PWM - Inductive loads vs. Frequency vs. Transistor temperatures

[HWS]

Hello everyone.

The PMU User Manual states the following:

I would like to know if there is any way to calculate the best frequency to PWM activations on inductive loads based on its wattage? For example: If I’m going to run a 450W radiator fan and I don’t want to overheat the transistors, which frequency would be best?

[ellisd]

Its was trial and error for me. Listening for what frequency gave the “cleanest” start. I also looked at the current draw to see what gave the smoothest current draw (lowest oscillations)