Two generators are running in parallel. One of the generators may run as a motor for which of the following reasons?

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Question

Two generators are running in parallel. One of the generators may run as a motor for which of the following reasons?

(a) The direction of that generator is reversed

(b) The speed of that generator is increased

(c) The field of that generator is weakened

(d) That generator takes a large share of loads

Answer

The answer is option d. That generator takes a large share of loads

Explanation /Solution

As the other one operates as an excitation motor, as more excitation is required for the first generator.

At the beginning, when in parallel operation, they will have equal speed and the same terminal voltages.

if the second generator load share increase means, the first generator load decrease.

Then Generator 1 speed increases and generated emf increases..

e.m.f for G1 is more than G2, then current flows from G1 to G2. So G2 behaves as a motor as it is consuming the power of G1 instead of Generating power.

What is the Parallel Operation of Alternators?


The operation of connecting an alternator in parallel with another alternator or with common bus bars is known as parallel operation or synchronizing.

Generally, alternators are used in a power system where they are in parallel with many other alternators.

It means that the alternator is connected to a live system of constant voltage and constant frequency.

Often the electrical system to which the alternator is connected, has already so many alternators and loads connected to it that no matter what power is delivered by the incoming alternator, the voltage and frequency of the system remain the same.

In that case, the alternator is said to be connected to infinite bus-bars.

click here to read for on parallel operation of alternators.

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