Another 3-phase DC motor question

My questions are concerning these kinds of motors: http://www.nidec.com/admtypem/admtypem.htm

Does it hurt these motors to be energized but not rotating? If so, what is the danger? Overheating the controller chip?

If that is the case, would adding a second or third .33ohm resistor in series with the resistor that's already on the controller board provide added protection? I realize that would reduce the torque output but that's okay.

Thanks GB

Does it hurt these motors to be energized but not rotating?

No

If so, what is the danger?

None

Overheating the controller chip?

No

Excellent :)

thanks

These motor controllers take a PWM or pulse input to determine the speed and control the motor accordingly. Since they are hall commutated the only way to have the motor coils energized and not have the rotor turn is to physically block the rotation. The combination of motor and controller is easiest thought of as just another standard DC motor I think (probably with superior speed regulation).