Is it the Hypertherm pm65 or the table?

[shawnbassplayer]

So I'm trying to help out our shop with an issue they're having.

We just bought a new plasma table from PPI. (we retrofited our old table into a liner cutter). Then new table was installed where the old one was. It came with a Hypertherm PM65. We are an HVAC company, so we use one of those guide plates with the ball bearings instead of a torch height control setup.

Here's the issue we're having and it's getting worse. We start cutting on 26 guage galv (happens on everything from 26 ga to 16 ga), and after a few minutes or so, the torch cuts off and raises. What's strange is when we first got the table... it cut like butter. Nice. And after a month or 2, we started having it stop cutting. We'd reset and it would go great again for a day or so. Now... We can't get through the first fitting. This happens on straights, corners, circles, etc. Everything. We've tried cutting everywhere from 45amps down to 25amps. And tried using both the fine cut and 45a consumables.

At first we were getting a 0-21 error. (We have plenty of air).... So we sent back the PM65 thinking there might be a bad circuit and had them give us a PM85 as a rental. It happened with the PM85 as well. Hypertherm says there was nothing wrong with the PM65. So we just got back the PM65 and hooked it back up.

Again we are having issues. Now it gives us a 0-20 then a 0-12 fault code. So I had our shop install a pressure guage directly at the back of the hypertherm unit. We pushed the pressure up to 120 and it sits right there while we're cutting. And it's at 120 when the machine kicks off again. So I have no idea why this would be happening.

Anyone have any ideas? We even went as far as bypassing the air filters on the compressor. Nothing.

[WyoGreen]

I'm certainly not an expert on this, but since it did it with 2 different plasma cutters, it sounds like the trouble is with the table, or the air supply. Since the air supply seems to be ruled out (as long as there isn't a moisture problem}, then we're left looking at the table. I'd think the only thing that could be going on with the table would be EMF noise on the electrical side of things. Maybe check the table grounding system. Maybe something going on with the AC supply circuits.

There's my best guesses, Steve

[jimcolt]

0-12 is Low input gas, this is sensed using an internal pressure transducer....when pressure (even momentarily) gets below 85 psi, this error shows.

0-20 is low gas pressure, and is detected internally at the electronic pressure regulator.

0-21 is "gas lost during cut", it is monitored by measuring the internal nozzle to electrode voltage....a rapid change in this voltage during steady state cutting indicates low torch plenum pressure. This shuts down the system so internal damage does not occur to the torch.

Double all of these indications with your statement that the Powermax85 loaner had the same symptoms....

I feel safe telling you, given the above 3 indications....that you have some sort of an inlet gas flow/pressure issue. You mention that you installed a pressure gauge right at the inlet, I am assuming that it is hard plumbed right to the inlet fittings on the plasma? Is there a chance that the gauge is out of tolerance? If the gauge is a few feet away...then you could have a restriction in one of your plumbing fittings between the gauge and the inlet of the plasma.

I would propose that you run a new hose of at least 3/8" ID, no longer than 50' straight from the compressor to the inlet of the plasma...remove any extra fittings that you have at the inlet, inspect them.....occasionally we will see a plumbing tee or elbow that is defective, with a very small hole that restricts air flow. The reading on the pressure gauge means nothing unless air is flowing at the torch...static pressure should always read the same as your compressor output....but when flowing (assuming your gauge is right at the inlet) you should always see a drop in pressure between the compressor gauge and the gauge you installed at the plasma, this is due to restrictions created by the length and ID of the hose as well as any fittings in the system.

Bigger hoses, shorter lengths, less fittings are all important to maintain proper flow. These systems do not use much air, however maintain pressure is key to cut quality and consumable and torch life....that is why it is so closely monitored. When using the 45 amp shielded consumables the flow rate is less than 6 cfm, less than most air tools use.

Jim Colt Hypertherm

[shawnbassplayer]

We called PPI and they are sending out a new hypertherm, torch, and a hypertherm tech to figure this out.

But just so you know where we are.... We were totally assuming that it had to be the air because of the error codes. Now realize that we had another hypertherm where this one was that worked fine. (and since we had converted it to a liner cutter, we made sure that we could convert it back for emergencies. This came in handy Friday as we were able to use it for cutting by the afternoon.)

But back to the problem. We plugged in a pressure gauge (at the hypertherm) and the air was fine. Then we bought a brand new pressure gauge and plumbed it right in the back so that we can see how the air moved while it was cutting. The gauge never dipped below 115psi... And was at 115 to 120 when the machine cut out.

We tried removing every between the compressor and the machine. Tried a different hose. I believe they even tried a different compressor. Nuthin.

I'm starting to think that maybe it has to do with the torch body? We'll see.

[shawnbassplayer]

First, it was the Hypertherm. Bad internal regulator switch on our original pm65. This caused it to read the air incorrectly and stop burning. The reason it caused all of the headaches was a combination of things.

After we sent the original pm65 out for repair, we received a loaner pm85. Unfortunately, the plasma table rep told our shop guy to run at the lowest amperage that he could, so he was running at 25ish. This caused the loaner pm85 to cut out now and then. And although it was from a different issue, it acted the same by stopping the burn and raising up as before.

Then the repair shop wasn't able to diagnose the bad internal pressure switch, so it sent it back the way it was. Again... it started cutting out and raising.

It wasn't till we got 2 techs out to see how it acted in the field that they diagnosed the switch, and that the loaner was running too low.

So now we're up and running with a new Hypertherm pm65, and at the correct amperage per the cutting chart.

[jimcolt]

Glad it got sorted out. When you said the loaner was having similar issues....that certainly made me think it had to be and external issue!


Jim Colt Hypertherm