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Don Foreman Don Foreman is offline
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Default Another question, induction motors on 50hz, limited duty

On Tue, 24 Nov 2009 18:05:41 -0800, Jon Anderson
wrote:

First, thanks everyone for the generator info. Looking into the cost, I
started to wonder if it really would be cheaper overall than replacing
the power hand tools down under. It probably really is, considering some
of the power tools I would take I've had some 10-15 years and still
haven't used once. If I only replaced the hand drills and grinders,
maybe not.

But... I've been told several times that AC brush motors run fine on
50hz, just a bit slower. I took a good hard look around, and the only
110v AC items I have in the shop (outside of my nice shop stereo) is a
vacuum pump, my Baldor, and two bench grinders. The Baldor is not rated
50hz, and it was mentioned here some time back in response to other
questions of mine, that induction motors will overheat on 50hz. But if
I'm only running it for a maximum of a couple minutes at a time,
generally only around 30 seconds (and only maybe a dozen times a month),
it would seem to me that the motor is likely to last the remaining 15-20
years I think I'm going to be active.


It's a good bet. The thermal time constant of most FHP induction
motors is probably something like 10 to 20 minutes. Producing a bit
more heat at 50 Hz for a couple of minutes, followed by a "rest" of
that long or longer, won't raise the motor temp enough to be an
issue.