The correct answer is: C. Both (A) and (B)
When the voltage applied to a synchronous motor is increased, the stator flux will increase. This is because the stator flux is proportional to the applied voltage. The increased stator flux will cause the rotor to turn at a higher speed. This is because the rotor is trying to align itself with the stator flux. The increased speed of the rotor will cause the pull-in torque to decrease. This is because the pull-in torque is proportional to the square of the rotor speed.
Here is a more detailed explanation of each option:
- Option A: Stator flux
The stator flux is the magnetic field produced by the stator windings. The stator flux is proportional to the applied voltage. When the voltage applied to a synchronous motor is increased, the stator flux will increase.
- Option B: Pull in torque
The pull-in torque is the torque that is required to start a synchronous motor. The pull-in torque is proportional to the square of the rotor speed. When the voltage applied to a synchronous motor is increased, the rotor speed will increase. This will cause the pull-in torque to decrease.
- Option C: Both (A) and (B)
When the voltage applied to a synchronous motor is increased, the stator flux will increase. This is because the stator flux is proportional to the applied voltage. The increased stator flux will cause the rotor to turn at a higher speed. This is because the rotor is trying to align itself with the stator flux. The increased speed of the rotor will cause the pull-in torque to decrease. This is because the pull-in torque is proportional to the square of the rotor speed.