The Rotor of a 4 pole, 50hz slip ring induction motor has a resistance of 5ohm per phase and inductance of 150mH per phase. Calculate the slip speed at which max torque occurs.
I have used Ns = 120f/p to find the synchronous speed, being 1500RPM, but I cannot calculate the Slip speed without knowing the rated RPM of the motor.
Is there a way to calculate this using the given information?
UPDATE: I believe this is the answer.
ns = 120f/p
= 1500 rpm
fr = X/2piL
= 5/(2pi x 0.150)
= 5.3hz (or rpm?)
Slip% = fr/f
Slip speed = slip% x ns
= 0.106 x 1500
= 159rpm at 10.6% slip (0.106x100)