Motor Temperatures of inverter duty rated vs non inverter duty rated
Motor Temperatures of inverter duty rated vs non inverter duty rated
(OP)
Looking for some clarification....
I recently had a discussion involving motor surface temps.
I am under the impression that an inverter duty rated motor (per MG1 part 31) would not necessarily run cooler as far as surface temperature is concerned when compared to a non inverter duty rated motor. I realize there are several factors in motor design that would effect the surface temp. Lets assume we had two identical motors, one rewound for inverter duty and one not.
I recently had a discussion involving motor surface temps.
I am under the impression that an inverter duty rated motor (per MG1 part 31) would not necessarily run cooler as far as surface temperature is concerned when compared to a non inverter duty rated motor. I realize there are several factors in motor design that would effect the surface temp. Lets assume we had two identical motors, one rewound for inverter duty and one not.





RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
Keith Cress
kcress - http://www.flaminsystems.com
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
The VFD duty motors fail more due to improper insulation (against high dv/dt) than due to temperature.
Muthu
www.edison.co.in
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
The early VFDs put out a crude 'square' wave that was very rich in harmonics. That square wave made the motor run with a high percentage of torque ripple, effectively accelerating/decelerating within every cycle. The repeated acc/decel heated the motor a lot more than a sinewave did,
So, that is why inverter motors were less efficient than DOL motors. But not these days.
Inverter duty motors is almost entirely about insulation. There may be some influence from lamination thickness and I think that most motors have thinner laminations today. Not quite sure about that. Muthu?
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
Today the core laminations have been reduced to just 2 thicknesses - 0.35 & 0.50 mm, with the lower thickness costing a bit more.
Muthu
www.edison.co.in
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Motor Temperatures of inverter duty rated vs non inverter duty rated
non inverter duty motors (10:1vt 4:1ct) have class f insulation 155c (311f)
There are alot of Variables when selecting vfd motor combination
nathan