Driving a welder with an ST5

[veggie]

Has anyone driven an arc welder with an ST5 ?
I'm trying to determine what size of a welder I can drive with the 240V outlet.
Would the welder be considered an inductive or a resistive load ?
Do welders have an amperage spike when an arc is struck similar to an electric motor starting?

PS: My ST5 is driven by a 6/1 with a theoretical max. output of 3kw (I haven't tested the limits yet)

cheers,
veggie

[TimSR2]

I have a lincoln AC 250A buzzbox. It blew the 30 amp breakers in my shop repeatedly at 120 amps setting. After changing them to 40 amp I'm OK up to 135 ( highest I have used so far) . Welders need a lot of juice .

[vdubnut62]

Ditto on the Craftsman buzzbox I have, except I went to 50 amp breakers. I used 50's just because I had them lying around,
not because I thought I  needed them.
Ron

[Crofter]

I have an old lincoln 250 ac dc and I believe it is fused 75 amp, but I can run it with my st5 up to near 150 amps. The big amp spike is starting the arc or especially when you stick a rod to the metal. Merely flipping the switch on with no load on the welder doesnt even seem to register but when you strike an arc the 10-1 snorts a bit.

Arc characteristics seemed ok but it was just a short test on a scrap plate.

[veggie]

Thanks,

From what I read above, a 3kw ST5 would not be able to properly drive a stick welder. 
I was hoping to be able to weld up to 3/8 material with a small arc welder.
There are some MIG welders which can run on lower voltage 120v, 20 amp outlets.
From what I understand, 3/8" plate is too much for a  MIG welder.

veggie

[vdubnut62]

Yep I have one of the low end 110 volt migs, the limit is 1/4 inch stuff. Of course I suppose you could do a couple passes.

Ron

[vdubnut62]

Definitely,  in a prior occupation I ran a mig that burned 1/16th wire on 440 3 phase, that beast would weld just about anything.

Ron.

[mobile_bob]

one of the biggest surprises i have found in a small 120 volt wire feed is the hobart 120 mig

running .030 E70-06 wire and co2 that little bastard will weld like a much larger welder

i have used many of the small lincolns and the harbor freight types all of which i was really
disgusted with

i bought the little hobart with two blown diodes for 100 bucks iirc from a guy on craigslist
replaced them with oem diodes at 36 bucks a pair and put it to work with .023" wire
it did ok, but was really more on a par with the lincolns

when i changed to .030 and co2 it was like kicking it up 20amps and into the realm of a useful
welder.

if your 6/1 with st5 can put out 20amps at 120 volts you could do much worse than a used hobart 120mig

just wish i had a decent 50amp 240 volt supply, i would move in my trusty linde 225 and there is about nothing
i would ever do that it isn't up to welding, right up to spray arc.

but sadly it takes a bit more than a 6/1 can put out even on nitrous



bob g

[TimSR2]

Just stick with the 7018's and a good buzzbox and a little rod heater. KISS principle. We are not all going to be high end ticketed welders. Just messing around and want to weld up some channel iron once in a while......

Tim

[mobile_bob]

good point and probably safer for the beginner than a mig is just using a stick welder
although you might wanna work with 6011 which will give a very sound weld, albeit hard to chip between passes

bob g

[TimSR2]

7018, store em hot,  dig em  in deep  and pour on the heat. love it.

T

[mobile_bob]

thats just the problem, you got a limited amount of heat with a 6/1 and st5

bob g

[Crofter]

My 10-1 running at 900 rpm drives enough out of an ST5 to run a really hot 3/32 7018  so might be a bit iffy with a 6-1, but should run a 3/32 6011 with no problem. The flywheels will carry you through the arc starting time without problem and the continuous output should hold the running arc current without too much sweat.

[veggie]

My 10-1 running at 900 rpm drives enough out of an ST5 to run a really hot 3/32 7018  so might be a bit iffy with a 6-1, but should run a 3/32 6011 with no problem. The flywheels will carry you through the arc starting time without problem and the continuous output should hold the running arc current without too much sweat.

Thanks Crofter,
I picked up a small 120 Volt TIG machine. Can do 1/4" and 3/8" plate if doing 2 passes.
For making brackets and small tacking jobs it should be ideal.
I will report back after A] I learn how to use the darn thing  , and B] Do a few good test welds.
Fortunately I have the help of the welders at work for advise.

This raises another question regarding 120 volt welders.
How concerned should I be about the other (unused) leg of my 120 volt supply from the ST5  

veggie

[bschwartz]

If you want it hot, I'd wire the two legs together.  Until we figure out the BS ST mod, It will be VERY unhappy about pulling that kind of load on only one side.