GATE EE 2014 Question Paper (01-Mar-2014) (Shift 2)

The core loss of a single phase, 230/115 V, 50Hz power transformer is measured from 230 V side by feeding the primary (230 V side) from a variable voltage variable frequency source while keeping the secondary open circuited. The core loss is measured to be 1050 W for 230 V, 50 Hz input. The core loss is gain measured to be 500 W for 138 V, 30 Hz input. The hysteresis and eddy current losses of the transformer for 230 V, 50 Hz input are respectively

A 15 kW, 230 V dc shunt motor has armature circuit resistance of 0.4 Ω and field circuit resistance of 230 Ω. At no load and rated voltage, the motor runs at 1400 rpm and the line current drawn by the motor is 5.A. At full load, the motor draws a line current of 70 A. Neglect armature reaction. The full load speed of the motor in rpm is______

A 3 phase, 50 Hz, six pole induction motor has a rotor resistance of 0.1 Ω and reactance of 0.5 Ω. Neglect the voltage drop in stator and assume that the rotor resistance is constant. Given that the full load slip is 5%, the ratio of maximum torque to full load torque is approximately equal to

A three phase synchronous generator is to be connected to the infinite bus. The lamps are connected as shown in the figure for the synchronization. The phase sequence of bus voltage is R – Y – B and that of incoming generator voltage is R’ – Y’ – B’.



It was found that the lamps are becoming dark in the sequence Lₐ – L${}_b$ – L${}_c$. It means that the phase sequence of incoming generator is

A distribution feeder of 1 km length having resistance, but negligible reactance, is fed from both the ends by 400 V, 50 Hz balanced sources. Both voltage sources S₁ and S₂ are in phase. The feeder supplies concentrated loads of unity power factor as shown in the figure.



The contributions of S₁ and S₂ in 100 A current supplied at location P respectively, are