MGVCL Exam Paper (30-07-2021 Shift 1)
If a 415 V, 50 Hz, star-connected, three-phase squirrel-cage induction motor is operated from a 415 V, 70 Hz supply, the torque that the motor can now provide while drawing rated current from the supply

reduces
remains the same
increases or reduces depending upon the rotor resistance
increases

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MGVCL Exam Paper (30-07-2021 Shift 1)
A coil having an inductance of 100 mH is magnetically coupled to another coil having an inductance of 900 mH. The coefficient of coupling between the coils is 0.45. Calculate the equivalent inductance if the two coils are connected in series aiding.

1135 mH
1270 mH
932 mH
730 mH

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MGVCL Exam Paper (30-07-2021 Shift 1)
A single phase motor connected to 400 V, 50 Hz supply takes 30 A at a power factor of 0.7 lagging. Calculate the capacitance required in parallel with the motor to raise the power factor to 0.9 lagging.

79.5 μF
89.5 μF
99.5 μF
69.5 μF

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MGVCL Exam Paper (30-07-2021 Shift 1)
Consider the following two statements and choose the correct answer.
Statement 1: The V-curves of a synchronous motor show relationship between armature current and supply voltage.
Statement 2: The plot of power factor against the field current of synchronous motor is known as inverted V curves.

Both Statement 1 and Statement 2 are TRUE
Both Statement 1 and Statement 2 are FALSE
Statement 1 is TRUE and Statement 2 is FALSE
Statement 1 is FALSE and Statement 2 is TRUE

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MGVCL Exam Paper (30-07-2021 Shift 1)
Simultaneous tripping of the circuit breaker at both ends of a transmission line is achieved by

none of these
pilot protection
distance protection
overcurrent protection

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