motor lamination problem
motor lamination problem
(OP)
After months of hard work, we tested our second prototype motor today with disappointing results. The motor amp draw is too high and the motor shaft quickly overheated. The problem was determined to be the stator laminations with a
c5 coating not providing enough insulation. We will try spraying a varnish on each lamination and building a new rotor for testing tomorrow. It's a squirrel cage rotor.
The motor is a small 2 hp. induction two pole, three phase, 208 volt AC motor that runs at about 12,000 rpms off a VFD at about 200 Hz.
We tried a C3 lamination but it didn't laser cut well. Question is does anyone have a recommendation for a better lamination material or a suggestion how to build the best rotor??
Thanks.
c5 coating not providing enough insulation. We will try spraying a varnish on each lamination and building a new rotor for testing tomorrow. It's a squirrel cage rotor.
The motor is a small 2 hp. induction two pole, three phase, 208 volt AC motor that runs at about 12,000 rpms off a VFD at about 200 Hz.
We tried a C3 lamination but it didn't laser cut well. Question is does anyone have a recommendation for a better lamination material or a suggestion how to build the best rotor??
Thanks.





RE: motor lamination problem
did you try simple core loop test with thermography to look for hot spots ?
what is the lamination thickness?
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(2B)+(2B)' ?
RE: motor lamination problem
Thanks.
RE: motor lamination problem
The problem ended up being that we were using a non-magnetic 303 stainless steel motor shaft (need corrosion resistance). Using the same rotor, if we switch to a 1018 steel shaft, the amps and temp drop dramatically (about 70%).
RE: motor lamination problem
At first glance, I wouldn't have thought shaft permeability would be important. We certainly don't want homopolar flux.
Then I looked up this excerpt from EASA's Tech Note 43 (Making and Replacing Motor Shafts):
It makes sense that for 2-pole motor, the flux path goes directly between 180-opposite poles and can pass right thru shaft... for 4-poles the flux flows more circumferentially in the rotor backiron and should not be a problem. For this hi-speed application I'm sure you've got a 2-pole
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(2B)+(2B)' ?
RE: motor lamination problem
Will keep you posted.
RE: motor lamination problem
Bill
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"Why not the best?"
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