A three-phase, 4-pole, 50 Hz induction motor runs at 1425 rpm. Find out the percentage slip of the induction motor.

• A. 6%
• B. 5%
• C. 4%
• D. 3%

Answer: (B)

Slip, s = (Ns - Nr)/Ns
Ns = 120f/P
Ns = 1500 rpm

s = (1500 - 1425)/1500
s = 0.05
%s = 5%