Fisher Price Motor Power

[Mike Betts]

Originally Posted by vamfun

Interesting ...Question to you and Joe J.: What continuous current do you think can we run if we are in stall without tripping the internal protective device?...

Chris,

While I am humbled among the likes of Al and the Good Doctor, I'll give you my 2 cents...

A motor at stall is delivering no mechanical power. All of the electrical power, even constant current, is converted to heat. Most external cooling that teams implement is over the case and not forced into the motor. The heat will build up in accordance with the thermal resistance of the internals of the motor.

This will likely happen very fast.

That little fan inside the FP is directly cooling the motor windings. If that little fan stops, my experience is that failure will occur very quickly.

In my opinion, the PTC added to the FP in recent years is to attempt to save a child's extremity or to mitigate an actual fire in the toy for which the motor was designed. It may not be fast enough to limit damage to the motor.

I would not design a system where the motor could stall.

JMHO,

Mike