Question

If the excitation is critical the power factor of the alternator is

Answer 1

According to the alternator theory, an increase in alternator’s terminal voltage arises from an increase in field excitation. Essentially, the output torque and the load current are held constant. This means that the load is resistive hence there is no VAR output. The load power and load current increases with an increase in terminal voltage. Considering speed as a variable, an increase in load power and a constant output power leads to a fall in speed.