A differentially compound motor under high-over-load conditions will behave like a / an
A. series motor.
B. shunt motor.
C. AC synchronous motor.
D. Cummulative compound motor.
Answer: A
Share your understanding of this question with the correct explanation.
The answer is A. series motor.
A differentially compound motor has two field windings, a shunt field winding and a series field winding. The series field winding is connected in series with the armature, while the shunt field winding is connected in parallel with the armature.
Under normal operating conditions, the shunt field winding dominates and the motor behaves like a shunt motor. However, under high-over-load conditions, the series field winding begins to dominate and the motor behaves like a series motor.
This is because the series field winding has a lower resistance than the shunt field winding. As a result, the series field winding carries more current under high-over-load conditions. This increased current produces a stronger magnetic field, which causes the motor to speed up.
The increased speed of the motor causes the current in the series field winding to increase even further. This positive feedback loop can cause the motor to run at a very high speed, which can damage the motor.
For this reason, differentially compound motors are not typically used in applications where they may be subjected to high-over-load conditions.