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Help Identifying Specifics

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Old 11-14-2017, 10:19:12 PM
edahlstrom edahlstrom is offline
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Default Help Identifying Specifics

I'm new to the forum and was lead here when searching for information on an old Onan Generator that came with the barn. It is a W3M, 3KW, Serial #42.23450.

What puzzles me is that the I.D. Tag clearly lists the RPM as 1200, see photo attachment... And, the 1200 RPM is unusual.

I was able to download a Technical Manual that was printed in 1944, but, from what I can discern, is unit is older by a couple of years... Maybe 1942?

I was hoping someone could tell me anything, just based upon the I.D. tag. I'm looking for a background starting point, and maybe some accurate tech manuals.

Thanks for any help.
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Old 11-15-2017, 12:30:30 AM
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Motorhead Motorhead is offline
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Default Re: Help Identifying Specifics

A 1200 rpm generator has a 6 pole rotor in the generator to get 60 cycles.
A 1800 rpm generator uses 4 pole rotor for 60 cycles.
A 3600 rpm generator uses 2 pole rotor for 60 cycles.
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Old 11-15-2017, 02:14:43 AM
len k len k is offline
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Default Re: Help Identifying Specifics

Rpm =120*hz/#poles

Where hz =60 hz
#poles =2,4,6,8,10,12,14,16,18, 20 ........ to infinity
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