[DirtBound]

I have had my Powermax 45 for about 2 years now and it is the workhorse of the shop.

Recently we have had an issue where it will randomly stop the air flow and arc at the end of the cut, the next cut it will then pierce and lose the arc but the air flows until I stop the cnc table.

Then to get it to cut I have to turn off the THC and restart the line, it will start the arc and waits for the pierce delay even though it has already pierced and then starts the cut successfully.

You can see in the video when the cut ends without issue the next cut is successful.

I have tried slowing down the pierce time, lowering voltage, disabling THC and new consumables, checked the air supply for clean and pressure.

At this point I have ran out of ideas and it is getting annoying as it takes us 3x as long to cut a sheet.

I have taken a video showing the issue, you can also see the unit is not showing any error lights when it happens.

Powermax 45 issue - YouTube

Any ideas will be greatly appreciated.

Unfortunately sending it to the repair shop is not a option as we cannot shutdown the shop for 3 weeks.

[jimcolt]

I could not really tell exactly what was happening from the video. You say that the cut stops and air flow stops (do you mean that the air flow instantly stops at the end of the cut....does not stay on for 10 seconds of post flow?), then on the next cut it will pierce, then lose the arc and air flow stays on.

If the air flow stops immediately when the arc shuts off....and there are no error codes on the plasma, that means that the start/stop input to the plasma (from the THC) is bouncing. The only normal thing that will interupt the post flow air (after the cut stops) is a momemtary on/off blip from the start signal. I suggest checking the interface wiring and the start relay output from your THC. One way to troubleshoot would be to wire a switch in parallel with the start output (between the THC and pins 3 and 4 start input to the plasma)...hold the switch closed manually until the cut is finished...then release at the time the arc is supposed to shut off. If it works properly with a manual switch....then the issue is with the start signal from the THC, if it still does the same thing then the issue is withing the plasma.

Jim Colt Hypertherm

I have had my Powermax 45 for about 2 years now and it is the workhorse of the shop.

Recently we have had an issue where it will randomly stop the air flow and arc at the end of the cut, the next cut it will then pierce and lose the arc but the air flows until I stop the cnc table.

Then to get it to cut I have to turn off the THC and restart the line, it will start the arc and waits for the pierce delay even though it has already pierced and then starts the cut successfully.

You can see in the video when the cut ends without issue the next cut is successful.

I have tried slowing down the pierce time, lowering voltage, disabling THC and new consumables, checked the air supply for clean and pressure.

At this point I have ran out of ideas and it is getting annoying as it takes us 3x as long to cut a sheet.

I have taken a video showing the issue, you can also see the unit is not showing any error lights when it happens.

Powermax 45 issue - YouTube

Any ideas will be greatly appreciated.

Unfortunately sending it to the repair shop is not a option as we cannot shutdown the shop for 3 weeks.

[DirtBound]

I could not really tell exactly what was happening from the video. You say that the cut stops and air flow stops (do you mean that the air flow instantly stops at the end of the cut....does not stay on for 10 seconds of post flow?), then on the next cut it will pierce, then lose the arc and air flow stays on.

Yes that is correct. The post flow stops instantly then the next cut will pierce then lose the arc but the air stays on until I stop the cnc thus turning off the air solenoid.

I took the cover off and was watching it today and the internal leds gave some insight.
When the arc is started the first led is sold red, the xfer led is on and as soon as the arc stops the xfer led goes off and the error led goes solid red. (no leds on the operator panel are showing error)

I tested the trigger relay with a mechanical multimeter and did not notice any fluctuations during testing. I also ran though the service manual and checked the electrical system all the tests seemed to pass within spec.

[jimcolt]

The only way to shut off the postflow instantly is to blip (off / on / off) the start signal on any of our Powermax units. So the fact that the postflow is shutting off immediately tells me:

-There is a loose connection in the start circuit
-Or the start relay is bouncing its contacts when this happens (I have heard of this happening more than once, it happens very quickly so you will not see it on most meters....would likely need an ocsiloscope)
-there is some sort of intermittent issue with the control board in the Hypertherm unit.

I strongly suspect a bouncing start signal.

Jim Colt

Yes that is correct. The post flow stops instantly then the next cut will pierce then lose the arc but the air stays on until I stop the cnc thus turning off the air solenoid.

I took the cover off and was watching it today and the internal leds gave some insight.
When the arc is started the first led is sold red, the xfer led is on and as soon as the arc stops the xfer led goes off and the error led goes solid red. (no leds on the operator panel are showing error)

I tested the trigger relay with a mechanical multimeter and did not notice any fluctuations during testing. I also ran though the service manual and checked the electrical system all the tests seemed to pass within spec.