"Gunner Asch" wrote in message
...
On Tue, 20 Dec 2011 00:20:30 -0800, "Bruce L. Bergman (munged human
readable)" wrote:

On Mon, 19 Dec 2011 18:50:42 -0800, Gunner Asch
wrote:

On Mon, 19 Dec 2011 12:35:44 -0700, "Bob La Londe"
wrote:

VFDs & 3 Phase Motors

All-righty then. This may sound stupid, but when you run a 3 phase
motor
off of a VFD what is your speed range relative to the original speed of
the
motor?

Approximately of course. Mileage will vary I am sure.

From about 8% to 200% of original rated speed range.

Simply because the bearings in the motor may not take higher
speeds..this for a 1750 RPM motor

A 3600 RPM motor shouldnt be run any faster than about 150% of rated
speed..for the bearings and the armature (might shatter)

If all else fails, Read The Friendly Manual for the motor.

The ones that are rated for "Inverter Duty" (a VFD) will have all that
info listed in the catalog and on the cut sheets.

-- Bruce --

True indeed. But few Hardinges (for example) were made or intended for
use with inverters so such info can be very very hard to find.


And
until the last decade or less..inverter duty motors were exceptionally
rare.


And from what I have been able to find a quite a bit more expensive.