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ESAB LHF 405 PIPEWELD, Service Manual

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ESAB LHF 405 PIPEWELD Service Manual Download Page 18

Edition 071024

-- 18 --

smlhfpw1

LH20/1:9 Thermal overload circuit

The circuit co--operates with NC thermal switches connected in series. Opening of
any of them (placed on the transfer or the rectifier) switches the V1 transistor on.
Closed the V1 transistor switches on the H1 indication lamp and disables thyristors
firing.

Summary of Contents for LHF 405 PIPEWELD

Page 1: ...0349 300 070 Valid for serial no 422 423 xxx xxxx 071024 LHF 405 PIPEWELD LHF 615 PIPEWELD Service manual...

Page 2: ...ess remote current control receiver 15 LH20 1 6 Power supply 16 LH20 1 7 Regulator and current shunt amplifier 16 LH20 1 8 Synchronisation and thyristors firing 17 LH20 1 9 Thermal overload circuit 18...

Page 3: ...epair 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 INTRODUCTION LHF 405 615 PIPEWELD are...

Page 4: ...nt 70 74 Enclosure class IP 23 IP 23 Application class Weight 215 kg 303 kg Dimens lxwxh 1310 765 705 1310 765 705 Duty cycle The duty cycle refers to the time as a percentage of a ten minute period t...

Page 5: ...160_C C1 Capacitor 2 F for cooling fan C2 C3 Capacitor 0 1 F H1 Indicating lamp white H2 LED yellow on when thermal overload is activated i e when one or both of thermal switcjes B1 and B2 are open L...

Page 6: ...male X02 Remote control socket X10 Mains terminal block X20 Terminal block X40 Terminal block X45 Terminal block XF20 Contact 15 pole female XF30 Contact 9 pole female XF40 Contact 12 pole female XK1...

Page 7: ...Edition 071024 7 smlhfpw1 LHF 405 PIPEWELD...

Page 8: ...160_C C1 Capacitor 2 F for cooling fan C2 C3 Capacitor 0 1 F H1 Indicating lamp white H2 LED yellow on when thermal overload is activated i e when one or both of thermal switcjes B1 and B2 are open L...

Page 9: ...male X02 Remote control socket X10 Mains terminal block X20 Terminal block X40 Terminal block X45 Terminal block XF20 Contact 15 pole female XF30 Contact 9 pole female XF40 Contact 12 pole female XK1...

Page 10: ...Edition 071024 10 smlhfpw1 LHF 615 PIPEWELD...

Page 11: ...LH10 2 PCB makes up a primary voltage reference for current setting circuit and for digital meter Current setting reference voltage 10 7V is derived from 1 23V by the amplifier made of A2a V30 C14 R4...

Page 12: ...al is shorted to ground and current signal is transfered to HI input of ICL7107 When Q4 is set to V then gates of transistors V33 and V34 are on 5V potential thus current signal is shorted to ground a...

Page 13: ...signal shows up on the non inverting input of the A4a The capacitor C16 is charged via resistor R21 and the potentiometer of the HOT START time setting Time required for charging the C16 up to 10 7V...

Page 14: ...en untill trigger on welding torch is pressed After trigger is pressed rectifier bridge VB2 is supplied from transformer T2 winding via voltage divider R60 R61 Consequently transoptor VC1 is turned on...

Page 15: ...ed signal is processed in pulse selector and separator what serves for RESET and COUNT pulses identification COUNT pulse duration is proportional to welding current value Gate D3a generates pulse that...

Page 16: ...0 1 7 Regulator and current shunt amplifier The feedback signal from the current shunt is amplified by the rate of 50 in the differential amplifier made of the A1 operational amplifier and resistors R...

Page 17: ...comparator make up synchronised ramp generator The amplitude of the ramp is adjusted by means of the R71 58 45 potentiometer Ramp voltage is compared with the output voltage of the regulator in compa...

Page 18: ...uit The circuit co operates with NC thermal switches connected in series Opening of any of them placed on the transfer or the rectifier switches the V1 transistor on Closed the V1 transistor switches...

Page 19: ...Edition 071024 19 smlhfpw1 LH20 1 Components layout...

Page 20: ...Edition 071024 20 smlhfpw1 LH10 2 Components layout...

Page 21: ...EWELD d put the jumper back from ZW2 to ZW1 and set S3 to INT 5 Voltmeter calibration a set the V A switch on machine front panel to V voltage measurement b connect reference voltmeter to machine outp...

Page 22: ...e ARC FORCE knob to maximum load the power source to achieve 24V voltage on output e gradually increase the load following the voltage starting from the threshold of 18 5V actual output current should...

Page 23: ...ge comes into contact with a component or assembly that is grounded A rapid discharge can occur causing damage This damage can take the form of immediate failure but it is more likely that system perf...

Page 24: ...hin radius of 10mm or less from broken thermostat If it s possible and safe for transformer winding broken thermostat may be removed Then the spare thermostat is to be mounted right in place of broken...

Page 25: ...th S its operation S location of emergency stops S its function S relevant safety precautions S welding 2 The operator must ensure that S no unauthorised person is stationed within the working area of...

Page 26: ...ble to the rectifier according to the relevant regulations and install a suitable fuse in the main fuse box S Make sure the welding rectifier is not covered or positioned so that cooling is obstructed...

Page 27: ...he mains cable areas and fuse sizes as shown above are in accordance with Swedish regulations They may not be applicable in other countries make sure that the cable area and fuse sizes comply with the...

Page 28: ...Edition 071024 28 smlhfpw2 Assembly of components...

Page 29: ...urrent should be set with knob on remote control unit that should be connected to terminal 11 c if the switch 7 is set to EXT2 remote wireless current setting the current should be set with use of rem...

Page 30: ...IG welding Set switch 6 to In TIG mode output voltage of machine is ON after the welding torch switch is pressed After arc initiation current rises from minimum possible value until it reaches the val...

Page 31: ...s arc time disposition and the surrounding environment It will normally suffice to blow the power source clean using compressed air reduced pressure once a year If the power source is very dirty brush...

Page 32: ...32 notes NOTES...

Page 33: ...33 notes...

Page 34: ...92 22 ESAB international AB Gothenburg Tel 46 31 50 90 00 Fax 46 31 50 93 60 SWITZERLAND ESAB AG Dietikon Tel 41 1 741 25 25 Fax 41 1 740 30 55 North and South America ARGENTINA CONARCO Buenos Aires...

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