Arc OK intermitent issues on torch fire

luftlupus wrote: You some kind of prophet?

Nope, just experience.
You are welcomed, always.

Just as info in one place, in case the air starts but there is no pilot arc and subsequently no cutting, check in this order:
-Air pressure while the air is running, should be 4.5 to 5.5 bar,
-Check if the consumables are properly seated/tightened,
-If the consumables are used, change them, even if they still look usable, the black stuff that collects there will in some cases prevent a pilot arc.
In case all of the above fails, find some thin wire about 1cm in length and insert it in the nozzle orifice leaving one part protruding out, carefully set the torch so the wire is in contact with some scrap material then press the trigger to fire the torch while slowly moving the torch over the material.
The above last past is to check if the pilot arc and the high power parts of the plasma source are working, if the procedure works and produces a cut then the high power part is ok and there is a failure in the pilot part of the machine.
Also the above is valid for plasma sources having separate electronics for pilot and cut, does work even for blow back torches to reveal if the power stage is ok leaving the only culprit the electrode/spring or torch seat for them.

tommylight wrote: Just as info in one place, in case the air starts but there is no pilot arc and subsequently no cutting, check in this order:
-Air pressure while the air is running, should be 4.5 to 5.5 bar,
-Check if the consumables are properly seated/tightened,
-If the consumables are used, change them, even if they still look usable, the black stuff that collects there will in some cases prevent a pilot arc.
In case all of the above fails, find some thin wire about 1cm in length and insert it in the nozzle orifice leaving one part protruding out, carefully set the torch so the wire is in contact with some scrap material then press the trigger to fire the torch while slowly moving the torch over the material.
The above last past is to check if the pilot arc and the high power parts of the plasma source are working, if the procedure works and produces a cut then the high power part is ok and there is a failure in the pilot part of the machine.
Also the above is valid for plasma sources having separate electronics for pilot and cut, does work even for blow back torches to reveal if the power stage is ok leaving the only culprit the electrode/spring or torch seat for them.

Will add this to my notes. cheers

tommylight wrote: Last post first schematics shows a wiring error that will cause the ARCOK (transfer) to short the VFIELD power.
I really hope it is not wired like that.

Are you referring to the cap going across the pos and neg, rather than being inline on the pos?

Do you have an opinion on using a resistor vs cap in this setup?

I am currently wiring my hypertherm pm85 and my head is about to explode from all of the (well intentioned) conflicting information I am getting. It reminds me of conversations/debates/arguments I have witnessed over the years between master electricians and electrical engineers. "You can't do that! It will NOT work!!!" ... "That's interesting, I've been doing it like that for 30 years!!!" etc etc

txtrone wrote:

tommylight wrote: Last post first schematics shows a wiring error that will cause the ARCOK (transfer) to short the VFIELD power.
I really hope it is not wired like that.

Are you referring to the cap going across the pos and neg, rather than being inline on the pos?

Do you have an opinion on using a resistor vs cap in this setup?

I am currently wiring my hypertherm pm85 and my head is about to explode from all of the (well intentioned) conflicting information I am getting. It reminds me of conversations/debates/arguments I have witnessed over the years between master electricians and electrical engineers. "You can't do that! It will NOT work!!!" ... "That's interesting, I've been doing it like that for 30 years!!!" etc etc

In the diagram that post is referring to, the field power + side is wired directly to the input for arc ok. It was a mistake in the diagram.

As for resistor vs cap, it’s two different ways to skin the same cat.

From my rudimentary understanding, resistor forces extra current all the time, and does not account for mfg’s different ratings of minimum switching loads at different voltages. Capacitor provides a burst of electricity for cleaning the contacts at close but doesn’t pull extra amperage all the time.

Here’s a link that may help: en.m.wikipedia.org/wiki/Wetting_current

There are plenty of resources out there to research and draw your own informed decision.

I’m not an electrical engineer. But if I were going to run one (have not yet found this to be necessary with my hypertherm 65 (but the fact that contact oxidation and minimum switching currents are a real thing is filed away for later)) I would likely pick the capacitor. It was far more important in my setup to add a debounce to the arc ok input. Which is now standard at 5mS. I’ve seen others need as much as 10mS. At any rate, your local humidity/temperature/etc may be different.

snowgoer540 wrote: In the diagram that post is referring to, the field power + side is wired directly to the input for arc ok. It was a mistake in the diagram.

As for resistor vs cap, it’s two different ways to skin the same cat.

Thanks! I may leave it out for now and see how things go.

Quick side question. I powered my THCAD 10 from the same 'common' PSU as the Mesa board. Is there anything wrong with that? or does it need to get power from the Mesa board?