PWM vs. Linear Amplifier effect on motor efficiency and heat losses in motor coils

[mawad]

Hi
I have a question related to PWM vs. Linear Amplifier. I know the PWM amplifiers run cooler than standard linear power amplifiers and hence the PWM amplifiers has higher efficiency. I am wondering what about the motor itself. Are both PWM vs. Linear Amplifier produces the same heat losses on the motor?

 

[Skogsgurra]

Somewhat higher (a few percent) losses when you run the motor on PWM. But the losses in a linear drive, if anyone should ever get that idea, are enormous. At low speed, the losses are approaching 100 percent.

Gunnar Englund

http://www.gke.org

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Half full - Half empty? I don't mind. It's what in it that counts.

 

[cswilson]

I agree with Skogs. There are slightly greater losses in the motor due to the current ripple from the PWM, but the losses in a linear amplifier are FAR greater than in a switching amplifier.

Linear amplifiers are real specialty items now, really only used in super-precision applications that cannot tolerate the vibration or EMI from a switching amp.

Curt Wilson
Omron Delta Tau

 

[mawad]

Many thanks for Skogsgurra and cswilson