Consider a 6 pole, Y connected, 3 phase 400 V, 50 Hz induction motor, that gives the following readings after performing the No load and the Blocked rotor test.
No load test: 400 V, 7.5 A, 701.4806 W
Blocked rotor test: 150 V, 35 A, 4001.0373 W
The per phase stator resistance is 0.545 Ω. The ratio of stator leakage reactance to the reflected rotor leakage reactance is 2:1. At full load the induction motor is running at 960 rpm.
a) Determine the per phase stator leakage reactance, magnetizing reactance and standstill rotor leakage reactance reflected to stator (in Ω).
b) Determine the per phase rotor resistance reflected to stator (in Ω).
c) Considering the rotor circuit as load, determine the per phase Thevenin voltage (in V) and per phase Thevenin impedance (in Ω). Also draw the per phase Thevenin's equivalent circuit at full load, mentioning all the circuit parameters.
d) Determine the net rotational loss of the induction motor (in W).
e) Determine the net mechanical power output (in W) of the induction motor at full load.
f) Determine the efficiency (in %) of the induction motor at full load condition.
