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Author Topic: HF Inverter TIG welder on an ST5?  (Read 4040 times)

vtmetro

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HF Inverter TIG welder on an ST5?
« on: August 28, 2015, 04:35:10 PM »
I'm just wondering if anyone here has had experience running a inverter TIG welder off of the 240V output of a 6/1 with an ST5 gen head (mine has an AVR)?

I ask because I have somewhat successfully run a Harbor Freight Inverter TIG welder from a 4KW Generac w/3600 rpm Briggs engine.

When I say somewhat, I mean it welded fine at a reasonably low setting (110 amps) doing just a stick job, but I was a bit nervous and turned th e welder off between short welds. Everything went well, and then I got more confident and didn't switch off. After about 5 minutes of very intermittent and short welds -- mostly positioning things, I saw and smelled some smoke coming out of the welder, and shut it down, thinking the worst.

I opened up the case and saw no blackened traces or wires, nothing obvious at all. Finally noticed what looked like maybe a huge air cooled wound power resistor or coil (not sure what it is) had a little of the varnish looking slightly different than another one, and it seemed in the position where the smoke came from, and I felt a little residual heat in the chassis there, so I guessed this might have been the cause.

I reconnected the welder to mains 240, and it started up fine and welded.

So, I'm a little hesitant to run it off of the Metro now -- although that's supposed to be one of the reasons I got it. I hate to experiment, where you find out the answer to a question by burning out a $500 welder, so I really wonder if anyone else has had experience with a welder on a Listeroid/ST5.

In trying to figure out what happened, I did try it again very briefly on the Generac. It also works there still, but I switched it off before heat could build up in that reisistor/whatever. Everything seemed cool afterward.

In reading more about 240v operation here on the Listeroid, I've started to wonder if what happened on the Generac had anything to do with voltage regulation -- maybe on one leg only?

The Generac has a 4 prong receptacle for output of 240 and split 120. The welder has a 3 prong plug and was hooked to a receptacle fed from the generator outlet and was wired with equipment ground to the ground prong, and black and red to the two hot lugs. White neutral was not connected.

I don't know how the Generac is regulated -- whether the 240 is regulated, or whether only one leg of 120 is regulated. Is it possible that I had the floating neutral problem, or that I miswired the plug and outlet, and the welder got too high or too low a voltage?

Or, is this possibly a 240V generator waveform or noise problem that the inverter welder can't cope with? And should I expect the same or worse with the Metro/6-1/ST5 head?

Thanks for your help.


Tom

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Re: HF Inverter TIG welder on an ST5?
« Reply #1 on: August 28, 2015, 05:36:48 PM »
Don't have a tig welder here, but my Hobart Handler 180 120v runs just fine off of the ST5. However I am running a balancing transformer. Are you going off-grid or just setting up a "portable" welding rig? The reason I ask is that with the proper inverter/battery/genny setup you can handle some pretty huge loads.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

vtmetro

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Re: HF Inverter TIG welder on an ST5?
« Reply #2 on: August 28, 2015, 09:02:00 PM »
Hi Tom, no, not going off grid.

I'd really like it if I could do occasional welding with the listeroid -- that's the only time I need 240V.

Otherwise I'd like it to provide heat and electricity (110V) in winter for a very tiny shop that it is adjacent to. Maybe 4 hrs/day, 3-4 days a week, winter only.

And a third use would be to power some of the house circuits in a power outtage (also only 110V). Maybe 4 times a year.

I might weld a few times a month, max. Repairs or building a project.

I also have an old clunker tombstone Lincoln buzz-box stick welder, and I could probably bring that one up here from my other shop. And trade the TIG back down there.

I Imagine the heavy tombstone is less sensitive than the inverter TIG welder -- being pre-digital everything. But the TIG is nice and small and I can move it around easily. I don't think the buzz box is as efficient, so I do wonder if the Metro can power it.

I think the TIG is only putting out 10 to 15V max through the stinger, so 100 amps is less than 1.5 kW. And efficiency high.

I think the buzzbox is probably quite a bit higher voltage at the stinger, so 100 amps is a lot more watts, and probably not too efficient to get there, either.

I'm not in a position to buy any more gear at present, so I'm hoping to work out something with the Metro, with what I have. If the TIG will run without smoking on the Metro, that would be ideal.

Wish I knew for sure what the reason was the other day that it didn't like the Generac. The overheating happened while it was not welding, just on. And the generator was loading down, so it was drawing for some reason.

« Last Edit: August 28, 2015, 09:16:20 PM by vtmetro »

Thob

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Re: HF Inverter TIG welder on an ST5?
« Reply #3 on: August 29, 2015, 07:42:34 PM »
Sounds to me like the problem is in the HF tig unit.  Most units have a big wire wound choke (inductor) on the output lead, and the Chinese units are known for using way too small of wire there.  It may have overheated while welding, but continued to smoke for some time afterwards.

Also, if an inverter welder is drawing a significant load when not welding, something is definitely wrong with it.

Most (all?) inverter welders rectify the incoming AC into a set of filter capacitors.  They *SHOULD* be very tolerant of poor quality AC.  Only the tip of the AC waveform is actually being used anyway.

Maybe a search for HF TIG welder problems?  Should get lots of hits ;D
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mike90045

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Re: HF Inverter TIG welder on an ST5?
« Reply #4 on: August 30, 2015, 07:23:21 AM »
HF - isn't that the company that makes stuff that looks like tools ?

Don't they have a warranty for their gear. 1 year ?   Hook it up and run it.  ST5 should be fine to power a welder, and if it does smoke,
it's quite likely the welder was bad anyway.  Don't give them an out, saying you ran it off a generator.

Everything at my place works fine off the ST5, except the garage door opener, the safety circuits interpret the power pulse as an obstruction and reverses the door to OPEN.

vtmetro

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Re: HF Inverter TIG welder on an ST5?
« Reply #5 on: August 30, 2015, 05:15:59 PM »
Thob, thanks kindly. And I think you hit the nail on the head. It almost certainly an output choke, and I think it probably did continue to smoke the coating from residual heat after I turned it off.

Mike, thanks. It's more like 4 years old, just used very little, so I'm going to have to solve the problems myself.

Remember, it was the loud Briggs and Stratton driven Generac, too. I'm not saying the ST5 would cause the problem -- just asking if others have run a similar or the same welder off an ST5.

I did reconfigure the ST5 for 240, and did give the TIG welder a short try on it yesterday -- welded some half inch rebar into a Tee, and didn't notice any problem. But I also didn't leave it on for more than a minute that it took to put on the helmet and position things and lay down a couple of welds. It sounds like it should work okay from other's experience so far if the welder itself is okay.

I'll do a search online for choke problems for the HF welder. That welder did get very good reviews when I bought it ........from a whole lot of people on different forums, but of course this one could be an exception.

I think I'll hook it up to mains again and leave it on for a good amount of time to see if it does the same thing. If so, I know it's a welder problem. If not, it was a Generac problem. And I'll need to test to find out if it will be a ST5 problem.

I still wonder if my 240 hookup to the Generac might have had something to do with it -- somehow messing up its voltage regulation. like I said, it was a 4 prong outlet at the generator, fed into a 3 prong outlet for the welder.

I brought out the two 240 hot lines (red and black) and the equipment ground (bare copper) to the welder's factory 3 prong plug. The neutral (white) was left unconnected.

Maybe that messed up the voltage regulator (if there is one) in the Generac. It's a 4000XL model generator


UPDATE:

I just tested the welder on 240V mains AC and it works perfectly there. I spent a half hour welding with it. No smoke. Case fan exhaust was cool. I know that if I put it back on the Generac, even without welding, there would be smoke in about 5 minutes. My conclusion is the welder itself is not defective. Something about the combination is the problem. I wish I knew what that was.

« Last Edit: August 30, 2015, 07:10:12 PM by vtmetro »