Q48: A motor in normal operation carries a direct current of 0.850 A when connected to a 120-V power supply. The resistance of the motor windings is 11.8 V. While in normal operation,
(a) what is the back emf generated by the motor?
(b) At what rate is internal energy produced in the windings?
(c) What If? Suppose a mal- function stops the motor shaft from rotating. At what rate will internal energy be produced in the windings in this case? (Most motors have a thermal switch that will turn off the motor to prevent overheating when this stalling occurs.)
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