(Question 1)

A periodic voltage waveform observed on an oscilloscope across a load is shown. A permanent magnet moving coil (PMMC) meter connected across the same load reads

(Question 2)

With initial conditionx(1) = 0.5 , the solution of the differential equation,

tdxdt+x=ttdxdt+x=tis

(Question 3)

In the following figure, C1and C2are ideal capacitors. C1has been charged to 12 V before the ideal switch S is closed att= 0. The currenti(t)for alltis

(Question 4)

The figure shows a two-generator system supplying a load of PD= 40 MW, connected at bus 2. The fuel cost of generators G1 and G2 are :

C1(PG1)=10,000 Rs/MWh andC2(PG2)=12,500 Rs/MWh

and the loss in the line isPloss(pu)=0.5P2G1(pu)Plosspu=0.5PG1pu2,where the loss coefficient is specified in pu on a 100 MVA base. The most economic power generation schedule in MW is

(Question 5)

The sequence components of the fault current are as follows: Ipositive= j1.5 pu, Inegative= -j0.5 pu, Izero= -j1 pu. The type of fault in the system is?

(Question 6)

A half-controlled single-phase bridge rectifier is supplying an R-L load. It is operated at a firing angle and the load current is continuous. The fraction of cycle that the freewheeling diode conducts is?

(Question 7)

For the circuit shown in the figure, the voltage and current expressions arev(t)=E1sin(t)+E3sin(3t)vt=E1sint+E3sin3tandi(t)=I1sin(t1)+I3sin(3t3)+I5sin(5t)it=I1sint-1+I3sin3t-3+I5sin5tThe average power measured by the Wattmeter is?

(Question 8)

For the system shown below, SD1and SD2are complex power demands at bus 1 and bus 2 respectively. If|V2|V2=1 pu , the VAR rating of the capacitor (QG2) connected at bus 2 is?

(Question 9)

A cylindrical rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the infinite bus voltage is 1 pu. The inertia constant of the generator is 5 MW-s/MVA and the generator reactance is 1 pu. The critical clearing angle, in degrees, for a three-phase dead short circuit fault at the generator terminal is?

(Question 10)

In the circuit shown, an ideal switch S is operated at 100 kHz with a duty ratio of 50 %. Given that icis 1.6 A peak-to-peak and I0is 5 A dc, the peak current in S is?

(Question 11)

A 220 V, 15 kW, 1000 rpm shunt motor with armature resistance of 0.25; has a rated line current of 68 A and a rated field current of 2.2 A. The change in field flux required to obtain a speed of 1600 rpm while drawing a line current of 52.8 A and a field current of 1.8 A is?

(Question 12)

The state variable description of an LTI system is given by

x1.x2.x3.=00a3a1000a20x1x2x3+001ux1.x2.x3.=0a1000a2a300x1x2x3+001u

y=(100)x1x2x3y=100x1x2x3

where y is the output and u is the input. The system is controllable for

(Question 13)

An analog voltmeter uses external multiplier settings. With a multiplier setting of 20 k, it reads 440 V and with a multiplier setting of 80 k, it reads 352 V. For a multiplier setting of 40 k, the voltmeter reads?

(Question 14)

The locked rotor current in a 3-phase, star connected 15 kW, 4-pole, 230 V, 50 Hz induction motor at rated conditions is 50 A. Neglecting losses and magnetizing current, the approximate locked rotor line current drawn when the motor is connected to a 236 V, 57 Hz supply is?

(Question 15)

A single phase 10 kVA, 50 Hz transformer with 1 kV primary winding draws 0.5 A and 55 W, at rated voltage and frequency, on no load. A second transformer has a core with all its linear dimensions22times the corresponding dimensions of the first transformer. The core material and lamination thickness are the same in both transformers. The primary windings of both the transformers have the same number of turns. If a rated voltage of 2 kV at 50 Hz is applied to the primary of the second transformer, then the no load current and power, respectively, are?e