Do welding units, such as a Multimatic 220 AC/DC (PDF spec sheet), need a specific generator to power it? For example, does that unit require the Miller Bobcat 260 (PDF spec sheet)? Or can cheaper generators be used?

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  • I'm not seeing the "shopping" reference in the VtC. If one were to remove brand names, it remains a perfectly reasonable question. This has a very reasonable answer that's not at all shopping specific, but does get around to noting that the linked references are attempting to sell a particular brand of equipment and suggests contacting the mfgr for more info.
    – FreeMan
    Jun 23, 2020 at 12:47

1 Answer 1


A welding unit needs a power source compatible with its power requirements. For the Miller Multimatic 220 AC/DC, that varies with your intended usage and amp draw. If you're intending to stick weld heavy steel at 200 A (welding current), you're going to need a 240 volt power source rated at at least 32 amps (i.e., 40 or 50). Also keep in mind your duty cycle; the welder is only good for a 15% duty cycle at that heavy power draw...10 seconds welding, 50 seconds resting.

On the other hand, if you keep your stick welding amp draw at 90A or less (40% duty cycle) or TIG welding at 130A, the welder will be perfectly happy with 120V power. (Not from a regular wall outlet, though, not at those amperages...you'd need a special 30 amp 120V outlet).

Now, while Miller very well may want to sell you their generator (and it might be worth considering to have equipment you know will work and play well together), the welder really won't care where the power comes from as long as it meets the voltage and current supply requirements. If you have another generator which is capable of supplying the load, by all means use it (Do make sure you have compatible plugs and cords first, of course!). If you're just using the machine in your own garage or shop, you really don't need a generator at all...just call an electrician to have the proper outlet installed wherever you plan to use the welding machine.

Editing To Add: I see that the Bobcat is a welding machine as well as a generator, so if you purchase it you will only need the one piece of equipment. It's up to you if you would rather have two separate machines (the Multimatic welder plus whatever lower-priced generator you choose).

  • "the welder really won't care where the power comes from as long as it meets the voltage and current supply requirements" - They told me the random rpm spikes in a generator would fry the circuit board because it has nothing built in to protect it from random spikes in power.
    – adamaero
    Jun 22, 2020 at 19:30
  • weldclass.com.au/blog/…
    – adamaero
    Jun 22, 2020 at 19:33
  • 1
    I note that that site is trying to sell their brand of welder. But it would be a wise precaution to check with the manufacturer of the welder you have in mind and ask what their recommendations are for operation on a generator.
    – ehbowen
    Jun 22, 2020 at 20:44

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