Which of the following is required for synchronizing alternators?

For successful synchronization of alternators, it is essential that their frequencies are equal. Synchronization involves connecting multiple generators together so that they can operate in parallel without causing instability in the power grid. If the frequencies of the alternators differ, it can lead to severe electrical disturbances, including transients and oscillations, which can disrupt the system and potentially damage the equipment.

When the frequencies match, the alternators can share the load effectively and operate together seamlessly. This is a fundamental requirement for any synchronization process in electrical power systems, ensuring that the generators work harmoniously rather than fighting against each other.

Other aspects, such as phase rotations and voltages, also play a role in synchronization, but the equality of frequencies is a prerequisite that must be met before addressing those factors. Thus, ensuring that the frequencies of the alternators are equal is foundational to the synchronization process.