A three-phase, 12 pole induction motor is excited by a 60 Hz three-phase source. At rated load and speed, the induction motor runs at 860 rpm and absorb 90kW power from the three-phase AC input. The kinetic energy of all revolving parts is 100kJ at rated load and speed.
a. Calculate the slip of the motor at rated speed.
b. If the voltage induced at the rotor bar is 10V when the rotor is locked, what is the voltage induced at the rotor bar when the motor is at rated speed?
c. What is the I^2R loss at rated load and speed?
d. Plugging is applied to stop the induction motor and then reverse the rotation to 860 rpm, how much power dissipated in the rotor circuit during this process?