Is there a guide to building a 3-phase AC welder?

I was looking through the MANY guides on the web for weldernators and I'm in the midst of putting it together. It suddenly occurred to me that my dad used to own both 5 and 3 phase AC welders and I thought "wait a minute, an alternator is 3 phase AC". I searched and searched but I'm doing a lot of searching on a smartphone because of a really long couple of work weeks, plus I suck at Google apparently. (If I wanted to buy one I could find that.)

Anyway, I'm just not sure of how a 3 phase AC welder works. Maybe it just turns it into DC. They were just arc welders anyway.

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lemonie6 years ago

5 phase?
You really need a 3-phase supply, I'm not convinced alternators produce 3-phase and in any case they're not good for welding-currents.

Andale_The_Great (author)  lemonie6 years ago
Rare, but you can get 5 phase wired to your home if u wanna pay for it.
How are you not convinced alternators produce 3 phase? ITs the nature of how they're built. They don't produce it as cleanly as what you can get from the power company of course.
I don't know what 5 phase would mean, in the sense that three phase is meant.

Three phase should be 120-120-120 or 220-220-220
5 phase would be, I presume, 220-110 220-110 220 or some combination thereof.

Andale_The_Great (author)  steveastrouk6 years ago
It has to do with how many field windings are in the generator (or alternator in this case). Each one delivers AC sine waves of whatever voltage you happen to be creating. Common alternators run three phase because they can produce cleaner DC power than the old generators which were two phase and the DC was very poor. Each of the field windings is placed 120 degrees apart rather than 2 at 180 degrees or 4 at 90 degrees (though I don't understand why 4 windings is still 2 phase and not 4, I've looked it up and that's what it seems to be called).
ANYWAY! The point is that because the top half of the sine wave is added together by use of a diode rectifier (not explaining all that) so the more "humps" the closer to real DC.

It would always be the same voltage.

Did I explain this poorly? I'm tired. Sorry.
I've worked in high power electrical engineering in the UK for 30 years and I ain't seen a 5 phase alternator. I've seen 3 though....

Alternators produce three phases because thats the most economical way of generating a rotating magnetic field in an AC motor and the most economical way of transforming power in a polyphase system. Its got nothing whatsoever with the ability to turn into DC.

Andale_The_Great (author)  steveastrouk6 years ago
I never said there was a 5 phase alternator (I imagine that would be huge and pointless), only 5 phase AC welders.

I don't know what you're trying to say about sine waves being built instead of created but I will admit I should have said that it generates a sine wave, the point isn't where, just the fact that the power fluctuates and that's why you would even have or use 5 phase, it's not necessary for most applications but professional welders will know the difference.
Show me a link to a 5 phase welder.
Andale_The_Great (author)  steveastrouk6 years ago
First off, off topic. Secondly, research it yourself. I know my dad paid huge bucks to have 5 phase run to his shop to put a large welder on. I know they exist.
I tried simply "5 phase welder" it does not give me any hits other than electronic inverter sets. "5 phase supply" doesn't generate any useful hits. You're the one who's insisting they exist. Show me some proof. I haven't met any polyphase distribution system other than 3 phase in 30 years in practice. There is no practical reason to need one.

Andale_The_Great (author)  steveastrouk6 years ago
Look, I don't care what google gives you. I told you to look it up yourself cuz I don't NEED to prove they exist. I know they do even if they're hard to find. I also know it was able to use 3 phase as well so it wouldn't only be labeled for 5 phase.

This is still off-topic and I'm officially done discussing this, there's no point to it.

If you're gonna keep posting here then why not try sticking to the question I asked about.
A three phase welder is the same as a single phase welder, with a different transformer. To make one, you need a transformer with a big air gap.

There is no such thing as a 5 phase welder, so you can stop looking.

OK ?
In a real alternator BTW, sine waves are NOT created in the field windings at all. They are built.


You'd have to reconfigure the wiring, but one won't handle welding current for long.

so if im right, your asking how to build a welder that will run on standard 110v mains current? if so, this instructable should be the one you want.