GATE EE 2024 | Synchronous Machines Question 2 | Electrical Machines

GATE EE 2024

MCQ (More than One Correct Answer)

-1.33

Which of the following options is/are correct for the Automatic Generation Control (AGC) and Automatic Voltage Regulator (AVR) installed with synchronous generators?

AGC response has a local effect on frequency while AVR response has a global effect on voltage.

AGC response has a global effect on frequency while AVR response has a local effect on voltage.

AGC regulates the field current of the synchronous generator while AVR regulates the generator’s mechanical power input.

AGC regulates the generator’s mechanical power input while AVR regulates the field current of the synchronous generator.

GATE EE 2023

Numerical

-0.67

A three-phase synchronous motor with synchronous impedance of 0.1+j0.3 per unit per phase has a static stability limit of 2.5 per unit. The corresponding excitation voltage in per unit is _________ (Round off to 2 decimal places).

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GATE EE 2022

Numerical

-0.67

A star-connected 3-phase, 400 V, 50 kVA, 50 Hz synchronous motor has a synchronous reactance of 1 ohm per phase with negligible armature resistance. The shaft load on the motor is 10 kW while the power factor is 0.8 leading. The loss in the motor is 2 kW. The magnitude of the per phase excitation emf of the motor, in volts, is ________. (round off to nearest integer).

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GATE EE 2017 Set 1

Numerical

-0

Two parallel connected, three-phase, $$50Hz,$$ $$11kV,$$ star-connected synchronous machines $$A$$ and $$B,$$ are operating as synchronous condensers. They together supply $$50$$ $$MVAR$$ to a $$11$$ $$kV$$ grid. Current supplied by both the machines are equal. Synchronous reactances of machine $$A$$ and machine $$B$$ are $$1\,\,\Omega $$ and $$3\,\,\Omega ,$$ respectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine $$A$$ to that of machine $$B$$ is ____________. (Give the answer up to two decimal places).

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