Question

The frequency of the rotor current of a 50 Hz, 2 pole induction motor is 2 Hz, determine the percentage slip.

• A. 1.2%
• B. 2.4%
• C. 3.8%
• D. 6%

Hint:

Slip in induction motors is an important parameter that helps in evaluating the motor's efficiency and performance.

Answer 1

The Correct Option is B

The slip \( S \) in an induction motor is given by the formula: \[ S = \frac{f_s - f_r}{f_s} \times 100 \] Where: - \( f_s \) is the synchronous frequency, and - \( f_r \) is the rotor frequency. For a 50 Hz, 2-pole motor, the synchronous speed \( N_s \) is: \[ N_s = \frac{120 \times f_s}{P} = \frac{120 \times 50}{2} = 3000 \, \text{rpm}. \] The slip is calculated as: \[ S = \frac{50 - 2}{50} \times 100 = 2.4%. \]