If the source voltage of a DC motor is increased, which of the following will decrease?
A. Full load current.
B. Starting torque.
C. Starting torque, operating speed, full load current.
D. Operating speed.
Answer: A
Share your understanding of this question with the correct explanation.
If the source voltage of a DC motor is increased, the full load current will decrease.
When the source voltage is increased, the back electromotive force (EMF) of the motor also increases. The back EMF is directly proportional to the speed of the motor. As the back EMF increases, the voltage difference between the source voltage and the back EMF decreases, leading to a decrease in the current flowing through the motor. This decrease in current results in a decrease in the full load current of the motor.
Therefore, option A is the correct answer.