Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 16 Times in 11 Posts
Re: A Dumb Alternator Question...
As Sundance said, "You keep thinkin' Butch; it's what you do best."
Alternators have three windings, so the AC they put out is three-phase, which would be nice for running a three-phase motor. Not so nice for anything else. For single phase, like house current, you would tap one winding, and get 1/3 of the total output potential.
Second, it's regulated to around 15-16 Volts so that after it's rectified to DC you've got about 14 Volts. The regulator could be disabled, but I doubt the internal insulation could tolerate 120 Volts very long, even if it will produce that much Voltage.
The frequency is proportional to alternator speed. When the alternator is spinning 3600 rpm you will get 60 cycles per second on each leg, so you would need to control engine speed carefully for anything that was AC frequency sensitive.
As for how much you can get out of it, alternators are rated in Amps. A 60 Amp alternator will put out 60 Amps DC, a little more AC because there's not the (minimal) loss in the diodes, but that's on all three phases combined; you'd get 20 Amps on each leg. But that's at 16 Volts. As voltage increases the maximum current will drop dramaticly. I'm sure somebody on the board has experimented taking AC out and knows what they can do.
For about $30 at Sam's Club you can get an electronic inverter that will connect to a 12V battery and put out 400 watts of 120V 60 cycle. That's enough to run a small TV and VCR, or a 3/8" drill if you don't push it too hard. It's the size of 3 or 4 paperback novels stacked together.
Inverters are available in sizes up to huge, but they get pretty pricey. That one at Sam's is relatively cheap because Sam's ordered huge quantities of them.