ESAB LKB 400W, Руководство по обслуживанию

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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.
•
Power supply to the electronic circuitry
-
the +26V power supply from V3 through R3 – is regulated to 15V by voltage regulator A1,
- +15V is used for powering of motor control electronic
•
+60V power supply is used for motor control,
This voltage may vary (with load/mains voltage deviation) – from –15% to +10%.
• +26V (intermediate voltage for A1) – is also used for powering of relays K1 and K2 (on PCB) and for input
control circuit (“START/STOP”).
3. 1.2 START/STOP
Closing contact S1 on the welding torch starts the welding process – or only motor M3 depending on control
mode selection (see – section 3.1.3)
3. 1.3 CONTROL MODES – 2-STROKE/MOTOR-TEST/4-STROKE
By the switch S3 on the PCB (pos. M) – in the motor compartment – welder may select the following control
modes:
A) 2-STROKE CONTROL
When the trigger switch (welding gun-S1) is depressed – welding process starts (wire feed motor, gas
valve and power unit contactor).
When trigger switch is released – welding process stops (motor and gas valve – immediately, contactor –
when burnback time is elapsed).