GATE EE 2025 Set 1 — Question 28

MSQ+1 / -0MediumParallel OperationSynchronous MachinesElectrical Machines

Electrical Machines → Synchronous Machines → Parallel Operation

Last updated 5 September 2026

Question

Instrument(s) required to synchronize an alternator to the grid is/are

Correct answer (A) Voltmeter; (C) Synchroscope Solution To synchronize an alternator with an infinite bus (grid), the following conditions must be satisfied: 1. Voltage Magnitude: The terminal voltage of the incoming alternator must be equal to the grid voltage. This is checked using a Voltmeter . 2. Frequency: The frequency of the alternator must be equal to (or slightly higher than) the grid frequency. 3. Phase Sequence: The phase sequence of the alternator must be the same as that of the grid. 4. Phase Angle: The phase displacement between the corresponding phases must be zero. A Synchroscope is specifically designed to indicate the frequency difference and the phase angle between the incoming machine and the grid. Therefore, both a Voltmeter and a Synchroscope are essential instruments for the synchronization process. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Voltmeter; (C) Synchroscope Solution To synchronize an alternator with an infinite bus (grid), the following conditions must be satisfied: 1. Voltage Magnitude: The terminal voltage of the incoming alternator must be equal to the grid voltage. This is checked using a Voltmeter . 2. Frequency: The frequency of the alternator must be equal to (or slightly higher than) the grid frequency. 3. Phase Sequence: The phase sequence of the alternator must be the same as that of the grid. 4. Phase Angle: The phase displacement between the corresponding phases must be zero. A Synchroscope is specifically designed to indicate the frequency difference and the phase angle between the incoming machine and the grid. Therefore, both a Voltmeter and a Synchroscope are essential instruments for the synchronization process.

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