| 摘要 |
A D.C. motor includes a brush and commutator used in starting the motor, but which are not used during the running cycle of the motor. The rotor is formed of a permanent magnet. The stator includes a pair of opposite pole driving coils arranged 180 DEG from each other. A sensing coil is placed halfway between the two driving coils. A starting coil is also included halfway between the driving coils and directly across from the sensing coil. Brushes are mounted on the rotor which contact the stationary commutator when the motor is at rest or just starting. As the motor speeds up, the brushes are centrifugally removed from the commutator, thus breaking the starting circuit.
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