Pilot Arc on 200PI

[Uncle Ed]

Hi guys.

I have been using the 200pi off and on and have been pretty happy with it. One sore spot was having to be right on the edge of a piece before I can start a clean cut.

I was watching Deconstructed on TV and the plasma cutter they used would throw a flame in open air. Isn't the 200pi supposed to do that, also? I have only used regular plasma cutters and really didn't pay attention when using the 200. I would just cut the metal an move on. Am I missing a feature?

Unfortunately, the welder is at work and I only seem to remember this stuff when I am at home, so I cannot fire it up to refresh my poor memory. I do not recall being able to start the plasma until I am in position.

If it's supposed to be able to start an arc in air, what should I look for as the culprit? I will try out any suggestions when I go in to work Monday afternoon.

Ed

[Gadget]

I did some testing today for just that. The pilot arc stops when the distance to the metal gets too big. The pilot arc will start in the air but once the current is transfered to the metal being cut any excessive gap will cause the arc to stop and you will have to wait until the air flow has stopped.
I connected the pilot arc wire directly to ground today and was able to air start, begin cutting, move the arc completely off the metal and resume cutting without arc stoppage. I tried this a number of times and the arc was constant for each test. I don't know if this is an approved method but I don't see how it could harm the unit. The only risk is maintaining too great a distance and carrying the arc over the smaller pilot wire for too long causing a heat buildup in the wire. If you are careful to maintain the correct tip distance things should work ok.

[Uncle Ed]

Okay, lemme see if I have this right.

Pull the trigger and it should fire up. Bring it to the metal to cut and the circuitry switches over to the main workpiece ground and the cut is made. The plasma dies when pulled away from the metal until the circuitry allows me to start another arc.

I remember noticing that I cannot restart an arc unless I am on the metal so I have to be right on target. If I am over the gap of the previous cut or where I left off, the arc doesn't start. If I am over new metal I get a keyhole in my otherwise clean cut. I cannot start the arc and feather into my previous cut line so it appears that Pilot Arc is not working on my unit.

Ed

---------- Post added at 09:29 PM ---------- Previous post was at 09:19 PM ----------

Did you connect the Pilot Arc wire to chassis ground or electrode (ground clamp) ground?

I am gonna take a laptop to work and post what I find and any other nuisances I find.

One of the issues is that using the unit in my shop at work takes out the network switch and shop computer until they are unplugged for awhile and reset. I didn't notice THAT until I was called to verify my hours. The time clock for that section of the building runs through the shop switch and the clock could not send off the days punches until the switch gets reset.

Ed

[Gadget]

I connected the pilot arc wire to the ground clamp instead of the pilot lug.
My explanation on how the pilot arc works is based only on my experience with the unit. You should probably get verification of that from Longevity support. In any case, you should be able to restart over the metal or in air once the unit air has cycled off. I can do that with mine with the pilot arc wire connected to the proper lug.
I suggest you create a shield around the switch and if possible the computer. Aluminum window screen should shield them enough to prevent the outages. I use that on my CNC table.

[Hamstn]

I saw some cutters had a grounding lug on the back to help the interference with computers. Does this help to ground the machine? I thought it was for the HF start though and not the pilot arc. Or is it the actual arc that is causing the interference?


I ran into this with my Ham radios and PC's. One way to lessen the interference was good grounding and shielding the PC with screen or copper.

[Gadget]

by grounding the lug you are grounding the case. This may help some but I would still shield the other equipment.

[inot]

I ran into this with my Ham radios and PC's. One way to lessen the interference was good grounding and shielding the PC with screen or copper.

I would start with running heavy wire from the ground lug on the machine's case to a good ground. You can also ground the cases for the switch and computer as well.

The computer and the switch should be shielded by the cases they are housed in, but if a screen fixes the problem the cases obviously aren't doing the job. If RF is getting in after the case is shielded properly it is probably being carried on the cables connected to the system.

At home I use Tripp Lite Isobar ultra series suppressors on the AC lines to my radios and nearby computer. This will knock down the RFI/EMI that is carried on wires in the house. I also have snap-on ferrite cores clipped on any cables that did not come with ferrite filters installed. I do not have ferrite filters on the ethernet cables, but you can try that as well.

I am curious to see what the solution will be in this case. At work we have wire EDM running within a few feet of standard desktop PCs with no special filtering or precautions on the computer/network side. We have not seem any problems, but I would not be surprised if do encounter a similar issue someday.

[Uncle Ed]

Thanks for the arc info, Dan. Things are much easier when you know the theory of operation.

The computer is shielded so I bet it's getting in through the many cords. Gonna have to find some clamp-on ferrites cheap. The switch has a plastic housing and I may just ask (I can dream...) the company to get a better one.

[Uncle Ed]

Well I'll be a...

Got into work, pulled the trigger and it fired right up.

This Multiple Personality Disorder I have is really messing with me.

Which one was cutting?
Which one posted the complaint?
Which one gets the paychecks and hides them from the rest of us??

Arrghh

[idahoaj1]

lol..
no offense, but that right thar is funny!
mostly cause i've made the same mistake, and felt like a monkeys arse when a buddy pointed out what the pilot arc is.