Electrical Engineering GATE 2014 Set-3 Questions with Answer

Ques 14 Electrical Machines

The torque-speed characteristics of motor (T_M) and load (T_L) for two cases are shown in the figures (a) and (b). The load torque is equal to motor torque at points P, Q, R and S

Ques 15 Electrical Machines

An open circuit test is performed on 50 Hz transformer, using variable frequency source and keeping V/f ratio constant, to separate its eddy current and hysteresis losses. The variation of core loss/frequency as function of frequency is shown in the figure

Ques 16 Electrical Machines

A non-salient pole synchronous generator having synchronous reactance of 0.8 pu is supplying 1 pu power to a unity power factor load at a terminal voltage of 1.1 pu. Neglecting the armature resistance, the angle of the voltage behind the synchronous reactance with respect to the angle of the terminal voltage in degrees is ________.

Ques 17 Electrical Machines

A separately excited 300 V DC shunt motor under no load runs at 900 rpm drawing an armature current of 2 A. The armature resistance is 0.5 Ω and leakage inductance is 0.01 H. When loaded, the armature current is 15 A. Then the speed in rpm is ________.

Ques 18 Electrical Machines

The parameters measured for a 220V/110V, 50 Hz, single-phase transformer are:
Self inductance of primary winding = 45 mH
Self inductance of secondary winding = 30 mH
Mutual inductance between primary and secondary windings = 20 mH
Using the above parameters, the leakage (L_l1, L_l2) and magnetizing (L_m) inductances as referred to primary side in the equivalent circuit respectively, are

Ques 19 Electrical Measurements

An LPF wattmeter of power factor 0.2 is having three voltage settings 300 V, 150 V and 75 V, and two current settings 5 A and 10 A. The full scale reading is 150. If the wattmeter is used with 150 V voltage setting and 10 A current setting, the multiplying factor of the wattmeter is ________.

Ques 20 Electrical Measurements

The two signals S1 and S2, shown in figure, are applied to Y and X deflection plates of an oscilloscope.

Ques 21 Electromagnetics

A hollow metallic sphere of radius r is kept at potential of 1 Volt. The total electric flux coming out of the concentric spherical surface of radius R(>r) is

Ques 22 Electromagnetics

A perfectly conducting metal plate is placed in x-y plane in a right handed coordinate system. A charge of +32πε_o√2 columbs is placed at coordinate (0, 0, 2). ε_o is the permittivity of free space. Assume î, ĵ, k̂ to be unit vectors along x, y and z axes respectively. At the coordinate (√2,√2,0), the electric field vector E (Newtons/Columb) will be

Ques 23 Engineering Mathematics

Two matrices A and B are given below:

Ques 24 Engineering Mathematics

A particle, starting from origin at t=0 s, is traveling along x-axis with velocity
v = (π/2)cos((π/2)t)m/s
At t = 3 s, the difference between the distance covered by the particle and the magnitude of displacement from the origin is ________.

Ques 25 Engineering Mathematics

Let ∇·(fv) = x²y+y²z+z²x, where f and v are scalar and vector fields respectively. If v = yi+zj+xk, then v·∇f is

Ques 26 Engineering Mathematics

Lifetime of an electric bulb is a random variable with density f(x)=kx², where x is measured in years. If the minimum and maximum lifetimes of bulb are 1 and 2 years respectively, then the value of k is ________.