In a student-made model of a simple electric motor, the split-ring commutator is accidentally replaced by a complete conducting ring. Brushes remain in contact with the ring as before.
a. (i) Explain the intended role of a split-ring commutator in a simple electric motor.
b. (ii) Describe what will happen to the rotation of the coil when a complete ring is used instead of a split ring. Give reason for your answer.
c. (iii) The motor sometimes stops after running for a while because one of the brushes loses firm contact with the ring. Explain how this fault affects the current direction in the coil and, consequently, the motion of the coil.