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ESAB LKB 400W Service Manual

Welding rectifier
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LKB 400W
WELDING RECTIFIER
Service manual
0349 300 020 01-01-24

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Summary of Contents for ESAB LKB 400W

  • Page 1 LKB 400W WELDING RECTIFIER Service manual 0349 300 020 01-01-24...

  • Page 2: Table Of Contents

    1. CONNECTION DIAGRAM, LKB400W ....................4 2. COMPONENT POSITIONS, CIRCUIT BOARD LA07 (A1) ..............6 2.1 DESCRIPTION OF BOARD LA07....................8 3. COMPONENT POSITIONS, CIRCUIT BOARD LKC31 (A2) ............. 9 3.1 CONTROL CIRCUIT FUNCTION LKC31 ..................10 3.1.1 POWER SUPPLY ........................10 3.1.2 START/STOP ..........................
  • Page 3 ! WARNING ! ARC WELDING AND CUTTING CAN BE INJURIOUS TO YOURSELF AND OTHERS. TAKE PRECAUTIONS WHEN WELDING. ASK YOUR EMPLOYER FOR SAFETY PRACTICES THAT SHOULD BE BASED ON MANUFACTURER’S HAZARD DATA. ELECTRIC SHOCK - Can kill - Install equipment in accordance with obligatory standards. - Do not touch live electrical parts or electrodes with bare skin, wet gloves or wet clothes.

  • Page 4: Connection Diagram, Lkb400W

    CONNECTION DIAGRAM, LKB400W, 400V Switch positions for switch Q3 Switch positions for switch Q4 COMPONENT DESCRIPTION Circuit board LA07 Circuit board LKC31 Pump V/A - meter Drive unit motor Transformer Rectifier bridge Diode bridge B1,B2 Temperature switch Inductor Flow switch Shunt Wire speed reference potentiometer Contactor...
  • Page 5 LKB 400W, 400V...

  • Page 6: Component Positions, Circuit Board La07 (A1)

    2. COMPONENT POSITIONS, CIRCUIT BOARD LA07 (A1)
  • Page 7 DIAGRAM LA07 (A1)

  • Page 8: Description Of Board La07

    DESCRIPTION OF BOARD LA07 (A1) Power supply The board is supplied 20V AC voltage (contacts 8,9 connector X1). Two step voltage regulation (elements T9, U1) provide voltage 15 V ± 5% required for control system power supply. Inputs 1. Auxiliary contact of main contactor type NO - 11,12 X1, 2.

  • Page 9: Component Positions, Circuit Board Lkc31 (A2)

    COMPONENT POSITIONS, CIRCUIT BOARD LKC31 (A2)

  • Page 10: Control Circuit Function Lkc31

    3.1 CONTROL CIRCUIT FUNCTION LKC31 Sections 3.1.1-3.1.6 below refer to the diagrams in chapter 1. 3.1.1 POWER SUPPLY The circuit board uses one supply voltage: 42VAC – rectified by the bridge V2 for power supply to the motor and control circuitry. •...

  • Page 11: Wire Feed Speed

    B) MOTOR TEST When trigger switch is closed – only feed motor starts, gas valve and contactor remain disenergised. C) 4-STROKE CONTROL The welding process is controlled by trigger switch S1 (welding gun) – as shown below: NOTE: On the LKC31 – for selected 2-S/4-S mode – active signals are high! 3.1.4 WIRE FEED SPEED The wire feed speed setting range is 1,6 to 25 meter/minute, the upper speed may be adjusted by R6A, minimum speed is adjusted by R15A.

  • Page 12: Motor Control/Dynamic Braking

    3. 1.5 MOTOR CONTROL/DYNAMIC BRAKING The motor is powered by the smoothed +60 V supply. Pulse width modulation of transistor V6 controls the motor voltage. The pulse frequency is about 16 kHz, and maximum conduction time of the pulses is about 95% of the pulse cycle time.

  • Page 13: Burnback Time, Contactor, Gas Valve

    3.1.6 BURNBACK TIME, CONTACTOR, GAS VALVE • BURNBACK TIME The burnback time is the time from when motor braking starts until the main contactor opens. The burnback time can be adjusted from 0 to 0,35 seconds – by the potentiometer R71. (R71 is located in the drive unit –...
  • Page 14 Voltage indication is adjusted by potentiometer R1 on the PCB – comparing with reference voltmeter at the input. (Note: voltage adjusting is to be made only when jumpers are properly located and U-REF setting is completed!) Recommended voltage metering range is: 0V to –40V. (Calibration is performed for –25V). Recommended current input range is: 0mV to +60mV.

  • Page 15: Technical Data

    4.TECHNICAL DATA Mains voltage 400V-415V 3~ 50Hz Mains cable cross-section 4x4mm Mains fuse 25 A delayed Rated power consumption 18,8 kVA Rated primary current @ P35% 26 A Rated welding current Duty cycle* 35% 400 A Duty cycle* 100% 237 A Welding current range 30A÷400A Open circuit voltage...

  • Page 16: Installation

    Fuse, slow-blow 7. INSTRUCTION FOR USE The LKB 400W is step-switched welding power unit, intended for welding with solid filler wires of steel, stainless steel or aluminium, and cored wires with or without shielding gas. The power units can be fitted with an instrument for display of current and voltage. It incorporates a sample- and-hold function.

  • Page 17: Cooling Circuit Diagram

    F. DIGITAL METER indicates actual values of welding current and voltage. Required value is obtained by setting lever of the switch to a proper position. Semi-automatic welder LKB 400W is manufactured without meter. Meter is delivered with necessary equipment and assembly instruction KIT (meter has HOLD function).

  • Page 18: Maintenance

    5. Disconnect current cable (+) from the bridge. 6. Connect shunt with reducing sleeve and bridge, and next connect current cable (+) to free end of shunt. 7. Connect wiring of meter according to schematic diagram of LKB 400W. 1. Meter VA-MET12 2.

  • Page 19: Spare Parts List

    11. SPARE PARTS LIST Ordering No. 0349 302 111 LKB400W 400V-415V 3~ 50/60Hz 0349 302 156 LKB400W 230V 3~ 50Hz Item no. Ordering no. Denomination Notes 400V-415V 230V 0349 302 135 Front grill 0349 302 134 Front panel 0349 302 137 Panel 0349 302 149 Rotary cam switch...
  • Page 20 Item no. Ordering no. Denomination Notes 400V-415V 230V 0457 290 042 Temperature switch (90 0349 302 048 Temperature switch (135 0349 302 143 Transformer 0349 302 205 Transformer 0349 302 206 Transformer with switches 0349 302 207 Transformer with switches 0349 302 144 Inductor 0349 302 145...
  • Page 21 Item no. Ordering no. Denomination Notes 400V-415V 230V 0469 834 881 Feed unit 0349 302 148 Circuit board LKC31 0349 302 152 Contactor 0349 302 192 Contactor 0349 302 153 Control transformer 0349 302 027 Circuit breaker 0349 302 193 Circuit breaker 0146 967 881 Brake hub...
  • Page 23 Item no. Ordering no. Denomination Notes 400V-415V 230V 0349 302 030 Fuse element 0349 302 032 Fuse element 0349 302 031 Fuse element 0349 302 138 Gas valve 0349 302 139 Rear shield 0349 302 195 Rear shield 0457 289 032 Cable gland 0457 290 079 Cable gland...
  • Page 24 Item no. Ordering no. Denomination Notes 300a 0469 833 880 Pressure arm, left Contains items 301, 302, 303, 304 and 305, one of each. 300b 0469 833 881 Pressure arm, right Contains items 301, 302, 303, 304 and 305, of each. The same items as 300a, they are only fitted differently.
  • Page 26 ESAB subsidiaries and representative offices Europe NORWAY Asia/Pacific Representative offices AS ESAB AUSTRIA AUSTRALIA BULGARIA Larvik ESAB Ges.m.b.H ESAB Australia Pty Ltd ESAB Representative Office Tel: +47 33 12 10 00 Vienna- -Liesing Ermington Sofia Fax: +47 33 11 52 03...

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