I did try a resistor in a previous design but the wattage required for the pilot arc was rather large and much more expensive than the current sensing relay. I forgot to mention that this is a 60A plasma so a big resistor with a big heat sink is needed.
The relay (I assume you mean the contactor) is always on and the current sensing relay disconnects the 240v to the contactor when it senses a current flow in the loop through it. I did start with two coils of cable through it but it didn't work so well as it was a bit too sensitive. The single cable through it is the way the manufacture intends it to be used and it works well. I'm sure that tweaks will be made but I've not used it much yet so time will tell.After re-reading it sounds like the relay is not turning off rather than not turning on so my advice is useless anyway
Which is just what is used on a Hypertherm and other machines.
