Electrical Engineering GATE 2017 Set II Questions with Answer

Ques 14 Electrical Machines

A 220 V, 10 kW, 900 rpm separately excited DC motor has an armature resistance R_a=0.02 Ω. When the motor operates at rated speed and with rated terminal voltage, the electromagnetic torque developed by the motor is 70 Nm. Neglecting the rotational losses of the machine, the current drawn by the motor from the 220 V supply is

Ques 15 Electrical Machines

A 120 V DC shunt motor takes 2 A at no load. It takes 7 A on full load while running at 1200 rpm. The armature resistance is 0.8 Ω, and the shunt field resistance is 240 Ω. The no load speed, in rpm, is ________.

Ques 16 Electrical Machines

A star-connected, 12.5kW, 208 V (line), 3-phase, 60 Hz squirrel cage induction motor has following equivalent circuit parameters per phase referred to the stator: R₁=0.3Ω, R₂=0.3Ω, X₁=0.41Ω, X₂=0.41Ω. Neglect shunt branch in the equivalent circuit. The starting current (in Ampere) for this motor when connected to an 80 V (line), 20 Hz, 3-phase AC source is ________.

Ques 17 Electrical Machines

A 25 kVA, 400 V, Δ-connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is ________.

Ques 18 Electrical Machines

If the primary line voltage rating is 3.3 kV (Y side) of a 25 kVA, Y-Δ transformer (the per phase turns ratio is 5:1), then the line current rating of the secondary side (in Ampere) is ________.

Ques 19 Electrical Measurements

A 4 1/2 digit timer counter possesses a base clock of frequency 100 MHz. When measuring a particular input, the reading obtained is the same in: (i) Frequency mode of operation with a gating time of one second and (ii) Period mode of operation (in the x 10 ns scale). The frequency of the unknown input (reading obtained) in Hz is ________.

Ques 20 Engineering Mathematics

Assume that in a traffic junction, the cycle of the traffic signal lights is 2 minutes of green (vehicle does not stop) and 3 minutes of red (vehicle stops). Consider that the arrival time of vehicles at the junction is uniformly distributed over 5 minute cycle. The expected waiting time (in minutes) for the vehicle at the junction is ________.

Ques 21 Engineering Mathematics

Consider a function f(x,y,z) given by f(x,y,z) = (x²+y²-2z²)(y²+z²). The partial derivative of this function with respect to x at the point, x=2, y=1 and z=3 is ________.

Ques 22 Engineering Mathematics

Let x and y be integers satisfying the following equations
2x²+y²=34
x+2y=11
The value of (x+y) is ________.

Ques 23 Engineering Mathematics

Let y²-2y+1=x and √x+y=5. The value of x+√y equals ________. (Give the answer up to three decimal places)

Ques 24 Engineering Mathematics

Let g(x) = {-x, x≤1; x+1, x≥1} and f(x) = {1-x, x≤0; x², x>0}. Consider the composition of f and g i.e., (f o g)(x) = f(g(x)). The number of discontinuities in (f o g)(x) present in the interval (-∞, 0) is:

Ques 25 Engineering Mathematics

The value of the contour integral in the complex-plane

Ques 26 Engineering Mathematics

The eigenvalues of the matrix given below are