Dead Powermax 125

[yseguy]

So I finally upgraded from my cheapy 4x4 table to a good quality 5x10 with a powermax 125. I bought the package used, about a year old and I tested it thoroughly before I bought it and it was working fine. The hypertherm is 600v according to the seller and the sticker on the back so I had an electrician come wire it in today. At first everything was normal and the plasma cutter turned on and off normally with the switch on the back. I came back later to test it and it wouldn't turn on although I could hear a humming sound when the switch was in the on position. I had the electrician verify it was getting 600v at the input then I took the cover off and blew out all the dust. I looked for loose connections and burn marks but everything looked normal then I turned it on and verified it had 600v at the main board after the switch. I turned it off and went for dinner then I was kinda hoping the problem went away so I turned it on again with the rear switch. There was a loud pop and a bright flash and now theres a burnt spot on the large main board and it blew all 3 30 amp fuses at the main disconnect. Does anyone know why this might have happened? I dont want to replace the board only to have it blow again. Ive already contacted hypertherm about sourcing a new board and they have an excellent reputation so I know they'll help me sort it out, Im just a little disappointed that my expensive new toy is sitting idle and Im hoping it doesn't cost too much to fix.

[Rodw]

I would look at the current draw. A 30 amp circuit sounds low. If you know an old school electronics guy, it probably can be repaired. But when I recruited such a helper, we got an even bigger bang and more smoke!

[yseguy]

It draws 24amps at max load so it definitely shouldn't draw 30 to turn it on

[robertspark]

Service Manual here: https://www.hypertherm.com/Download?fil ... &zip=False

Operator Manual here: https://www.hypertherm.com/Download?fil ... &zip=False

Page 32 of the service manual states that at 600V the Input current will be 24A, however at arc stretch it could be as high as 38A, and they recommend the use of slow blow 40A fuses..... but none of this will be your problem..... (the smoke has already escaped and it was not from the fuses).


If it were me (and I have fair electronics experience and a well equipped electronics garage able to solder and desolder SMT's and reball BGA chips), I'd send it in to a service center for diagnosis and advice....

The bit that popped looks like area 17 on page 125 of the service manual which is identified as the flyback circuit

at the back of the manual is a basic layout of the power board

I'd kind of suggest that it would be time for a new power board, but you probably want to make sure the IGBT is tested as it could be the cause of your issue.

I'd be very reluctant to fiddle with it for a lot of reasons, one of which is it is 600V (phase-phase) and you won't get a second chance if you make a mistake and run your hand near something you shouldn't. That is also a whole lot of energy if something does go pop when you are facing it and testing voltages and boards, plus besides death which is final and won't be a concern of yours after the event, getting another board and just replacing it without testing the IGBT and anything else connected to it may bring back your problem on a nice new (expensive?) second board..... when it was the other device all along causing the secondary failure of the power board .... The service center should tell you fairly quick if its uneconomic to repair and its time to unfortunately bite the bullet and get another one.

[yseguy]

Thanks Robert, I found a service center nearby and I will be taking it there. I guess I was more just wondering if anyone knew what might have caused it because the machine is only a year old and Ive never even fired the torch since I bought it (used). I guess I'm partly just venting haha. Its frustrating when the most expensive machine I own is out of order when the orders are piling up

[robertspark]

Understand completely + I'd have your pain if it were me too as its a nice and very expensive machine.

I would have thought wiring would be the primary cause (incorrectly wired up).... I know your electrician is going to say no, but as you and him are the only ones stood next to the machine you are the only ones who can check....

if it were me, I would have checked the Phase to phase voltage and verified it was 600 volts between each of the phases {I don't know what you call the phases in your locality, they could be L1, L2, L3, Red, Yellow, Blue, R,Y,B or brown, black and grey)

I would then check the voltage between each of the phases and the earth connection point on the hypertherm, it should be ~ 346V between each of the phases and earth (or neutral).

The powermax 125 is 3-phase and earth (no neutral.... but neutral "should" be the same voltage as earth {or very close to it}.... depends upon the local earthing / grounding arrangement.

I do not believe that the phase orientation affects the powermax 125, given it is rectified and then is used as a DC (direct current) voltage via the IGBT.

given it was / is running at 600V, i would have got something like a long plastic bottle brush (and after it was isolated and left to discharge its capacitors.... I think the recommendation tends to be several hours {check the service manual, think this is recommended annually + it will give the discharge time for the capacitors}) I would have brushed the inside and blew it out with a long air compressed air nozzle just to make sure that there was little to know metalic dust within it.... but that is just me...

If the machine was running on only two phases (i.e. the wiring was not terminated correctly.... if you were using a plug in receptacle) I would have thought that the 3-phase rectifier would not have been happy with the load ..... but this would be after some use..... but it "should" have popped one of the fuses given it would have been attempting to draw more than 24A per phase if it was only running on two phases...... again none of this actually fixes the PMX.... but it may be worth checking {again}..... if you still have the case off and you can safely get to the terminals on the power board, I'd measure the voltages there with the power on.... (Phase-Phase {each of them} and phase to chassis earth {each of them}..... that would rule out a 2-phase wiring problem.... and it would be all down to the machine at that point.

Good luck ..... let us know what your service center say

[yseguy]

I have to go out and get some more fuses tomorrow but before it blew I checked and made sure it was getting 600v at each of the phases and I already blew it out after the first time it wouldn't turn on. Im thinking there must be a short circuit in there somewhere as thats the only thing I can think of that would draw so much power at idle seeing as it blew immediately after I turned the switch on, its just odd that it happened randomly when nothing had changed since the last time I turned it on. We'll see what the service centre has to say and worst case scenario theres a powermax 105 for sale a few hours away I could swap in and at least I could still use my hyamp machine torch

[yseguy]

Well I got an email from technical support and they're going to replace the board under warranty! Hopefully thats the only problem but when I drop it off at the repair centre I'll request that they check the IGBT and generally go through it

[djreiswig]

Glad to hear Hypertherm is going to help you out. Their service is top notch.

[yseguy]

Well its been at the repair centre for a couple weeks and I should have it back soon. Apparently there was major internal damage but they dont know the cause. They're replacing a bunch of parts including the board and said it would have cost over $4k if it werent under warranty

[ctgolfer1]

Damn man, you dodged a bullet there, how long is the warranty on those machines?

[yseguy]

It has a 3 year warranty and Ive got 2 years left. I got it back today free of charge which was nice. I hooked it up again and it had a code that said torch not connected so that ended up being a connection that wasnt quite plugged into the board. Now the main problem is the torch wont fire at all. I tried from the computer, with the remote pendant, jumping pins 3 and 4 at the cpc connector and jumping the pins they go to on the main board. The machine is running normally with no error codes but nothing happens when its triggered. No gas flow, no arc, nothing. Í can do the gas flow test and that works fine.

[yseguy]

I finally got it fixed. I looked at those pictures I took earlier and I realized one of the connectors on the board was plugged in backwards. Even the dealer makes a mistake sometimes but Im just happy to have it working again. I was cutting some 1"plate and its definitely the nicest air plasma Ive ever used

[AREA]

WOW, impressive cut for sure