If you want 60 HZ like the OP, then you MUST run a 4 pole at 1800 RPM
and a 2 pole at 3600rpm. Not to mention, the windings are designed to
produce a specific voltage at those speeds. If all you want is junk
power output with no voltage OR frequency regulation, run them at other
speeds.

wrote:
On Sun, 22 Nov 2009 23:22:06 -0600, RoyJ
wrote:

Not really. An 1800 rpm generator will be a 4 pole unit, a 3600 rpm
generator will be a 2 pole unit. A 4 pole, 1800 rpm unit is usually
MUCH quieter than the 2 pole versions. And engine life at 1800 rpm is on
the order of 5x to 10x the life at 3600 rpm.

Yes, if you want 60 Hz at 1800 RPM you use a four coil machine, etc.,
but the generator itself doesn't care a bit about whet RPM it spins
at. You can run a 4 pole generator at 1000, 1800 or even 3,000 RPM
(assuming that the machine was properly made) and it is perfectly
happy to produce electricity. As I said, it doesn't care and it
certainly doesn't make any more noise at high RPM then it does at slow
speeds.

Most generators made today use non-friction bearings and if kept
lubricated will last for years and the RPM is nearly meaningless to
them.

You will note that when I use the term "generator" I am talking about
the electrical generating device.

And as I said, the 1800/3600 RPM thing was mainly about engine life
and noise.

Mechanically the generator itself doesn't care what RPM it turns at,
Other then possibly accelerated bearing wear which is minimal with
ball/roller bearings. The gumph about 1800 RPM vis-a-vis 3600 was
mostly heard from the marine users and was mainly worry about engine
life and noise.

Regards,

J.B.
Regards,

J.B.