Help choosing 240v generator for MIG welder?

   / Help choosing 240v generator for MIG welder? #11  
Sodo, many economy generators produce a modified square wave instead of a sine wave. It's designed to appear "sine-ish", but the tops of the wave are flattened and it "falls" through the zero point instead of the curved rise of a sine wave (forget what it is called now). Most of these generators are actually alternators, and they produce a dirty wave, and on 240V, the phase angle is not properly aligned. (that is about as technical as I get or it makes my head hurt). Inverter generators can produce a clean sine wave, but not all do. A clean sine wave is generally regard as 10% or less total harmonic distortion. Northern Tool claims 5% on that unit...which is better than the average household current in some areas of the country. Any way, dirty sine waves and modified square waves tears up electronic equipment. Just because a unit puts OUT a square wave or DC wave doesn't mean it wants a square wave input. Inverters and transformer rectifiers alike produce a square wave by chopping the tops/bottoms off of an AC sine wave to produce a somewhat squiggly DC wave.

If you would not plug your computer tower into it, you don't need to plug your inverter welder into it. A transformer may not care as much although the arc quality may not be as good...basically garbage in/garbage out...although I am sure it could eventually damage one as well if it were bad enough.
 
   / Help choosing 240v generator for MIG welder?
  • Thread Starter
#12  
Mark, my understanding of generators & electrical power is rudimentary but I understand waveforms and what you wrote. Thanks for the time.

For generator sales,--------> more Watts = more $$$
Consequently generator producers want the biggest wattage number they can get, which could be dirty output. (just an assumption)

Ooops just called MillerWelds and asked a Tech. (tech suppt 1-866-931-9733)
The tech said any generator of reasonable quality should work fine.
The MultiMatic 200 does not care much about the quality of the input power. It converts everything it gets to DC, then inverts it to the power configuration that it wants (to weld with).

But for forum completeness, note that I tried to type the statements (my quote above) exactly as the Miller tech told me but it might be worth confirming. I called again today, but no answer (Saturday).
 
   / Help choosing 240v generator for MIG welder? #13  
It has to do with HOW the power is generated. You will pay double nearly for a clean power generator. Take a well known company like Generac. MOST of their units like the GP are not clean powered. Call them and they will tell you so...and probably will tell you (if prompted) not to use it on any electronics. Resistive loads like lights and some motors are fine. I would rely upon the generator supplier for the information, as they are the ones likely to get left holding the bag if something malfunctions on their genset.
Only their X series, which is more expensive, or the iX inverter based small gensets which start with 3 phase power and clean and convert it from there(which is the same basic generator Everlast sells IIRC, ) are designated as clean power.
 
   / Help choosing 240v generator for MIG welder? #14  
Been quite a few years since my work required the use of a scope, but this discussion is getting me curious -

I was always under the impression that ANY genny that produced AC power by means of a constant speed rotary AC generator, produced a SINE wave - If I get time (Trying to make space for a half-ton milling machine that's due Monday, and a left hand with 3 fingers temporarily out of commission) I'll drag out my scope and see if it even still works, and if it does maybe I can get a few pix of the waveform on my genny.

btw, the "modified sine wave" is usually just a square wave with a "slowed down" rise and fall time, done in lower cost UPS's and such because it's cheaper to build than a true sine wave generator (if you're doing it with electronics instead of rotary motion, that is) -

Mark, the term for that is "trapezoidal wave",named for the fact that each half-cycle looks like a trapezoid.

The reason for a trapezoidal wave (in ELECTRONICALLY generated power), besides lower cost to manufacture, is that a square wave contains essentially ALL ODD HARMONICS of the frequency being generated, which is DEFINITELY not good for the power transformers in the majority of devices. Among other things, it generates more HEAT in the transformer.

The trapezoidal wave, due to its slower rise/fall time, greatly reduces those harmonics. This means that a trapezoidal wave is BETTER for a transformer, but not necessarily good ENOUGH. In order for a transformer to handle non-sine power it needs to be bigger/heavier/more expensive. Not generally the direction most manufacturers wanna go...

Harmonic distortion, in reference to a sine wave, means ANYTHING that puts ANY KIND of "bumps" in an otherwise perfectly drawn sine curve. The more of this there is in a power input, the more expensive the powered device needs to be. Again, not a good business choice.

Hope this didn't get too far afield, just trying to clarify a few points... Steve
 
   / Help choosing 240v generator for MIG welder?
  • Thread Starter
#15  
Steve that was more along the lines of my understanding. But this is farther than I've ever investigated generators in the past.

Category 5 Electric Start Generator — 9375 Watts, Wireless Remote Control, EPA and CARB-Compliant, Model# 41535 | Portable Generators| Northern Tool + Equipment $949 + $193 ship = $1142

This "Category5" brand is a "Champion". Any thoughts on the "Champion" brand?

If the generator was nearby, outside a metal building, can a wireless remote operate the generator thru sheet metal building walls? Or do I have to stick the FOB outside to remote activate? I suppose it would be similar to locking a car with the FOB (which I've never tried), what conditions does this work?
 
   / Help choosing 240v generator for MIG welder? #16  
Been quite a few years since my work required the use of a scope, but this discussion is getting me curious -

I was always under the impression that ANY genny that produced AC power by means of a constant speed rotary AC generator, produced a SINE wave - If I get time (Trying to make space for a half-ton milling machine that's due Monday, and a left hand with 3 fingers temporarily out of commission) I'll drag out my scope and see if it even still works, and if it does maybe I can get a few pix of the waveform on my genny.

btw, the "modified sine wave" is usually just a square wave with a "slowed down" rise and fall time, done in lower cost UPS's and such because it's cheaper to build than a true sine wave generator (if you're doing it with electronics instead of rotary motion, that is) -

Mark, the term for that is "trapezoidal wave",named for the fact that each half-cycle looks like a trapezoid.

The reason for a trapezoidal wave (in ELECTRONICALLY generated power), besides lower cost to manufacture, is that a square wave contains essentially ALL ODD HARMONICS of the frequency being generated, which is DEFINITELY not good for the power transformers in the majority of devices. Among other things, it generates more HEAT in the transformer.

The trapezoidal wave, due to its slower rise/fall time, greatly reduces those harmonics. This means that a trapezoidal wave is BETTER for a transformer, but not necessarily good ENOUGH. In order for a transformer to handle non-sine power it needs to be bigger/heavier/more expensive. Not generally the direction most manufacturers wanna go...

Harmonic distortion, in reference to a sine wave, means ANYTHING that puts ANY KIND of "bumps" in an otherwise perfectly drawn sine curve. The more of this there is in a power input, the more expensive the powered device needs to be. Again, not a good business choice.

Hope this didn't get too far afield, just trying to clarify a few points... Steve
yes good explanation... thanks and yes would be interesting to see what your scope says... what kind of generator do you have? I have a Honda EU3000iS and am told it has good sine wave output but I have not had the need to run sensitive electronics on it but have wondered if it would cause havoc.
 
   / Help choosing 240v generator for MIG welder?
  • Thread Starter
#17  
No worries on the Honda inverter, not even a remote concern, it could be cleaner than your house power.
 
   / Help choosing 240v generator for MIG welder? #18  
My genny is a "Northstar Systems", powered by a Honda GX390 - electric start, except when it's sat awhile (maybe wimpy battery, it hasn't reached the top of my "G.A.S." list, 'cause the Honda starts first pull even after sitting for a year.) No inverter or remote, just the basics. It was $899 @ Costco about 3 years ago.

Sodo, remotes are next to impossible to predict - and as you know, metal walls don't help. You'll most likely have to try it in your situation. The only clue I got from your link was one customer saying,"starts from a long distance away." This kind of comment, to me, is worse than none at all - Is this customer a SLUG that can somehow talk and type (27 INCHES would be a long distance) - is he an IRON MAN competitor (couple MILES is fairly close) or something in between? Sheesh...:confused:

Having been in tech/scientific fields my entire life, I'm probably too picky wanting things actually QUANTIFIED ("The remote worked line of sight to 37 feet, but with a metal building wall in between, it quit responding at just over 9 feet", or something similar, might have been helpful...

Yeah, I know, picky picky picky - I'm just in a foul mood when I do some dumb-azz stunt that cost me a few weeks of restricted activity to heal :thumbdown: - OK, back to the shop to "putter" -

Oh, here's a random neuron fizzle - if your remote doesn't wanna make it thru the metal wall, AND you're OK with replacing a small section of wall with wood siding, AND that genny WILL start from far enough away thru a piece of plywood, that MIGHT be a possible "plan D"...
 
   / Help choosing 240v generator for MIG welder? #19  
Oh, you may wanna download the manual (your link) and search it on the word "remote" - read it carefully before you place your order...
 
   / Help choosing 240v generator for MIG welder?
  • Thread Starter
#20  
Oh, here's a random neuron fizzle - if your remote doesn't wanna make it thru the metal wall, AND you're OK with replacing a small section of wall with wood siding, AND that genny WILL start from far enough away thru a piece of plywood, that MIGHT be a possible "plan D"...

If you're willing to tax more neurons. Bukit if you've been coming up short lately don't burn any up on my account!:D But wondering what size hole in the metal wall will it go thru if I hold the FOB right at the hole? Do you know the wavelength (of the frequency used by that type of remote)?
 
 
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