[Marc S.]

If your motor has smoked then i would suggest replacing it.

When the tetrix motors smoke, its not because of the armature components or the brushes. Inside the endbell of the motors is a resistor. This is designed to burn at a very low amperage rating. When this resitor burns it usually smokes and breaks the circut. If your motor still works even after smoking then i would guess that the proformance has dropped and it will stop working with continued use.

If the resistor was not there then the motor would continue to get hotter until it would actually burn up. This is when the wire around the electromagnets in the armature gets realy hot and melt the thin insulation coating causing the wires to touch each other and short. When this happens the imediate result varies because the melting of the wire cannot be expected to occur equally throughout the motor. In this case (the tetrix motor) the three electromagnets on the armature are no longer putting out the same magnetic froce aswell as now pulling a different amount of amp draw. This causes the motor to be very unbalanced and create excess heat because the motor is now constantly trying to slow down and speed up thousands of times per-second. This will cause the speed and power output of the motor to decrease until the motor stops turning all together. Disproving the (untested) "theroies" you have posted. (which by the way are irrelavent when talking about the tetrix motors, the motors i think he was talking about are the standard DC motors that don't have a resistor.)