Question

Breakdown torque in a 3-phase induction motor of negligible stator impedance is:

• A. Directly proportional to rotor resistance
• B. Inversely proportional to rotor resistance
• C. Directly proportional to rotor leakage reactance
• D. Inversely proportional to rotor leakage reactance

Hint:

Breakdown torque in an induction motor is inversely proportional to the rotor leakage reactance. A higher reactance leads to a lower breakdown torque.

Answer 1

The Correct Option is D

In a 3-phase induction motor, the breakdown torque is inversely proportional to the rotor leakage reactance. The breakdown torque is the torque at which the motor starts to break down due to excessive slip. When the rotor leakage reactance increases, the breakdown torque decreases, and vice versa. This is why it is inversely proportional to rotor leakage reactance.
Thus, the correct answer is inversely proportional to rotor leakage reactance.