3-15
Figure 3-12.—Frequency regulation.
VOLTAGE REGULATION
As we have seen before, when the load on a generator is changed, the terminal voltage varies. The
amount of variation depends on the design of the generator.
The voltage regulation of an alternator is the change of voltage from full load to no load, expressed
as a percentage of full-load volts, when the speed and dc field current are held constant.
Assume the no-load voltage of an alternator is 250 volts and the full-load voltage is 220 volts. The
percent of regulation is
Remember, the lower the percent of regulation, the better it is in most applications.
Q19. The variation in output voltage as the load changes is referred to as what? How is it expressed?
PRINCIPLES OF AC VOLTAGE CONTROL
In an alternator, an alternating voltage is induced in the armature windings when magnetic fields of
alternating polarity are passed across these windings. The amount of voltage induced in the windings
