Hi all,

I have a TIG welder and it has functionality to allow a high frequency arc to initiate to start the welding process. The machine is an inverter type welder.

The arc does not initiate when I depress the footpedal . the solenoid for the argon gas works fine, but no arc.

Does anyone have any suggestions on how to test and locate the issue. A microswitch operates the solenoid and hf arc.

Regards
Sam

 

Can you get a curcuit digram for it? That will be a good start.
The problem could be a lot of things, but start by checking the foot pedal switch operation and cable for breaks. It may have a couple of switches, one for the gas and another for the arc.

 

Most widespread topology of TIG is the high current SMPS going via low-pass LC filter (or coil alone), and high voltage high freq initiator voltage generator goes via rather large resistor so the current is few to dozen mA, and this is secured by high-pass filter.
The generator`s topology may be as well the Royer circuit as well the Clapp circuit, or sometimes the bloking-generator circuit. I would prefer the Clapp for it`s simplicity and brute force. The 10-20 kV is small thing for it just by good mosfet, one big and two small coils, capacitor and resistive divider, and it genuinly not demands the high-pass filter.