Hello together,

we have bought a cr electronic plasma cutting with a hypertherm hd3070 plasma source and HPR130 torch upgrade. After a lot of work everything was running smooth.

But after a while there were coming up some start problems of the plasma arc. At the beginning the arc needed a few more tries to start but now the arc doesn’t start anymore.

When we give the start signal, the “DC on” lamp at the front of the power source lights up and the gases flow towards the torch. At the high frequency box we can clearly see a spark and at the torch sometimes we can see a small spark, too but not really a well pilot arc.

We already replaced the pilot arc relay and we cleaned and checked the spark gaps at the high frequency box. Also we have checked the gas flow towards the torch and we changed the wear parts.

A check of the open circuit voltage showed 268V and the green LED on the chopper lights up after the start command. At the filter in the high-frequency console we measure permanently 120V after the power source is switched on. If we check the voltage behind the filter it is only 78V!?

The green active LED on the pilot arc circuit assembly sometimes lights up for a very short time after the start command. About the pilot arc assembly group we can not find any further information in the user manual and how to check it. We also don’t know how to find the pilot resistor and which resistant value it should have.

Maybe someone have any ideas what the problem could be or what we can check to determine the failure?

Thanks in advance!

BR
Michael