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Other Stuff => Other Topics => Topic started by: silverfox on January 03, 2021, 08:44:14 pm

Title: Automotive Alternator- 3 Phase?
Post by: silverfox on January 03, 2021, 08:44:14 pm

I've seen where some people convert an automotive alternator into a welder power unit. In other instances, others have gotten 90 or more volts out of rewiring the output.


Are there any explanations regarding this? Are there 3 windings in the alternator?


Thanks guys, and have a good 2021.


silverfox.

Title: Re: Automotive Alternator- 3 Phase?
Post by: DummyLoad on January 03, 2021, 09:27:13 pm

yes auto alternators are 3 phase. most have a trio of diodes mounted internally. and yes, 3 windinings.

there are plenty of vids floating around on how to repurpose auto alternators, including converting them into wind energy power plants.

you can also turn one into a 3 phase motor with some clever hacking of a VFD.

&ab_channel=austiwawa

--pete

Title: Re: Automotive Alternator- 3 Phase?
Post by: silverfox on January 03, 2021, 10:00:54 pm

DL: "you can also turn one into a 3 phase motor with some clever hacking of a VFD."


I've seen that on youtube. Good power too. Not long ago I was looking at washing machines and noticed they've got freq drives now. Smooth. Too bad when it breaks no one can fix it for less then $300; Or maybe not at all.


So to get the highest voltage you would connect all three phases in series? How would you know you weren't connecting the fields in some sort of, "Bucking" fashion.


I have to wonder what these inverter generators are doing. Permanent magnet genny, or an auto alternator style design. You only need a small mag field to power the windings as a regenerative sort of start up force.


Thanks DL.

Title: Re: Automotive Alternator- 3 Phase?
Post by: PRR on January 04, 2021, 10:51:08 pm

Alternators make >12V at idle. Voltage rises with RPM. The Regulator dials-back excess voltage. If you clobber the regulator, 90V is easy. At about 4500rpm engine speed.

Title: Re: Automotive Alternator- 3 Phase?
Post by: silverfox on January 05, 2021, 12:30:30 am

Quote from: PRR on January 04, 2021, 10:51:08 pm

Alternators make >12V at idle. Voltage rises with RPM. The Regulator dials-back excess voltage. If you clobber the regulator, 90V is easy. At about 4500rpm engine speed.

I've read the newer regulators yield 14 7 @1000. I did build a charging system from a 5hp + alternator/battery. Problem at the time was the fuse got so hot at 60 amps it set the mounting block, made of wood, on fire. Had to terminate the experiment. But it did work, and not at 4500 rpm. Toyota alternator.


I'm starting to think in terms of the video where the fields are excised from the diodes to make a 3 phase motor; or, generator? What would be the max voltage from the windings if in phase? 36 VDC? How many amps and volts in series? Assume a 100 amp alternator. 1.2 kw at either 36 or 12 volts. Would that also be the hp output if used as a motor?


silverfox.

Title: Re: Automotive Alternator- 3 Phase?
Post by: PRR on January 05, 2021, 04:21:09 pm

> What would be the max voltage from the windings if in phase?

They can't be in-phase. 

> How many amps and volts in series?

Zero.

Title: Re: Automotive Alternator- 3 Phase?
Post by: shooter on January 05, 2021, 05:27:18 pm

that's what I was thinking.
I worked on a system that used 6phase AC, rectified eventually to BIG VDC, the circuit that accomplished that was a potted black box that made skunk spray smell good when it burnt up.

Title: Re: Automotive Alternator- 3 Phase?
Post by: silverfox on January 05, 2021, 09:30:15 pm

I'm off to YT. Clearly I have some learning to do.


Thanks for all the replies,


silverfox.