If a DC motor is connected across the AC supply it will
A. Not run.
B. Run at normal speed.
C. Run at lower speed.
D. Burn.
Show Answer
Answer: D
Share your understanding of this question with the correct explanation.
If a DC motor is connected directly across an AC supply, it will likely burn or get damaged.
DC motors are designed to operate on DC (direct current) power sources, where the current flows continuously in one direction. On the other hand, AC (alternating current) power sources have currents that periodically change direction.
When a DC motor is connected across an AC supply, the motor will experience rapid and continuous changes in the direction of current flow. This can lead to several issues:
- Heating: The motor windings and other components are not designed to handle the alternating current, resulting in excessive heating and potential damage.
- Torque pulsations: The fluctuating current can cause erratic torque pulsations, leading to mechanical stress and possible motor failure.
- Loss of efficiency: AC current may not provide the necessary magnetic field for efficient motor operation, resulting in reduced performance and speed control.
- Uncontrolled operation: The motor may not run at its intended speed or operate as expected, leading to unstable and unpredictable behavior.
Therefore, connecting a DC motor directly to an AC supply is not recommended and can result in damage to the motor.