GATE EE 2010 Question Paper (14-Feb-2010) (Shift 1)

A balanced star connected purely resistive load is connected at the secondary of a star delta transformer as shown in the figure.



The line to line voltage rating of the transformer is 110V/220V. neglecting the non-idealities of the transformer, the impedance Z of the equivalent star connected load, referred to the primary side of the transformer is

A balanced three-phase voltage is applied to a star-connected induction motor, the phase to the neutral voltage being V, The stator resistance, rotor resistance referred to as the stator, and stator leakage reactance. rotor leakage reactance referred to the stator, and the magnetizing reactance is denoted by r₁, r₂, x${}_{1.}$ x${}_{2,}$ and Xm respectively. The magnitude of the starting current of the motor is given by:

Consider a three-core, three-phase, 50 Hz, 11 kV cable whose conductors are denoted as R, Y and B in the figure. The inter-phase capacitance (C₁) between each pair of conductors is 0.2 μF and the capacitance between each line conductor and the sheath is 0.4 μF. The per-phase charging current is

If the electrical circuit of figure (b) is an equivalent of the coupled tank system of figure (a), then

The transistor circuit shown uses a ‘Si’ transistor with V${}_{BE}$ = 0.7 V${}_{,}$ I${}_C$ ≈ I${}_E$ and a DC current gain of 100. The value of Vₒ is