PP256 goes high and low with output

[BlownBlueZ06]

I have the PP 256. When I'm cutting, it will all of the sudden greatly increase the plasma arc and cut much better. It will go like that for a second and then go back to the lower arc for another 10 seconds. I have verified all of the settings and connections. I am running 60psi pressure through the regulator and have tried increasing and decreasing pressure with no change in operation. The TIG torch operates smoothly with no change in output current.

[ingvey]

is the tip clean I had a problem becuase I held it too close and got molten Al on it when I was cutting Other than that I have had no problems with my PP256

[performance]

Ok,
Typically a problem like that is either in the consumables, being loose, worn out or mismachined, OR you have a bad connection to the metal with your work clamp. Did this start after changing consumables?

With the work clamp, I have seen issues from time to time with corrosion or other problems with the work clamp. IF you have another cable change it out. You could even use your stick electrode holder as a temporary cable and clamp depending upon which holder you have. Also if the surface is rusty or painted, you will need to grind a spot to make good contact. I have seen it work with tig and not plasma. There are higher voltage/resistance issues at play.

[BlownBlueZ06]

Ok,
Typically a problem like that is either in the consumables, being loose, worn out or mismachined, OR you have a bad connection to the metal with your work clamp. Did this start after changing consumables?

With the work clamp, I have seen issues from time to time with corrosion or other problems with the work clamp. IF you have another cable change it out. You could even use your stick electrode holder as a temporary cable and clamp depending upon which holder you have. Also if the surface is rusty or painted, you will need to grind a spot to make good contact. I have seen it work with tig and not plasma. There are higher voltage/resistance issues at play.

Thanks for the help. I was cutting clean stainless pipe the other day when I had the issue. I cut some steel today and had the same issue, so I changed the tip and cup and it seems to be better. I didn't cut much material with the new consumables installed though.
Thanks again

[BlownBlueZ06]

is the tip clean I had a problem becuase I held it too close and got molten Al on it when I was cutting Other than that I have had no problems with my PP256

Any time that has occurred, it put the machine in protect mode. I reset the machine and clean the cup and all is well.

[performance]

Stainless doesn't necessarily mean a good connection on the cable or the clamp. In fact, with its high electrical resistance, it can show up a problem where it wouldn't on other type materials.

[Wrenchtamer]

I have a 256 and the symptom you are describing to me sounds like the pilot arc kicking back on. Personally I have founf that standoff and travel speed affect it greatly. Both of which relate to what Mark said, make sure your connections are good. you could leave the ground completely off with the plasma and there is chance you might not even notice. At least I have done this when cutting multiple sections judt forgot to switch the ground over.

[BlownBlueZ06]

I changed tip and cup and inspected the ground cable and clamp closely and saw no issues. It then wouldn't even start the arc until I loosened the cup, which gives me the impression that the tolerances between the two components are too tight. I was cutting a piece of cleaned aluminum and still have the issue. Before pulling the trigger, the display will read a number like 40. then when I pull the trigger, the display reads 25 and won't change until the post-flow is disengaged.

[performance]

Blown, it does sound like a consumable issue. Just give us a call, and we can probably make quicker work of it over the phone.

[Timberwolf]

Hey Mark, what ever came of this? I've had the same thing on my 256 and it may have been an issue with the ground, but not real sure. I've only used the plasma 3 times and with the same consumables that came with the welder. I may look into it later if I get some time today.

[performance]

I haven't heard, or at least don't remember talking to anyone directly. It could be that he talked to someone else did though.

[ChadP]

My pp205 does the same thing and the consumables were barely used. Mine even kicks on and off. I hope the consumables last longer the 5 inches of cutting.

[performance]

Chad,
Describe your symptoms a little more. What side do you have your torch in?

[ChadP]

Chad,
Describe your symptoms a little more. What side do you have your torch in?

Torch is in negative side. When I cut the flame cuts out I can hear a clicking in the torch. It will click and it goes off then it will click and it comes back on. The weird thing is itif I hold it in midair it stays on. Make sure your consumables are tight inside.

[performance]

It's the plasma blowback resetting. It could be an air supply problem.

[ChadP]

It's the plasma blowback resetting. It could be an air supply problem.

I have a 30 gallon comp 150psi max. My regulator is about 60 lbs I've tried more and less. Why would the blowback do that, could the torch have a problem internal. I've tried 3sets of consumables I checked they are tight.