Homemade TIG machine

[OSUWeldEngineer]

Ok, this is probably a stupid question, but I read a post on here somewhere that had a link to someone that made their own TIG welder using a car battery, an alternator and a 5hp motor. It said that it put out DC. There was no mention of any rectifier being used or anything, so I'm confused as to how it puts out DC. I thought alternators were AC, because otherwise it wouldn't charge the car battery. Am I missing something?

-Adam

[GTA/Spec]

Yes,
Although alternators produce alternating current, all automotive alternators have rectifiers and voltage regulators integrated into them. An alternater therefore produces a DC output.

[Timinmb]

They make a decent dc source as they generate 3 phase ac internally then rectify it (as mentioned previously). The three phase input to the rectifiers makes for a smoother dc output as the waves forms overlap and therefore have less "ripple".

[BillC]

Originally posted by OSUWeldEngineer
<<SNIP>>I thought alternators were AC, because otherwise it wouldn't charge the car battery. Am I missing something?

Adam,

I don't think an AC signal would charge a battery at all... It would charge while it was positive, then discharge when it was negative. The net result would be zero...

Make sense?

[OSUWeldEngineer]

ahhhhh it's all makin sense now....thanks a lot guys

[Mike W]

You could do something like this for a tig on the cheap.