Hi all,

A quick OT question. What is the minimum safe PWM frequency for small
coreless DC motors. The manafacturer doesn't specify one. From what I
understand, using a low PWM frequecy causes the coils in the motor to
loosen up because of vibration.

Also, what are the advantages of using a coreless motor over an iron core
one? I'm talking about small DC motors maybe upto 6 watts at 18 volts.

Shahid