When my compressor starts the Hypertherm shuts off the arc with a 60 error. I assume there is too much load required at the compressor at this point. I intend to upgrade the power supply which I assume will fix this??
Anyway, in the meantime I would like to stop this happening, is there a device that can deal with this initial surge and supress it so as not to cause the fault with the plasma cutter?
What amp and voltage breaker are you on? Assume on 240V with the 45XP. 50 amp breaker should cover both, but only you know the draw of the compressor you have.
If by power supply you mean the circuits that feed the compressor and plasma - then yes - it sounds like the circuit they are hooked up to is overloaded. Ideally, have the compressor on it’s own circuit. My plasma and compressor share a 50amp circuit and I’ve not had issues, but it depends on how much each device is drawing.
I doubt it’s overloaded current wise, otherwise the breaker would pop. How long is the run from the main service panel?
Tom could be right…you are either to far from the main panel…
what would really cause this is to small a gauge of wire to run both units off…
That’s right…current sag would be a better term. I’m running 50a on 6ga < 50 ft. Need to find out how big his circuit is and specs on compressor. If it’s a 30a circuit with 10g wire, then that’s likely the issue. A 50a with 8ga wire should handle most things, but depends on that compressor.
Yes it’s a 50 amp breaker on 240v, not sure what the draw on the compressor is.
The run from the compressor/plasma unit to the service panel in my workshop is about 5 meters, but the service panel is fed from the main board in my house which is probably a cable run of 30m and the cable is only 4mm2. This is something I need to address, currently I only run the Hypertherm at 30 amps maximum for that reason.
Your shop is fed with a 12awg wire?
The 4mm cable I believe is just 12GA
Yes, and it’s a long run too. I’ll be upgrading the cable, what size should I repace it with given the length do you suggest?
The compressor is 3HP, 230v 2.2kW. I think that means it will draw 10amps but I suppose the startup load is higher?
I had to look up the metric conversion…3.3 mm2 is 12ga - so that’s close enough. For 50amp you want 8ga which is 8.3 mm2. Good chance that’s your issue - sounds like your feeder line to the shop sub panel is very undersized. Be careful you don’t overheat that feeder line - what sized breaker is it on in the house? It should be a 20amp breaker on that side. I’d feed the sub panel with 6 ga (13.3 mm2).
Like james5 said I would put a 60amp feeder breaker in your main panel and run 6g out to your sub panel in your shop then from that 8g is all you would need.
That 12g though make sure it’s only on a 20amp breaker any higher then that there’s a fire risk.
It is surprising though that the breaker doesn’t trip running a plasma and a compressor.
I think the others have pretty much covered it, although, I think you need to increase the conductor size based on the distance. US National Electrical code only rates 12Ga wire runs up to 120 ft for a 3% voltage drop.
If you want a circuit for 50A, for example, you would need 6Ga as long as the run is less than 188ft, longer than that, you’d need to de-rate the cable to 4Ga.
UPDATED: Original had errors in interpreting the code table. The table was based on 120V circuits, not 240V circuits, hence the originally cited distances should have been doubled. This data has been corrected.
All good solutions her but… to get up and running now you could add a bigger air tank to store enough compressed air so your compressor does not start durring a cut. A used propane tank, 100 or 500 gallon would be almost free if you can find one would cure you problems for now. Used acetylene or nitrogen tanks that cant be charged to 2000 lbs any more would be fine to charge to 180 lbs. Check you local scrap yards.
@ctgolfer, Good suggestions! Bravo!
And, while you’re at it, put in several lengths of vertical copper pipe to dry the air! 
Yup, you betcha!
Is the US code the same for 6g at 3% voltage drop?
In canada we’re allowed a 5% voltage drop with 6g.
So at 100ft with 6g its a 3.25% drop over that length so you would end up with 116v per leg at the sub panel and that would pass here.I know every country has there own electrical code so might not pass everywhere.
HOLD ON! I messed up! There was a footnote on the table that said the numbers are based on 120V circuits. The max distance doubles for 240V circuits. SO… 6Ga should be good up to 188ft (57M) for 50A. Of course this assumes copper wire, not AL.
Sorry for the misinformation guys… 
Dang! I wish I had noticed that when I installed my Generator!!!
