Help: Can I convert this 3600 RPM Stamford gen --> 1800 RPM

[islander]

Hi there,

My first post but am wondering if anyone might know if I can convert this Stamford generator to a 1800 RPM Single Phase?

It is a 12 lead gen, I was thinking it would probably need a different AVR ??

Also what would the KW rating end up being?

Thanks

[Shipo]

You can't, because your head is a two pole generator. To have a 1800 rpm you will need 4 pole. To understand that read here...

http://en.wikipedia.org/wiki/Alternator

[Thob]

I agree - you can't convert it.  If you attempt to run it at 1800, you would get 30 Hz and about half the voltage.  The AVR would attempt to compensate for the voltage loss, possibly over driving the field in doing so.  Newer AVRs are designed to detect low frequency and not burn up the field at low RPM.  The AVR can't do anything about the frequency change.

If it's a two bearing generator, you can use a belt and pulley system to run the engine at 1800 and the generator at 3600 RPM.  Lots of people do that with micro-V belts, the same thing as the serpentine belts on automobiles.  For that matter, with different sized pulleys you can choose a lot of different engine speeds and still get the alternator to run at 3600 RPM.  You still have to match the power requirements, of course.

If it's a single bearing generator which directly couples to a flywheel, you're kinda stuck.  You could possibly machine a holder for a second bearing, but that's a lot of work.  Probably better to sell it and buy what you need.

[islander]

Thanks for the replies.

Too bad as their is a source on eBAy for these for $200.00.

My 10KW Stamford shorted out recently and I have been wanting to replace it.
Not sure If I should try the Chinese knock-offs, try a mecca-alte, or just buy a new Stamford alternator.

[Thob]

Is there any possibility that your stamford is repairable?  What shorted out on it?  Does it just need the voltage regulator?