The speed of a D.C. shunt motor can be increased by_______________?
Correct answer: B. increasing the resistance in field circuit
- A. increasing the resistance in armature circuit
- B. increasing the resistance in field circuit
- C. reducing the resistance in the field circuit
- D. reducing the resistance in the armature circuit
Explanation
Increasing field-circuit resistance weakens the field flux, and since motor speed is approximately inversely proportional to flux, the speed rises. This is called field or flux control.
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