A voltmeter gives 120 oscillations per minute when connected to the rotor of an induction motor. When the stator frequency is 50 Hz, what is the slip of the motor?
- A. 2%
- B. 2.5%
- C. 4%
- D. 5%
Answer: C. 4%
Explanation: Rotor frequency fr = 120 cycles / 60 s = 2 Hz; slip s = fr/f = 2/50 = 0.04 = 4%.