PM-205 Plasma not working

[jas329]

Got the picture of the 2nd electrode that seems to be burning up, the right set is from yesterday and the left is from today, I stopped after seeing it start to pit in the center. I can't cut more than 6" before the electrode burns up and looking at the cost of getting new electrodes and cutting tips, it would cost me a fortune to cut anything. I think I'm going to hold off for a while with the plasma cutting until I can figure out whats going on.

[everlastsupport]

Jas329,

Can you PM me a phone number. I need to ask some questions. The center wear is normal over time.

[performance]

It is possible that there is a defect in the torch. If the piston isn't pushing in all the way, it would cause a constricted arc and cause radial melting if the tip wasn't fully retracting.

Push in on the electrode and see how far it give when it goes in. Also see how fast it returns. Watch for any binding or freezing up of the piston mechanism.

The torch ignites an arc when the electrode is "blown" back by the flow of air pressure. The electrode is spring loaded and acts as a "piston" to go from a grounded condition to an open position, creating a spark gap. The basic concept is the same in breaker points ignition on a vehicle, where the spark jumps across the air gap when the points open. However in this cause, the spark generated ignites the plasma stream (sort of star trek sounding, I know, but that is really basically what happens).


Just as points that don't have good gapping will burn, this seems to be a similar situation. Its possible also that a hose is kinked inside the machine and its preventing full air flow to the torch, causing a reduced gap.

Now, of course, Mike is the electronics expert, but having a lot of experience with that torch, I am only offering some things to check.

[jas329]

Mike PM Sent.

Mark, when everything is screwed tight, the cup compresses the electrode against the tip and there is no movement in the tip. When not in use the electrode makes constant contact with the cutting tip. It looks like tip can be pushed back about 1/16" before the swirl ring makes contact with the torch body where the electrode screws in.

Just pushing in the electrode by itself it has about 1/4" travel. looking at the small holes for air flow near the electrode, when the swirl ring and tip is compressed against the electrode it seems like the holes are almost covered up by the torch body. when the electrode is fully compressed in agianst the torch body the holes are completely covered up.

The spring return on the electrode is decent, seems a little rough/rubbing when pushing it in though.