Attività

The starter motor in your automobile is a DC motor. If you were to accidentally reverse the battery polarity, the DC motor would still rotate in the same direction. Reversing polarity of the battery will not cause the motor to rotate in the opposite direction.

To reverse the direction of rotation of this type of motor, either the current through the stator winding or the current through the armature must be reversed. Reversing both of them will result in the same magnetic polarities between the armature and the stator poles. This results in the same direction of rotation.

The industry's standard for reversing the direction of rotation of a DC motor is to reverse the direction of the current through the armature. When a DC motor has more than one set of windings, shunt and series, as well as interpoles, the currents through all the stator windings would need to be reversed in order to change direction of rotation. This is far more complicated than merely reversing armature current.