On Jan 8, 3:30*am, Bruce L. Bergman
wrote:
On Thu, 07 Jan 2010 10:04:48 -0600, Ignoramus30285

wrote:
I also called a US Motors distributor in my area (the motor in
question is a US motors motor).

He said that a 1750 RPM motor is safe to overspeed to 2750 RPM.

* And last I checked, 3600 is more than 2750. *You might be able to
get a few percent over, but anything past 3000 is a crap-shoot.

* They usually set those limits because the test motor started to come
apart at 3600 but held long-term at 2750, and they left a cushion in
the max speed ratings.

-- Bruce --

All small ac motors can be operated safely at 3600. Many can are
wound on the same frame for either 2 or 4 pole windings. A one HP
56C motor has no physical changes, other than the windings, at either
speed.