A three phase 12 pole, 220-V, 60- hz ,50 hp squirrel cagemotor , operating at rated load, has a speed of 595 r/min, anefficiency of 89 percent ,and a power factor of 81 percent lagging.The locked rotor current and locked rotor torque at a rated voltage and rated frequency are 725A and 120 percent rated torque,respectivtively. Determine
a) rated line current
b)rated torque
c) minimum voltage required to obtain a blocked- rotor torque equal 70 percent rated torque
d) auto transformer bank ratio required to provide the minimumvoltage in (c)
e)stator current at blocked rotor with auto transformer incircuit;
f) corresponding input current to the transformer when starting the motor at the voltage in (c)