An alternator provides maximum power when the load angle is:

Question

Question

This question was previously asked in

ALP CBT 2 Electrician Previous Paper: Held on 22 Jan 2019 Shift 2

Answer 1

An alternator power output is directly proportional to the sine of its load angle.

\(P = \frac{{EV}}{X}sin\theta\)

Where,

P = Power output of the alternator

E = Sending voltage of the alternator

V = Receiving voltage of the alternator

X = Rectance of alternator

θ = Load angle

The maximum power output from the alternator would occur when the load angle is 90 degrees.
But still, the load angle is maintained between 20 and 30 degrees.
This is done to ensure the stability of the power system in which the alternator is connected.
The load angle of 90 degrees is known as the point of critical stability, if the load angle exceeds this value then the alternator will become unstable and its speed can go out of control.
To ensure that this situation never occurs the alternator is always operated at a load angle of 20-30 degrees.