A fully assembled DC motor model, the motor does not rotate after the power is turned on, and the coil rotor rotates normally after the rotor is moved by hand, then the reason why it does not rotate at the beginning may be_______
A. Internal short circuit of coil
B. Poor contact between brush and commutator
C. The magnet's magnetism is not strong or the current in the coil is not large enough
D. The coil is exactly in the equilibrium position
Answer:D
A fully assembled DC motor model, the motor does not rotate after the power is turned on, and the coil rotor rotates normally after the rotor is moved by hand, then the reason why it does not rotate at the beginning may be_______
A. Internal short circuit of coil B. Poor contact between brush and commutator C. The magnet's magnetism is not strong or the current in the coil is not large enough D. The coil is exactly in the equilibrium position