CIGWELD WeldSkill 200AC/DC, Руководство по обслуживанию

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Troubleshooting 6-16 Manual 0-5206
WELDSKILL 200AC/DC INVERTER TROUBLESHOOTING
2 Output Current Calibration
Select STICK process and DC mode on the front panel.
Measure no load output welding voltage and adjust WVF potentiometer so Volts display reads within 0.1V of the
measured value.
Select TIG process and DC mode on the front panel.
Connect a load to the output terminals. The load should be of a resistance to give 18V at 200A.
Set front panel AMPS potentiometer to maximum.
Adjust Imax trimpot until output amps is 200A +/-0 2A
Set front panel AMPS potentiometer to minimum.
Adjust 0V (SW100) trimpot until output amps is 5A +/- 0.2A
Repeat the minimum & maximum calibration until both are within tolerance
Set front panel AMPS potentiometer to maximum.
Adjust A potentiometer so Amps display reads within 0.5A of the measured value.
6.12 Main Circuit Description
!
WARNING
Turn off power and disconnect mains supply plug from receptacle before working on the unit. Allow
two minutes for capacitors to discharge after disconnection from mains supply voltage.
The mains supply voltage is connected via a double pole switch to the input rectifiers on the main inverter board
through an EMC filter. Overvoltage protection is provided by varistor CY1.
The rectifier output charges the main capacitor bank (C5, C6, C7, C8, C9 and C10) to high voltage. Inrush current
limiting is provided by a PTC which is then bypassed by relay J1 after a few seconds.
The primary igbt transistors (T3, T4, T5, and T6) switch the transformer primary at high frequency and varying
duty cycle. The transformer return wire is taken from the terminal ZBQY1 (the voltage at this point is approximately
half the DC bus voltage).
Secondary output voltage from the transformer is rectified by the output diodes (D1, and D2) to DC. This DC is
controlled by the PWM of the primary side igbt transistors, and is filtered by an inductor before connecting to
the welding output terminals. IGBT1 to IGBT8 control whether AC or DC output is sent to the welding terminals.
A thermal overload device (thermal switch) is fixed to the rectifier heatsink. When an over temperature occurs,
the control circuit inhibits the trigger, gas solenoid, and the welding output. The thermal overload indicator LED
on the front panel is illuminated.
The current transformer CT1 provides a signal to the control circuit to indicate both transformer primary current,
and also detect transformer saturation. The Hall effect current sensor CT2 is powered from reg & - 15VDC
supplies and provides a voltage signal proportional to the output welding current to allow the control circuit to
regulate welding current.