# Generator for welder?



## scott63 (Nov 6, 2017)

I have a small Lincoln 100 flux core wire welder that I would like to be able to run off a generator, as well as use the generator for freezer/refrigerator if power fails. The welder is 110v and 20amps, I've been reading and am now more confused than before. It would seem I need a generator that can produce 20amps of power for the 110 voltage output, but that 20 amps need to be 80% of total output since you don't want to run the generator at max output?

So what wattage of a generator do I need for the welder?
Champion/Briggs&Straton/Predator any preferance?
Thanks for clearing this up!


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## exmar (Jun 29, 2015)

Keep it simple, 120V X 30Amps is 3600Watts. There are a lot of 3500W machines out there. The concern about the "lower priced" gensets being run at max is for extended periods. e.g. Power outage, the 3500W machine previously mentioned being run at 3400Watts for hours at a time. Not a welder, but don't think you'll be drawing 20A for hours at a time, even if you did, you'd be running at about 2/3 capacity. I have a 3750W that runs my house, including frig and freezer and other odds and ends which you'll find you want in an extended outage. The next queston you'll have is "do I need an inverter generator?" For what you describe, no. However, I'm sure the "inverter chorus" will chime in shortly.  JMHO.


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## scott63 (Nov 6, 2017)

Thank you, that was exactly the info I was looking for!


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## KRE (Nov 29, 2011)

scott63 said:


> I have a small Lincoln 100 flux core wire welder that I would like to be able to run off a generator, as well as use the generator for freezer/refrigerator if power fails. The welder is 110v and 20amps, I've been reading and am now more confused than before. It would seem I need a generator that can produce 20amps of power for the 110 voltage output, but that 20 amps need to be 80% of total output since you don't want to run the generator at max output?
> 
> So what wattage of a generator do I need for the welder?
> Champion/Briggs&Straton/Predator any preferance?
> Thanks for clearing this up!


Welders have a very low power factor. All single phase gen-sets are rated at unity, an when used on a lagging PF a single phase gensets rating drops like a rock. If it were I, I'D use no less than a 5kw as I don't like burn't winding's. The price between a 3.5 vs a 5kw is pocket change but, replacing do to improperly sizing an burning it up, is very costly.


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## scott63 (Nov 6, 2017)

Thanks for the info, after looking at some 3500/4000 and seeing the price difference to to go up to 5kw I pretty much made up my mind to go with the 5kw. The only bummer is they get heavy going bigger, which sucks for getting in onto a truck to haul around for welding.
Thanks again


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## Handyhiker (Sep 29, 2016)

I have a Lincoln wire feed welder I run from a generator often. I used a Coleman Powermate 3000 watt and had no issues. Now I use a Champion 4000/3500 watt and no issues. Both run the welder fine and are easy enough to move around.


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## Predator (Sep 19, 2017)

I also run my lincoln wire feed welder from my Coleman Powermate.
I have a Powermate 6250 and it does fine with it.

I do "prefer" to run my fridge and electronics with an Inverter generator, but I have run my fridge with the Powermate.
Probably just runs a bit more efficient on an Inverter genset.

I could not get my computer battery backup devices to work with a non-Inverter genset tho. They only seem to dine on clean power.


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## KRE (Nov 29, 2011)

Open the window on the UPS, or readjust the hertz an voltage on the genset an it should work just fine.


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## Predator (Sep 19, 2017)

KRE said:


> Open the window on the UPS, or readjust the hertz an voltage on the genset an it should work just fine.


By Open the Window, are you referring to the voltage peak adjustments?

I have a Hitachi Oscilloscope and the output sine waves of the non-inverter gensets look very different from that from Inverter gensets. The house current sine wave is nearly identical to the Inverter generator sine wave. The non inverter generator's sine wave is much blockier and has sharp spikes.

The Powermate's output frequency of course is tied to the rpm of the engine. It's impossible to get it to run dead set on any set RPM. It varies a little. All generators do that. So from the factory they are adjusted to run at about 59Hz so that under mid load they are around 60Hz. Under full load the Hz can climb to 61 or even 62 Hz.


This illustrates almost to a T what I saw when I tested them both.


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## KRE (Nov 29, 2011)

No rotating field A/C generator has a sine wave output like you posted. That is a modifed sine wave from an inverter. There is a major difference between a modified an true sine wave. A Tektronix 2465 gets me by most of the time, but these are the go to when it gets serious, 
Power Analyzers | Yokogawa Test & Measurement Corporation 

The Textronix shows a lot but can't hold a candle to the Yokogawa. Flukes are good for many things but a 100ms capture time is lacking most of the time.

If you have a rotating field A/C generator an are seeing transient in the waveform w/o load most of the time it's the excitation system that is the issue, that can be corrected with simple caps an filters. If the waveform is clean until the load hits it that could be the load only or the harmonics of the load are in line with the design harmonics of the genset, this can be bad depending. They can be move around somewhat with a little tinkering.


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## Predator (Sep 19, 2017)

I think the illustration is to make the point that the output from an Inverter generator will be better. 

It's been a while since I put the O-scope on the generator, but I'll do it again soon and post the wave form. IIRC, it was very choppy.

That said, my memory is not what it used to be and I also have a number of Inverters. I clearly remember one of them saying Modified Sine Wave but I can't find that one now. Could be I'm remembering the sine wave from one of them.

Can you be more specific about these "simple" caps & filters and where you would install them as I'm sure almost anyone with a non-inverter generator would very much like to do this kind of upgrade.

But wouldn't it be simpler to just use a good quality line filter such as Tripplite offers? Plug this into the generator and then plug electronics into that.

I can't exactly recall, but during hurricane Wilma, I powered my refrigerator with a modified sine wave Inverter (or my Powermate 6250) and it was not happy.
I recall water seeping from the ice maker tray and the temps would get too warm. But that's been years now and I can't recall which was powering it.
I do know for sure it wasnt one of my Inverter generators because I started acquiring those after Wilma (because of that problem)


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## KRE (Nov 29, 2011)

Predator said:


> I think the illustration is to make the point that the output from an Inverter generator will be better.
> 
> It's been a while since I put the O-scope on the generator, but I'll do it again soon and post the wave form. IIRC, it was very choppy.
> 
> ...


Either a square or modified sine wave should never be used on a inductive load (motors/transformers ect) as they will heat same to the point of failure over time.
Tripplte is just selling you 2 dollars worth of caps an filters with a MOV or two thrown in installed in a box with a few duplex outlets, the main safety device in them are the MOV's which are pocket change in reality. 

Load up an inverter genset then put the O scope on it, it will be different than w/o load. 
A quality rotating field genset will have a better sine wave with or w/o load than most all inverters doing same. The advantage of the inverter is the varying engine speed difference, while maintaining 60hz .


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## KRE (Nov 29, 2011)

here is a link as to what a MOV is/does
http://www.electronics-tutorials.ws/resistor/varistor.html


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## KRE (Nov 29, 2011)

Predator said:


> Can you be more specific about these "simple" caps & filters and where you would install them as I'm sure almost anyone with a non-inverter generator would very much like to do this kind of upgrade.


Missed that sorry, most all rope start gensets have a closed loop excitation system, an when electronic trash is on the output that same trash gets induced into the excitation as well. The clean up has to happen at excitation, clean in clean out. Trash in trash out.


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## Oscar (Nov 11, 2017)

exmar said:


> Keep it simple, 120V X 30Amps is 3600Watts. There are a lot of 3500W machines out there. The concern about the "lower priced" gensets being run at max is for extended periods. e.g. Power outage, the 3500W machine previously mentioned being run at 3400Watts for hours at a time. Not a welder, but don't think you'll be drawing 20A for hours at a time, even if you did, you'd be running at about 2/3 capacity. I have a 3750W that runs my house, including frig and freezer and other odds and ends which you'll find you want in an extended outage. The next queston you'll have is "do I need an inverter generator?" For what you describe, no. However, I'm sure the "inverter chorus" will chime in shortly.  JMHO.


I agree with ~3500W. The initial current spike from the instant the arc is struck can consume extra power, so the 30A peak draw is a good estimate to keep both the welder and the generator happy. I use a Troy-Bilt 7000X with both my Millermatic 211 and my HTP Invertig 221 welders, and it works great so far.


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## Oscar (Nov 11, 2017)

Darn can't edit my post, lol. Forgot to mention that even though both my welders are inverter-based, my generator is not but reportedly has very low THD (<6%) from the research/info I had done/found. I also plan to wire it up to the house for emergencies but haven't actually gotten around to it, since we have very few power outages. But I know that I will regret not doing so the next power outage we have, lol.


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## Predator (Sep 19, 2017)

Oscar said:


> Darn can't edit my post, lol. Forgot to mention that even though both my welders are inverter-based, my generator is not but reportedly has very low THD (<6%) from the research/info I had done/found. I also plan to wire it up to the house for emergencies but haven't actually gotten around to it, since we have very few power outages. But I know that I will regret not doing so the next power outage we have, lol.


IIRC, my 6250 works pretty hard to run my arc welder....but getting old and time are not kind to sharp memories 
Winter is the perfect time to get a Round Tuit


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## Oscar (Nov 11, 2017)

Predator said:


> IIRC, my 6250 works pretty hard to run my arc welder....but getting old and time are not kind to sharp memories
> Winter is the perfect time to get a Round Tuit


If by "arc welder" you mean SMAW aka: stick welder (technically most forms are welding are arc welding since they use an electric arc), then yea it is very hard on a welder due to the high current demand when the arc is struck PLUS the fact that many stick welders have a hot-start circuit that bumps the amperage up beyond what it is set to by the user to help establish the arc, it can be really taxing on small/medium generators.

How's that HF 3500W inverter generator? Seems like a pretty good unit for the money.


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## Predator (Sep 19, 2017)

Oscar said:


> If by "arc welder" you mean SMAW aka: stick welder (technically most forms are welding are arc welding since they use an electric arc), then yea it is very hard on a welder due to the high current demand when the arc is struck PLUS the fact that many stick welders have a hot-start circuit that bumps the amperage up beyond what it is set to by the user to help establish the arc, it can be really taxing on small/medium generators.
> 
> How's that HF 3500W inverter generator? Seems like a pretty good unit for the money.


FLAT OUT LOVE IT !!!!!!

No kidding. It's quieter than my Honda eu2000i while putting out almost twice the power.
The LED console shows me hours total, todays runtime plus a lot more.....
Really, when it's putting out 2600watts, it's like it's not even breaking a sweat. Like it's doing it 
while reading a book.

VERY WELL thought out unit from the Oil drain set up to the redundant pull starter (it is electric start too!)

Might buy another. It's that good.
It's just one of the coolest generators I've ever owned.


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