MGVCL Exam Paper (30-07-2021 Shift 2)
A three-phase 400 V, 6-pole, 50 Hz squirrel-cage induction motor is running at a slip of 5%. The speed of rotor with respect to stator magnetic field and speed of the stator magnetic field with respect to rotor magnetic field are

950 rpm, 1000 rpm
-50 rpm, 1000 rpm
950 rpm, zero
-50 rpm, zero

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
The voltage applied to a transformer primary is increased keeping V/f constant. With this, the core loss ____ and the magnetizing current (Im) ____

remains constant, decreases
increases, increases
increases, remains constant
decreases, increases

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
A 50 Hz synchronous generator is connected to an infinite bus through a line. The p.u. reactances of generator and the line are j0.3 p.u. and j0.2 p.u. respectively. The generator no load voltage is 1.1 p.u. and that of infinite bus is 1.0 p.u. The inertia constant of the generator is 4 MW-sec/MVA. Determine the frequency of natural oscillations if the generator is loaded to 60% of its maximum power transfer capacity and small perturbation in power is given.

1.42 Hz
1.52 Hz
1.32 Hz
1.62 Hz

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
The expression for voltage regulation of a short transmission line for leading power factor is given by: ____, where, 'I' is the line current, 'V_r' is the receiving end voltage, 'R' is the line resitance and 'X' is the line reactance.

(IRcosφ_r + IXsinφ_r)/V_r
(IRcosφ_r - IXsinφ_r)/V_r
(IXcosφ_r + IRsinφ_r)/V_r
(IXcosφ_r - IRsinφ_r)/V_r

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP

MGVCL Exam Paper (30-07-2021 Shift 2)
Interposing current-transformer (CT) is used in differential protection of a transformer to

increase the sensitivity of the relay
match the standard ratio of CTs used on both sides of the transformer winding
minimize the effect of saturation of the main CTs
limit the main CT secondary current

ANSWER EXPLANATION DOWNLOAD EXAMIANS APP
MORE MCQ ON MGVCL Exam Paper (30-07-2021 Shift 2)