"John Popelish" wrote in message
. ..
colin wrote:
(snip)

are there any other significant problems associated with running an
induction motor at high speed ?

I think eddy current and hysteresis heating of the stator laminations are
the biggest limitations, after you get past mechanical resonances it the
rotor that make the shaft bend. I have seen some pretty high speed 2 pole
induction motors.

http://scitation.aip.org/getabs/serv...cvips&gifs=yes
http://adsabs.harvard.edu/abs/1991crin.rept.....M
http://stinet.dtic.mil/oai/oai?&verb...er =AD0601968

yeah I gues iron losses go up, im running about 10-20x normal speed wich is
stil less than 1khz,
dont losses go up linearly with frequency ?
if iron losses are similar to copper losses I gues il have to derate it
rather a lot.

at least the rotor should be electrically similar as it only sees the slip
frequency.

those motors look quite cool, although I only see the abstract.

im gona get some of that material, i got some magnets from the same place
too.

im also gona see if i can re magnetise the rotor of my current motor to see
if it can be made to be more of a sinewave so have less torque ripple. might
be easier, although might take a few tries.

Colin =^.^=