Question

What is the frequency of rotor current of a 50Hz induction motor operating at 2% slip?

• A. 50Hz
• B. 100Hz
• C. 2Hz
• D. 1Hz

Hint:

The rotor current frequency is directly proportional to the slip and the supply frequency. It can be calculated using \( f_r = s \times f_s \), where \(s\) is the slip and \(f_s\) is the supply frequency.

Answer 1

The Correct Option is C

The frequency of the rotor current (\(f_r\)) in an induction motor is given by the formula: \[ f_r = s \times f_s \] Where: - \(f_s\) is the supply frequency (50Hz), - \(s\) is the slip. Given that the slip is 2%, or \(s = 0.02\), the rotor frequency is: \[ f_r = 0.02 \times 50 = 1 \, \text{Hz} \] Thus, the frequency of the rotor current is 1Hz, which corresponds to option (4).