GENERATOR-welding

[flINTLOCK]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use. My projected shop is not going to have utility line for electric.

 

[MrJimi]

Unless you know something I don't, I was told many times I can't use a generator for mig welding ?
If it works ? I would recommend a 50 amp out for welding 3/8
I hope others will chime in
Jim

 

[texasjohn]

I have a generator.... 20 amp circuit breaker on 220 volts.

I have a Miller 172 mig welder.

They work together. Never popped the circuit breaker so far. Very slight delay as generator senses the load and kicks into high gear.

I've seen numerous TBN threads on this topic. You can use the search function to find them. The key seems to be to have a generator where the output is greater than the demand of the welder.

Lots of people think it won't work... but it does.

If you already own the welder, get a generator with somewhat greater capability than what the welder will pull. If you haven't purchased a welder yet, consider getting both in one unit... on wheels... all this stuff is HEAVY.

 

[schmism]

Unless you know something I don't, I was told many times I can't use a generator for mig welding ?

they make off the shelf engine driven mig welders, which are nothing more than a engine driven generator (to produce the electricy) and a welder unit to use it in one shell

Miller - Engine-Driven Welders - Bobcat™ 225

as for your application, it depends. 3/8" is some heavy stuff, you cant touch that without a 220v mig. 170+ amps and up would be my guess. That sort of output needs something in the 30amp 220v input.

most generators come with a 20 amp or sometimes a 25 amp plug.

to run that size welder off a genny your looking at something in the 8K watt range id say.

 

[Highbeam]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use. My projected shop is not going to have utility line for electric.

Of course it doesn't matter so much the thickness of steel you want to weld as much as the welder you want to use to do it. To figure out what your welder actually needs either do the math or use a clamp on amp meter and then get a generator with at least that much capacity.

For example, my Lincoln AC 225 arc welder is supposed to also weld 1/2 inch material but the more valuable information is that it welds at about 25 volts (input vlotage is 220) and that the highest output setting is 225 amps. So if I do the math 225 x 25 I see that I need 5625 watts but than I need to be realistic and assume some efficiency losses so throw in 10% and that's only 6188 watts. My generator is capable of 6850 surge watts and 5500 running watts so it is slightly undersized for max welder output but welding at the more typical 90-120 amps leaves me plenty of spare capacity and I can tell you it works well for the field work I bought it for. Portable generators get really expensive after you cross the 6000 watt line.

If your welder is very adequate for 3/8" plate and you plan on doing it a lot, then I would protect that expensive welder with a lot of extra generator capacity. Plus, what about lights and fans? the radio in the corner? If this is a semi-permanent mount then I would honestly look in the 10KW range as a minimum. You'll be spending some money for this genset so you may want to be sure that your needs won't necessitate a larger genset in the future. For just the welder, I am betting that a more typical 6-7000 watt hardware store generator will do it. The mig is just a wire burner after all.

Take a look at Rob's solar power shed project for a good permanent mount genset of a little higher capacity. He has good photos and documentation showing the process. What you're doing is replacing the utility power for an "off-grid" shop so the "off-grid" home projects are a great resource.

If the dollars are getting too high for you then HD sells a gasoline powered 15KW genset for only like 2000$. You'd be up and running that day.

Let us know how this project goes. It always amazes me how people think that the power from a generator is somehow not as good as the power from the wall. Also, a 50 amp plug is standard on almost all welders not because you need 50 amps but so that you can plug into any workstation with any welder.

 

[3RRL]

I will second what Highbeam said. I read a lot of his earlier posts telling of his welding adventures on his rural property. He helped me to get my Lincoln 225 arc welder and it works great in the field. I do all my welding off a Generac 5550 Wheelhouse which has 5550 watts and a surge of 8750. I've never needed to crank the welder up to 225. Most of my welding on thick plates of 1/2" or less is in the 175 to 200 range and that's plenty. I've welded 5/8" thick plates onto my boxblade in the field. The generator provides plenty of juice to run it. I got mine at Home Depot and I think it was under $600 at the time.

 

[Tom_Veatch]

If planning to use MIG machine for up to 3/8" thick steel, how big a generator should you use.

Match the generator to the current draw of your welder. My MM180 asks for a 25 amp circuit. That is about a 6 kva load. My XL225 stick welder, which I'm thinking would be a better choice for 3/8 material, calls for a 50 amp circuit or about 12 kva. Of course, those are at maximum amperage output. Rarely will you use the full output of the welder. You need to check the specs on your welder to find your specific requirements.

I assume you'll be using a 220v welder which probably has a NEMA 6-50 plug. Both of mine do. It's doubtful the generator has a matching receptacle. 220v power from the generator will probably go to a 4 prong outlet (2 hots + neutral + ground) so that both 220 and 110 can be supplied to the load. The NEMA 6-50 is a 3 prong configuration (2 hots + ground) so you'll probably be faced with adapting the welder plug to the generator receptacle.

My generator has a NEMA 14-60 receptacle for which not a single local outlet stocks a matching plug. Cheapest 14-60 plug I could find online was $50 + shipping. Most places wanted between $70 and $90.

 

[Highbeam]

I assume you'll be using a 220v welder which probably has a NEMA 6-50 plug. Both of mine do. It's doubtful the generator has a matching receptacle. 220v power from the generator will probably go to a 4 prong outlet (2 hots + neutral + ground) so that both 220 and 110 can be supplied to the load. The NEMA 6-50 is a 3 prong configuration (2 hots + ground) so you'll probably be faced with adapting the welder plug to the generator receptacle.

My generator has a NEMA 14-60 receptacle for which not a single local outlet stocks a matching plug. Cheapest 14-60 plug I could find online was $50 + shipping. Most places wanted between $70 and $90.

In reference to the plug issue, I made an adapter using 6 feet of heavy cord that converts from the 4 prong twistlok generator plug to the 3 prong standard welder (6-50?) style. The cord was about 1$ a foot and the outlets were about 12$ apiece. Since a three prong 6-50 plug doesn't need the neutral I chose to utilize the ground, plus the 2 hots from the 4 prong twistlok.

Remember that the generator has circuit breakers limiting the output so the adapted wires and plugs need to be rated at least as highly as the generator's outlet.

All of this talk makes me want to go burn some rods. It's been a long winter.

 

[Tom_Veatch]

In reference to the plug issue, I made an adapter using 6 feet of heavy cord that converts from the 4 prong twistlok generator plug to the 3 prong standard welder (6-50?) style. The cord was about 1$ a foot and the outlets were about 12$ apiece. Since a three prong 6-50 plug doesn't need the neutral I chose to utilize the ground, plus the 2 hots from the 4 prong twistlok.

Wish mine could have done that inexpensively. I have two welders and didn't want to change their plugs - especially not at $50+ per pop. Nor did I want to replace the receptacle on the generator and trash the High Dollar cable the feeds the house from the generator.

So, I bought one of the NEMA 14-60 (4 prong, 60 amp, straight prong non-twistloc) plugs from the online vendor and a 6-50 receptacle (3 straight prong, 50 amp) from the local box store (somewhere in the neighborhood of $15) and about a foot off a length of heavy flexible 3 conductor cable from the local weld shop. Like you, I only wired up the two hots and ground in the 4-prong plug.

 

[thingy]

,,,Schimes,said you need a 170 amp welder to weld 3/8 inch steel??!!What would you need to weld 1 inch thick steel than schimes?? A 350 amp machine?? How about inch and a half,a 500 amp,,,,man! Thats not how you weld.3rrl,,you stick weld 1/2 inch with 170-200 amps,,man,you gotta be using a 3/16th rod,,do you ever burn any holes in things?Get any splatter? again,thats not how you weld. You can weld 1/2 inch just fine with 1/8 inch rods at maybe 120-130 amps,,,,,you put more than one pass,,,5/32 would be better at about 150 amps, but you would need a second or third pass even with 5/32,,,again,you don't go about trying to weld everything in one pass.
Yeah,getting a generator,,guess you ain't got one so you might as well get a good sized one,than you have some wiggle room and you got a generator for your house as well. I'd get a generator welder for 2-3,000 and stick weld the stuff,but thats just me,,,,,thingy