Thanks in advance.I was wondering if anyone could provide some insight on this. I don't really have any need to do this, I'm just curious. My google-fu is returning a mixed bag of answers. I've heard "it'll be alright" to "it'll melt your welder". I understand generators create very "dirty" power and I could see that being an issue for an inverter. However, my knowledge of generators is somewhat limited and I'm not about to risk my welder to an experiment. Thanks in advance.
Thanks in advance.
noddybrian
- noddybrian
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Well this jubject is a minefield & requires some understanding of a bunch of electical B.S. - but I'll give my experience - others will have their own opinion.
Most manufacture's will state if the model is " generator safe " or not - if unstated ask them - that said , even if it is you can still damage the generator & / or inverter if unlucky or the two are not matched - I have a " generator safe" model from Butters which simply turns itself off when connected to virtually any generator ! if parameters of line voltage / frequency are even fractionally out.
Assuming your going ahead anyway check the plate on the set & look for a " total absorbed power" rating or take maximum current rating - multiply by line voltage then divide by power factor to find out the maximum wattage the set will need - as you never want the generator running at it's maximum rating ( which is usually overstated based on a short duty cycle rather than continuous rating ) now mutliply this by 1.5 - this is how much wattage of generator you need ( it will also be way bigger than you thought & your " mate " will have used one half that size - " worked great " - yea ! )
Now you know how big a generator you need they fall into several groups of how good their output is - a diesel powered set will usually be better as the engine revs are more stable due to more accurate govenor over a gas model - now here is the real sticking point - unless you have an oscilloscope to look at the sine wave it's pot luck how good any particular set will be but the smaller sets will fall into 3 groups.
1- inductive - will have a large capacitor mounted somewhere on the frame - has no brushes on the rotor but will have 2 large diodes somewhere on it - NEVER NEVER use this type - it produce attrocious output with bad voltage control & a double spike in the sine wave to the point on some of being a virtual double on frequency - suitable only for resistive loads such as small brushed power tools & lighting - used on site.
2- old school regenerative uses residual magnetism to create small output into stator - this is fed through transfomer & diode pack to create DC to excite rotor fed via brushes - if set up well this is stable though voltage control is not great across total output range - ususally set by slip rings on ballast resistor - I have an old Stamford set on a 2cylinder Lister of this type & have welded off it for years without problem - it helps to have a set a fair bit bigger than necessary because of voltage fluctuations.
3 - AVR is very similar except the dc excitor voltage is fed from an electronic source that attempts to maintain output voltage within a very close tollerance - this is the recommended type - but they are themselves less tolerant of back EMF from inductive / reactive loads - some seem better than others & like most electronic things they are improving over the years.
Bottom line is check generator is of adequate size - check engine is running at correct RPM for frequency while under load - if possible check sine wave of output & you should be OK.
(disclaimer - do not call me when smoke is coming out of your brand new Dynasty & Harbour Freight / Walmart / Home Depot import generator.
Most manufacture's will state if the model is " generator safe " or not - if unstated ask them - that said , even if it is you can still damage the generator & / or inverter if unlucky or the two are not matched - I have a " generator safe" model from Butters which simply turns itself off when connected to virtually any generator ! if parameters of line voltage / frequency are even fractionally out.
Assuming your going ahead anyway check the plate on the set & look for a " total absorbed power" rating or take maximum current rating - multiply by line voltage then divide by power factor to find out the maximum wattage the set will need - as you never want the generator running at it's maximum rating ( which is usually overstated based on a short duty cycle rather than continuous rating ) now mutliply this by 1.5 - this is how much wattage of generator you need ( it will also be way bigger than you thought & your " mate " will have used one half that size - " worked great " - yea ! )
Now you know how big a generator you need they fall into several groups of how good their output is - a diesel powered set will usually be better as the engine revs are more stable due to more accurate govenor over a gas model - now here is the real sticking point - unless you have an oscilloscope to look at the sine wave it's pot luck how good any particular set will be but the smaller sets will fall into 3 groups.
1- inductive - will have a large capacitor mounted somewhere on the frame - has no brushes on the rotor but will have 2 large diodes somewhere on it - NEVER NEVER use this type - it produce attrocious output with bad voltage control & a double spike in the sine wave to the point on some of being a virtual double on frequency - suitable only for resistive loads such as small brushed power tools & lighting - used on site.
2- old school regenerative uses residual magnetism to create small output into stator - this is fed through transfomer & diode pack to create DC to excite rotor fed via brushes - if set up well this is stable though voltage control is not great across total output range - ususally set by slip rings on ballast resistor - I have an old Stamford set on a 2cylinder Lister of this type & have welded off it for years without problem - it helps to have a set a fair bit bigger than necessary because of voltage fluctuations.
3 - AVR is very similar except the dc excitor voltage is fed from an electronic source that attempts to maintain output voltage within a very close tollerance - this is the recommended type - but they are themselves less tolerant of back EMF from inductive / reactive loads - some seem better than others & like most electronic things they are improving over the years.
Bottom line is check generator is of adequate size - check engine is running at correct RPM for frequency while under load - if possible check sine wave of output & you should be OK.
(disclaimer - do not call me when smoke is coming out of your brand new Dynasty & Harbour Freight / Walmart / Home Depot import generator.
- Otto Nobedder
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A rule of thumb, which I'll relate to Brian's excellent analysis, is this:
The generator's "working" capacity (not peak), should be at least four times the inverter's absolute peak load.
Why? Because the smoothing circuit, and the frequency control circuit along with the governer, will be far more consistent and reliable when operated at 25% capacity or below. Sudden loads, such as sticking the tungsten (or the rod in SMAW mode) will have minimal effect, and minimal surge as the generator tries to compensate.
Opinions may vary on this.
The short form on my opinion is this... If your generator has 4X the capacity your welder requires, you spent some coin on it... It didn't come from harbor freight (failure to use capital letters intentional!), and likely has everything you need to keep a clean sine wave at 60 Hz.
Steve S
The generator's "working" capacity (not peak), should be at least four times the inverter's absolute peak load.
Why? Because the smoothing circuit, and the frequency control circuit along with the governer, will be far more consistent and reliable when operated at 25% capacity or below. Sudden loads, such as sticking the tungsten (or the rod in SMAW mode) will have minimal effect, and minimal surge as the generator tries to compensate.
Opinions may vary on this.
The short form on my opinion is this... If your generator has 4X the capacity your welder requires, you spent some coin on it... It didn't come from harbor freight (failure to use capital letters intentional!), and likely has everything you need to keep a clean sine wave at 60 Hz.
Steve S
I recently bought an Everlast PowerArc 160 for TIG. Mobile power is a Miller Trailblazer 301G. Before I bought they inverter I called Everlast, per their tech-support any generator with 8kw or better will work fine.
It does works fine. BUT, I have not had the opportunity to run the full 160 amps yet.
It does works fine. BUT, I have not had the opportunity to run the full 160 amps yet.
Everlast PowerTig 250EX, PowerTig 185 Micro, PowerArc 160STH, Miller Trailblazer 301G, Millermatic 140 Auto-Set
Noddybrian.
Could the inverter welding machine that is not 'generator safe', be protected by put an adjustable 'breaker' between the generator and the welding machine connections? Perhaps breaker would be similar to the components that are within the 'generator safe' inverter machines.
Alexa
Could the inverter welding machine that is not 'generator safe', be protected by put an adjustable 'breaker' between the generator and the welding machine connections? Perhaps breaker would be similar to the components that are within the 'generator safe' inverter machines.
Alexa
noddybrian
- noddybrian
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Alexa
Short reply is no - sorry but it's not that simple unfortunately - a " breaker " as I assume your refering to is a device that acts as a fuse - simply switching off when a set current limit is reached - the electronics in the inverter welders that claim to be generator safe monnitor high / low line voltage & high / low frequency ( along with some other stuff depending on model ) and can switch off vital components to protect from damage very very fast - my own AMD Butters 166 Tig / stick does this but the set remains on even after a generator issue in standby mode with an error code on the panel.
I believe if you have a good generator running good true sine wave output of sufficient size & line voltage & frequency are correct there is no reason why you should'nt run any inverter welder - the generator safe models simply have a bit of inbuilt protection in case any of these parameters are out sufficiently to cause damage - many people have used welders on generators without problem and never thought about it - ignorance being bliss ! I would liken it to computers - most people simply plug them into the mains indoors & never give it a thought relying on the power company to provide clean ripple free / spike free power - now they do a fine job most of the time - but you can't take it for granted - so you use surge protection as a minnimum & wherever possible an UPS .
Powering sensitive equipement with a generator means you need to test the output & be sure it's adequate - simply having a plug in box with volts / amps / frequency meters helps to keep an eye on things if the set does not have this on a panel as standard - but again sine wave is the key word & without an oscilloscope your not going to know - I can't vouch for the new Siemens derrived IGBT power transfer modules - but all the older inverters running Mosfets as the switching method suffer terribly from wave form irregularitys & don't behave well or overheat badly with relatively slight waveform defects.
Hope some of this helps - it's not an easy subject to explain well briefly as you need to understand probably more electical theory than alot of readers have or are interested in ! though there are undoubtedly members far better educated in this subject on the forum than me - it does tend to get a bit overly PHD material from the original simple question of " can I do this " though.
Short reply is no - sorry but it's not that simple unfortunately - a " breaker " as I assume your refering to is a device that acts as a fuse - simply switching off when a set current limit is reached - the electronics in the inverter welders that claim to be generator safe monnitor high / low line voltage & high / low frequency ( along with some other stuff depending on model ) and can switch off vital components to protect from damage very very fast - my own AMD Butters 166 Tig / stick does this but the set remains on even after a generator issue in standby mode with an error code on the panel.
I believe if you have a good generator running good true sine wave output of sufficient size & line voltage & frequency are correct there is no reason why you should'nt run any inverter welder - the generator safe models simply have a bit of inbuilt protection in case any of these parameters are out sufficiently to cause damage - many people have used welders on generators without problem and never thought about it - ignorance being bliss ! I would liken it to computers - most people simply plug them into the mains indoors & never give it a thought relying on the power company to provide clean ripple free / spike free power - now they do a fine job most of the time - but you can't take it for granted - so you use surge protection as a minnimum & wherever possible an UPS .
Powering sensitive equipement with a generator means you need to test the output & be sure it's adequate - simply having a plug in box with volts / amps / frequency meters helps to keep an eye on things if the set does not have this on a panel as standard - but again sine wave is the key word & without an oscilloscope your not going to know - I can't vouch for the new Siemens derrived IGBT power transfer modules - but all the older inverters running Mosfets as the switching method suffer terribly from wave form irregularitys & don't behave well or overheat badly with relatively slight waveform defects.
Hope some of this helps - it's not an easy subject to explain well briefly as you need to understand probably more electical theory than alot of readers have or are interested in ! though there are undoubtedly members far better educated in this subject on the forum than me - it does tend to get a bit overly PHD material from the original simple question of " can I do this " though.
Wow. Thank you all for taking the time to respond. An unexpected trip to Indiana to get a car led to my absence in this discussion. I have no real world use for this type of setup, it was more so a curious question that popped into my head one day at work. I'm glad I asked though. I wouldn't have thought of half the things you guys mentioned. I imagine if I needed to go mobile, I'd get the proper Miller or Lincoln for the task. However, this is handy info to keep in the back of the old memory bank. Thanks again Brian, Otto and all the rest. 
You've helped me come to understand this topic much better.
You've helped me come to understand this topic much better.
- Otto Nobedder
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That's also how phase conversion is done, if you need three-phase in a remote area where single-phase mains are all that's available. Many years ago i worked in a little backwoods shop that had two relics... three-phase flywheel punch, and flywheel press-brake, which we'd power up by switching on an old military-surplus phase converter. 240V going in (10hp drive, if I recall) driving a flywheel, 480 3-phase coming out the generator on the other side.WerkSpace wrote:This is how the military does it, when powering an entire building.
Steve S
noddybrian
- noddybrian
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That " military" power conversion was also how early DC welding started - big motor direct coupled to a DC generator welder - not seen them around in recent years but " back in the day " they were common place - every shop had at least one sitting in a corner - looked like an unexploded bomb!
then Murex came out with an oil cooled rectifier about the size of a 40gallon barrel that you could hook any AC power source to - after that I guess things started getting smaller & cheaper so "old school" stuff began to disapear - it's a shame as older technology was built to last nearly forever & could be repaired easily - modern electronics are smaller / lighter & do more to make welding easier - but will it still work after they " drop the bomb" - may not be Russia like we all thought a few years back - but sooner or later some "camel jockey" will.
then Murex came out with an oil cooled rectifier about the size of a 40gallon barrel that you could hook any AC power source to - after that I guess things started getting smaller & cheaper so "old school" stuff began to disapear - it's a shame as older technology was built to last nearly forever & could be repaired easily - modern electronics are smaller / lighter & do more to make welding easier - but will it still work after they " drop the bomb" - may not be Russia like we all thought a few years back - but sooner or later some "camel jockey" will.