A 3 V battery-operated toy fan runs on a miniature DC motor
PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
A 3 V battery-operated toy fan runs on a miniature DC motor. After several hours of use it suddenly stops, although the battery is still fresh. On opening the motor housing, it is observed that the carbon brushes have worn down so that they no longer touch the split-ring commutator.
(i) Identify the immediate electrical consequence of the brushes losing contact with the split-ring.
(ii) Explain why this consequence prevents the motor from running even though the battery is still connected.
(iii) Suggest two practical steps that should be taken to restore normal working of the motor and justify each suggestion.