The equivalent circuit values of a certain power transformer are given in the table below:
Parameter Value
Power rating 2 kVA
Primary : secondary voltages, V 230 : 115
Primary leakage reactance, X1 0.43
Secondary leakage reactance, X2 0.06
Primary ohmic resistance, R1 0.5
Secondary ohmic resistance, R2 0.12
(i) If the secondary terminal is shorted, determine the transformer impedance as measured from the primary side.
(ii) If the primary terminal is shorted, determine the transformer impedance as measured from the secondary side.
(iii) The primary terminal is connected to a 220V voltage source and the secondary terminal is connected to a 6.5Ω resistive load. Determine the active and reactive power supplied by the source.
(b) A 220 V, three-phase, two-pole, 50 Hz induction motor is running at a slip of 5 percent and draws 50 kW. Electrical losses are 2 kW and mechanical losses are 1 kW.
(i) Determine the speed of the magnetic fields in revolutions per minute.
(ii) Determine the speed of the rotor in revolutions per minute.
(iii) Determine the rotor frequency in hertz.
(iv) Determine the load torque.