# Single Phase Alternator



## RePhase277 (Feb 5, 2008)

I have a portable generator, single phase 5500 watt. It is recoil start but I thought it would be peachy to make it electric start. There is no easy way to do this mechanically with a starter motor.

I know that three phase alternators can be ran as motors by energizing the rotor with DC and applying 3 phase AC to the windings. I wonder if the same thing can be done with the single phase alternator of my generator. I could set up some control circuits to handle the switching. So during start, the alternator would temporarily be used as a motor to start the engine, then the controls would switch the wiring back over to alternator mode.

The thing is, I can't see a way to get a field offset in the single phase windings to cause rotation. The alternator has 4 leads for two windings, but they are parallel in phase. I know you motor guys know a lot more than I do about this. Is it possible?


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## Southeast Power (Jan 18, 2009)




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## frenchelectrican (Mar 15, 2007)

RePhase277 said:


> I have a portable generator, single phase 5500 watt. It is recoil start but I thought it would be peachy to make it electric start. There is no easy way to do this mechanically with a starter motor.
> 
> If your generator engine do have a mounting spot for starter then you can able install the starter and some case you may have to add a ring gear or change flywheel with ringgear on it.
> 
> ...


Ya cant do that with single phase windings at all. due the winding is 180° out of phase so to try to start them in reversed mode it will not able do it.


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## RePhase277 (Feb 5, 2008)

I thought so. 

The engine casting has a provision for a starter because there is an electric start model of this generator, but I'd need to put a hole in it to allow the starter access to the ring gear that I'd also need to install.

I'm not licked yet. I'm still studying it.


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## Southeast Power (Jan 18, 2009)

A Swiss Arny knife can do a dozen things but not a single one very well.


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