP2 2 5 10 2 W linear is supplied at 15 V and connected to A2 A4 and A5 The reference voltage is limited to 0 10 V by potential divider R3 R4 and connected to analog switch ICT 2 Remote control device The remote control device which can be a potentiometer or a pulse generator is connected to circuit board terminals A10 A11 and A12 via remote control input XS7 It is supplied at 15 V via pins F and H in input XS7 The reference voltage from the remote control device is connected to pin G 0 V between G and H results in minimum current and 15 V gives maximum current 3 A D converter The A D converter and the voltage reference unit see 4 below are galvanically isolated from the rest of the control circuitry by optocoupler IC12 see 5 below The A D converter converts the reference signal to a pulse train in which the mark space ratio represents the magnitude of the reference signal Optocoupler IC12 transfers the pulse train to the D A converter thus ensuring complete galvanic isolation between the voltage signal from the remote control input and the other electronic equipment If selector switch SA2 is in the REMOTE position but no remote control device is connected the power source will give low welding current as R112 in the A D converter produces a low value of current reference signal 4 Galvanically isolated voltage r
30. ircuit board 883 and 884 program version P1 02 is mounted those boards are replacing 880 The difference is that program P1 02 senses if there is a jumper between input C2 and C4 or not Program version P1 02 is mounted from serial no 305 xxx xxxx Version 884 has a connection denominated J J2 and J3 are connected in paralell with C2 and C4 Version 884 fits in all LAR ma chines version 883 can not be mounted in the Magma machines When the jumper between J3 C2 and J2 C4 is mounted the arc voltage control is dis abled the ignition angle of the thyristors is locked This improves the welding perform ance when using basic flux cored wire All new circuit boards are delivered with the jumper mounted not connected 4 TEST INPUT AND METHOD SELECT LAR Magma 4 cmva2e08 Test input and method select LAR Magma circuit board version 884 cmva2de1 15 5 Galvanically insulated voltage reference This circuit provides a galvanically insulated voltage reference to the computer It is sup plied from a separate winding on control transformer TC1 Voltage regulator pro vides a regulated 15 V supply while transistor Q8 and resistor R99 form a current limit circuit set at 100 mA Fuse 51 is rated at 315 mA The regulated 15 V signal is applied to the welding voltage control potentiometer via ter minals G1 and G2 The 0 15 V voltage signal returned from the potentiometer via ter
31. lectrical work only by a trained electrician Use only recommended replacement parts This service manual is intended for use by technicians with electrical electronic training for help in connection with fault tracing and repair This manual contains details of all design changes that have been made up to and including August 2002 The LAR 500 630 and LAR 500 630 Magma are designed and tested in accordance with international and European standard IEC EN 60974 1 and EN 50199 On completion of service or repair work it is the responsibility of the person s etc performing the work to ensure that the product does not depart from the requirements of the above standard cmva2de1 3 RATING PLATE The rating plate is secured to the rear of the machine The following points describe what the various items on it mean ESAB AB Box 106 5 6950 Sweden ade in Sweden LAR 630 MAGMA xxx xxx xxx 5 1 IEC 974 1 6 75A 18V 630A at 44V 2 1 3 U 4 8 Ui 420 1 54 Al48 Al43 550 F Cooling IP 23 i cmva2p01 LAN 630 is the type designation for the Welding machine The first letter L indicates that LAR is a rectifier while A indicates that the power unit is designed for semi automatic welding and R indicates the design generation The numerals 630 indicate the maximum welding current 1 These symbols indicate that the LAR 630 comprises a transformer and a rect
32. ltage from the remote control terminal socket via the optocoupler to the D A converter the output of which is an analog reference voltage Selector switch SA2 selects local or remote control of the reference voltage The actual switching of the voltage reference signals is effected by analog switches the block diagram shows the switching only schematically Current reference boost in response to short circuits Reference voltage input from the local and external potentiometers respectively This circuit boosts the welding current in the event of an arc short circuit thus preventing the electrode from burning on to the work during welding The current reference signal is increased electronically via 7 and 20 Assists striking of the arc by means of an elevated current reference signal during starting See 14 Hot start Reduces the welding current in the event of a long duration short circuit i e if the electrode has burnt on to the workpiece See 13 Foldback Input for current signal from elevated shunt voltage 27 13 14 15 16 17 18 19 20 21 cmva2de1 Foldback This is a timer circuit that starts when the arc is short circuited It reduces the welding current via 11 if the short circuit persists i e if the electrode has burnt on to the workpiece This helps to protect the thyristors against abnormally high and or long duration short circuits The foldback feature operates only in the M
33. nd ST4 KM1 Main contactor 42 V 50 Hz Controlled by the welding torch contact In LAR Magma KM1 is also energized when the MMA or arc air gouging mode is activated KM2 Contactor 42 V 50 Hz Controlled by thermostat ST2 and ST3 Short circuits capacitor C5 allowing fan motor M1 to run at full speed cmva2de1 8 L1 M1 PA1 PV1 QF1 m QF1 R1 R2 R3 R4 RP1 m RP2 RS1 m RS1 SA1 m SA2 ST1 ST2 ST3 cmva2de1 Inductor connected in series with the welding current circuit The purpose of the inductor is to limit the short circuit current and reduce welding harshness From serial no 305 xxx xxxx the inductor has a new design 30 50 of the inductor winding is connected to welding terminal A 73 75 to terminal B and 100 to terminal C The values in brackets are referring to older machines For older machines the new inductor can be used as a spare part see the spare parts list Cooling fan motor connected for two speed operation see ST2 Ampere meter analog option Voltmeter analog option Main On Off switch In the On position 1 the unit is energised the cooling fan starts and indicating lamp HL 1 lights The LAR Magma allows change over between semi automatic manual welding and arc air gouging by turning switch QF1 Resistor 100 2 50 W Together with resistor R2 it provides a dummy load for the thyristors to enable them to fire properly when operating on no load Resis
34. nted in the main transformer It works in paralell with thermal switch ST2 The switch is mounted from serial no 338 xxx xxxx STA TC1 m TC2 TM1 V1 V2 V3 V4 m V5 V7 XP1 XP2 XS1 XS2 XS3 XS5 m XS7 XT1 XT3 XT5 XT2 Z1 2 cmva2de1 Thermal cutout mounted on the inductor L1 It works in series with thermal cutout ST1 The cutout is mounted from serial no 535 xxx xxxx Control power transformer An autotransformer winding on the primary side supplies 230 V to the fan motor The secondary voltages are 42 V between 11 and 12 2 x 19 V between 21 22 23 9 V between 25 and 26 15 V between 27 and 28 Control power transformer for circuit board AP3 Supplied at 38 V AC from connection 21 and 23 on TC1 The secondary voltage is 18 V AC Main transformer having three secondary windings The main winding supplies current to the thyristor rectifiers The base voltage winding supplies current to diodes The purpose of the base voltage is to even out the voltage peaks at low welding currents e The synchronising winding supplying a synchronising signal for con trolling the thyristors firing points to circuit board AP1 and AP3 in LAR Magma The winding voltage as measured between terminals 1 2 A1 A3 and A2 A3 on circuit board is 18 5 V 0 4 V at nominal mains voltage Thyristors three Diodes three in LAR 500 and six in LAR 630 Base voltage diodes 18 Base current diodes
35. ontrolling the trigger circuits and maintaining constant welding voltage In addition they provide overload protection output of data to the display unit and control of the inductor short circuiter 11 Reset circuit The reset circuit prevents incorrect operation of the computer in the event of loss of power supply It monitors the power supply to the computer and generates a reset signal if the voltage drops When the power supply is restored the control program starts again from the beginning cmva2de1 17 CIRCUIT DIAGRAM CIRCUIT BOARD AP1 Rectifier bridge 2 CONTROL CIRCUIT Shunt voltage RSI 600 G mV IC Rectifier bridge 1 IC8 Arc voltage from X53 2 2 0 54V ICIO Torch switch B01 B1 42 V AC when 1 is activated from the wire feeder B02 B2 14 TEST INPUT AND mr MO METHOD SELECT LAR L Magma 1 1 1 1 IC5 ex 14 pu 2 gt x C44 1 ICI 6 Ho ov Bl lat Fe ix 1 1 gt i v i 5 GALVANIC ISOLATED S ay VOLTAGE REFERENCE cp NE J C5 Ja CE 005 Mot connected U ref cmva2e01 cmva2de1 18 224 200 pS approximately values when the thyristor is disconnected from AP1 8 INDUCTOR SHORTCIRCUITING CO
36. ower transformer are arranged for the appropriate supply voltage and that the correct fuses are fitted See the connection instructions on page 50 The recommended fuse ratings are in accordance with Swedish standard requirements If requirements differ in other countries the appropriate fuses should be fitted 3 Connect the unit to a three phase power supply Connect an earth lead in accordance with applicable standards to the earthing bolt marked on the plate in front of the mains ter minal 4 Connect the control cable from the welding power source to the wire feed unit Connect the welding current cable from the wire feed unit to the terminal marked Connect the return current cable from the workpiece to one of the terminals marked Note that reversed polarity connections may be called for depending on the type of weld ing electrode used Terminal A is used for short arc welding thin materials or bottom runs and for aluminium Terminal B is used for short arc welding but gives a somewhat hotter weld than terminal A Terminal C is used for spray arc welding of thick materials Check that all welding current cables are securely connected to their respective terminals 6 Connect the cooling unit if used NOTE There is a risk of tipping while transporting and storing if the welding equipment leans more than 10 Note that the stabiliser which is supplied with the unit must be fitted to increase the sta
37. ply at inputs D5 and D6 is rectified and smoothed The unregulated 12 V supply is used by the computer to sense loss of power supply and also provides a power supply to the digital instrument unit V4 is an adjustable voltage regulator which supplies 5 V for various items including the logic circuits Fuses S2 S3 S4 and S5 are 1 A anti surge 5 x 20 mm glass tube fuses 7 The display output This circuit is a buffer between the computer and the instrument unit Data to be dis played is output together with the appropriate control signals to connector H The data is decoded by the display driver in the display unit The zener diodes and series resistors protect the board against interference See circuit diagram on page 41 for details of the display unit circuitry 8 Inductor short circuiter control The inductor short circuiter ensures good starting of welding by briefly short circuiting the inductor via an external thyristor when welding starts As long as the welding torch contact is not depressed the base of transistor Q7 is held low by the control program allowing current to flow through the LED in optocoupler IC12 The optocoupler has a thyristor output which is open allowing a gate current to flow to the external thyristor via contact F1 cmva2de1 16 The base of Q7 remains low until welding current has exceeded 20 A for 100 ms When this condition is fulfilled the base goes high turning off the optocoupler and thy
38. rcuit detector sensing short circuits of the arc See also 13 No load detector senses no load open circuit voltage See also 14 and 16 28 23 24 25 26 27 28 29 30 31 cmva2de1 Control amplifier for ar arc gouging producing a DC voltage that is proportional to the reference voltage signal from 6 to give a constant voltage characteristic The shunt signal from 19 is used to provide a current limit that protects various parts of the system including the thyristor rectifier 26 Changeover switch for air arc gouging in the form of a multi position switch on the front panel which also controls selection of MMA and MIG MAG welding See 18 Main transformer three phase Thyristor rectifier Basic current resistor R4 Basic current rectifier V4 Freewheel diode V5 Shunt for measurement of welding current Inductor for smoothing welding current 29 BLOCK DIAGRAM LAR MAGMA IN MMA MODE Remote reference Power supply Internal reference Main transformer Amplifier MMA Thyristor bridge current 27 Trigger unit Amplifier air arc gouging Shunt amplifier Short circuit detector Hot start Load detector cmva2e07 cmva2de1 30 DESCRIPTION OF OPERATION CIRCUIT BOARD AP3 This description refers to the circuit diagram on page 34 The same reference numbers that were used in the block diagram on page 30 are also used
39. sconnect board contact E and slacken the pressure arm in the wire feed unit before entering the test mode K The test points to use in making measurements for each particular test are listed below for each test INPUT SIGNALS Test no 1 U ref MP4 When sweeping the reference voltage at terminals G1 G3 the display must respond with 0 255 Sweep the voltage by means of potentiometer RP1 on the power unit 2 4 12 shunt signal 0 0 102 V on B4 B3 must result in display of 0 255 Scaling is 4 A unit Apply an external voltage to the shunt input in order to simulate a current signal 0 1 V represents 1000 A 5 MP11 voltage from the thyristor bridge A voltage signal of 0 to 64 V at I1 must result in a display of 0 255 Scaling is 0 25 V unit When testing the board in the power unit the base current voltage will be obtained when the welding torch trigger is pressed 6 7 MP10 arc voltage A voltage signal of 0 to 64 V on input I2 must result in a display of 0 255 Scaling is 0 25 V unit When testing the board in the power unit the base current voltage will be obtained when the welding torch trigger is pressed cmva2de1 24 10 11 12 13 cmva2de1 Synch1 MP14 synchronising signal The display shows the number of incoming positive flanks at A1 during a period of one second i e the frequency in Hz X 1Hz When testing the board in the power unit synchronising
40. signals will be obtained when the welding torch trigger is pressed Synch2 MP13 synchronising signal As above except for A2 Synch3 MP15 synchronising signal As above except for A3 Start MPO start stop signal The display will show 111 if the start signal is detected or nothing if it is not detected Method selection only valid for LAR MAGMA The display shows 100 if input C3 is high i e when switch QF1 connects C3 to C4 When testing the power source the test is carried out with the method switch OUTPUT SIGNALS Measure these signals using an oscilloscope powered through an isolating transformer Inductor short circuiter MP21 50 Hz pulses with a pulse length of 0 5 ms should be present at inductor short circuiter output F1 Measure the signal between MP3 and MP21 with contact F unconnected The voltage on I2 must be 0 V which can most easily be arranged by disconnecting terminal I In order to ensure seal in current through the thyristor of the optocoupler the measurement probe must be of high resistance type 1 10 9 The waveform trace is shown below The decay time can vary depending on the impedance of the measurement probe No input signals are required for this test cmva2pba 25 14 cmva2de1 MP17 19 Trigger pulses mutually displaced by 120 degrees appear at outputs E1 E2 and E3 Their frequency is about 50 Hz and the pulse lengths are about 200us When measuring these signals contact E must
41. ssy uondo 788 661 8950 1 LAS LNAWNYLSNI 40 cmva2de1 CIRCUIT DIAGRAM DISPLAY BOARD 4 KRETSKORT 481793 880 gt GIN m KH gt 5 AEETI E z BENE 5 u 9 m n m o lt lt lt lt lt lt lt cmva6e10 cmva2de1 41 A quiossy uondo 088 CCI 8970 1 5 YOLONGNI A quiossy uondo 288 6150 90 IVNV LAS 42 cmva2de1 AIdUU9SSV uondo 188 161 HE 390 A QUIISSW uondo 088 028 9910 1 LINN cmva2de1 43 uondo pejunouuJ suondo 9SOU1 USUA 10615 94 eq 1SNUU eoue eq Jejunoo DIV esing 10129 0001 SI UOIUA J9ZIIIB1S eu 7 0 UBU1 9JOUU suee 1ueuudinbe y DulJO1S pue 9IIUA uidd JO SI ALON A quiossy uondo 100 8979 6 44 cmva2de1 x 5 lt 5 E 3 5 cmva2de1 rm 4 2 S Connection instruction PULSE AID Assembl
42. symbol S indicates that the power source is designed for use in areas with increased electrical hazard Enclosure class The IP code indicates the enclosure class i e the degree of protection against penetration by solid objects or water Equipment marked IP 23 is designed for indoor and outdoor use cmva2ie1 49 Mains connection Current A 6096 8096 10096 gt gt A 55 Fem m ane 46 mio me nes ato nes on lelslslslelsleleleleslsls Recommended fuses and cable areas comply with Swedish norms for rubber and plastic insulated cables Connection instructions 2101112101112 XT2 ol elo POLI XT2 li 14 230V ee 400 4 15 440 460 50HZ 50HZ TCI fof 2 0 XT2 1 500 550V SOHZ 60HZ TCI TCI cmva1pb9 cmva2ie1 50 Installation Lifting instructions The power supply should be lifted by means of its lifting eye The handle is only intended for pulling it along the ground 1 Choosea suitable position for the equipment so that cooling is not obstructed and where excessive quantities of dust moist air or corrosive fumes cannot be sucked in and so that the cooling air discharge does not interfere with the shielding gas around the welding head 2 Check that the connections on the main transformer terminal and on the control p
43. the signals are con nected to the inverting inputs of the amplifiers The amplifiers provide negative gain in an inverting mode i e the output signal is attenuated with respect to the input signal 64 V in results in an output signal of 5 V i e attenuation and inversion The thyristor bridge output voltage provides a signal for voltage control of the unit The arc voltage signal is used for various purposes including supplying a signal to the unit s digital voltmeter 3 Start and stop The start stop sensing unit is galvanically isolated from the 42 V AC incoming signal from the wire feed unit IC4 is an optocoupler with an AC input The optocoupler has an active low output i e in the absence of an input signal the output is held at 5 V by a pull up resistor and goes low in the presence of a signal Resistor R29 limits the LED current to about 10 mA while zener diodes D8 and D9 mean that a minimum voltage of about 6 V is required for the optocoupler to operate 4 Test input and method select The method select function is only used in LAR Magma Inputs C2 C3 and C4 are nor mally low When MMA welding or air arc gouging is selected C3 is connected to 25 V by a contact in OF1 The inputs are also used for test purposes see the section entitled TEST PROGRAM FOR CIRCUIT BOARD on page 24 There are three different versions of the AP1 circuit board 880 883 and 884 Version 880 has the program version P1 01 At c
44. tor 100 50 W Resistor 0 7 Base current resistor 1 1 5 Potentiometer 2 5 kQ 2 W for welding voltage control Fitted with a multi turn planetary reduction gear in the operating knob Potentiometer 2 5 k 2 2 W for welding current control at MMA and arc air gouging Shunt 600A 60mV Shunt 600A 120mV with a centre connection for 60 mV at 600 A Selector switch Remote Local control of the welding voltage Selector switch Remote Local control of the welding current at MMA welding and air arc gouging Thermal cutout The unit is fitted with a thermal overload protection cutout which protects the machine against excessive temperature rise caused by overload or inadequate cooling The cutout interrupts the control power circuit lights indicating lamp and HL2 and opens the main contactor The cutout is mounted close to the thyristors and resets automatically when the power unit has cooled Operating temperature is 93 C and the resetting temperature is 73 C See also ST4 Thermostat fitted to the rectifier cooling fins and controlling the speed of fan motor M1 by means of connection or short circuiting of capacitor C5 which is connected in series with the motor supply The thermostat operates at a temperature of 60 C closing contactor KM2 to short circuit the capacitor and allowing the fan to run at full speed The thermostat opens again when the temperature has fallen to 45 C See also ST3 Thermal switch mou
45. witches conduct with a control voltage of 15 V on pins 6 12 and 13 and are open circuit with a control voltage 010 V 15 Control power supply The control power supply is obtained from a 19 0 19 V winding on transformer TC1 The circuit board terminals B10 and B12 are supplied with 19 V respectively and the centre of the winding is connected to B5 which is the neutral in the electronic circuitry Capacitors C51 C52 and C53 decouple any HF interference Resistors R125 127 are film resistors that protect the transformer winding against any short circuits on the circuit board Together with capacitors C54 C58 they also filter out transient peaks in the 19 V supply caused by the thyristors firing Voltage regulator VR2 produces a 15 V stabilised voltage trimming potentiometer R129 provides fine adjustment Resistors R128 and R130 restrict the range over which the voltage can be adjusted to a maximum voltage of 18 V which is the maximum permissible supply voltage for the CMOS circuits D21 stabilises the negative voltage to 15 V The power rating of R131 is such as to allow the circuit to supply a load current of 30 mA 17 The trigger unit converts the DC signal from the control amplifier 16 to ignition pulses that fire the thyristors at the correct point in the cycle The unit consists of three identical sections one for each thyristor A synchronising winding on transformer TM1 connected to terminals B13 15 provides synchronising in
46. y instruction instrument set PULSE AID cmva2de1 46 oc a TE on E FEED SELECTOR c 2 FEED SELECTOR Connection instruction cmva2de1 WAL 2 y A LLIS ROV Y 5 P O E u li G 1 4 lt gt 4 QW S z co INSTRUCTIONS This chapter is an extract from the instructions for the LAR 500 and LAR 630 Technical data Permissible load at 60 duty cycle at 80 duty cycle at 100 duty cycle Current setting range MIG MAG MMA Max open circuit voltage MIG MAG MMA Efficiency at max current MIG MAG MMA Power factor at max current MIG MAG MMA Control voltage Enclosure class Application class Weight Dimensions Ixwxh Only LAR 500 630 Magma 75A 18V 500A 39V 40A 21V 450A 38V 42V 50 60 Hz IP 23 S 210 kg 856x708x990 mm 630A 44V 560A 42V 500A 39V 75A 18V 630A 44V 40A 21V 500A 40V 18 55V 55V 81 80 0 92 0 84 42V 50 60 Hz IP 23 S 230 kg 856x708x990 mm The welding power sources complies with the requirements of IEC 974 1 Duty cycle The duty cycle refers to the time as a percentage of a ten minute period that you can weld at a cer tain load without overloading Application class The
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