ESAB Powercut 875 Instruction Manual page 211

sectIon 5
f. high frequency and pilot arc are on but main arc does not transfer.
1. Make sure work clamp is connected to work material.
2. Check the torch. Replace consumables if necessary.
3. Make sure the current setting potentiometer is set above 20 amps. If it is, set below 20 amps, then HI FREQUENCY
will go on and off at 5 sec intervals.
G. poor cutting performance.
1. Check air supply regulator . It should be adjusted to 65-75 psig.
2. The air supplied to the torch should be free of oil and water.
3. Make sure the consumables in the torch are acceptable.
4. Check open circuit voltage. See E.4 above.
5. Check the output. Use a calibrated current probe capable of measuring 100 amps in the presence of high frequency.
h. air does not shut off.
1. Check air test, the gas solenoid valve is energized when the switch is in the "on" position.
2. Does air flow stop when the torch switch is unplugged? If yes, check and repair the torch. If not, send unit to an Au-
thorized Repair Station for repair.
a. Check voltage to solenoid coil, if present when torch switch is unplugged, replace PCB1. If voltage is "0", replace
solenoid valve.
I. main arc is difficult to start.
1. The most common reason is worn or missing consumables. Check and replace if necessary.
2. Input air must be clean and dry.
3. Input air pressure must be at least 75 psig.
4. Torch connections must be tight.
5. Work cable and clamp must be in good condition and must make a good electrical connection to the material to be
cut.
6. If above items check OK , the problem is internal. Send unit to an Authorized Repair Station for repair.
a. Missing or weak pilot arc. Check pilot arc fuse, open circuit voltage, pilot arc resistors and pilot arc wiring.
b. Inoperative starter board (PCB-5).
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