Loss of arc and melted earth lead!

[weldergirl]

hi all!
Yesterday (9.1.23) our workshop plasma - hypertherm powermax 125 - had some issues.
Was running and cuting perfectly on some 16 mm plate - after cutting went to change to some 3mm plate (changing all appropiate consumables settings etc.) and it has run through the motions of cutting with NO ARC.
Tried again a few times and would not arc - upon furher inspection the EARTH LEAD HAS MELTED into the unit.
pulled apart earth, got rid of melted plastic and fixed but still will not arc!

Gone through all trouble shooting, talked to electrican and support over the phone - no one can figure out why runs everything else smoothly but no arc/cut

thought maybe control cord but tested with manual jumper and reads as working

please help!
thankyou, brooklyn

[adbuch]

I would test it using a hand torch to make sure the plasma cutter is working. If the answer is "yes", then move on to the interface between the cutter and table.
David

[weldguy]

The Hypertherm 1/4 turn lock in ground leads have been the source of many problems in my experience but I have not seen this one. Problem is they can come loose and I am guessing in your case being a higher amperage machine the poor connection has created excessive heat build up at the connection.

You say you tested it with a manual jumper and it is working...so can you get an arc when you manually jump it?

[acourtjester]

With the lead pulling high current which would cause the lead to over heat, I would suspect lots of arcing toward the end. This would have traveled to other places in the Plasma unit, resulting in blown electronics. I think repair or replacement is in order

[adbuch]

With the lead pulling high current which would cause the lead to over heat, I would suspect lots of arcing toward the end. This would have traveled to other places in the Plasma unit, resulting in blown electronics. I think repair or replacement is in order

Tom - that is why I asked if they could still cut in manual mode. I would start there.
David

[weldergirl]

hi great news!

New control cable arrived today ( cord between control box and plasma unit) - plugged it in ran a test cut and immediatley cut YAY

thankyou all for your suggestions - all very helpful

rooklyn.

[adbuch]

hi great news!

New control cable arrived today ( cord between control box and plasma unit) - plugged it in ran a test cut and immediatley cut YAY

thankyou all for your suggestions - all very helpful

rooklyn.