SIMPLE ALTERNATORS PRINCIPLES
An alternator
In the next diagram, the two brushes contact two continuous rings, so
the two external terminals are always connected to the same ends of the coil.
The result is the unrectified, sinusoidal emf given by NBAω sin ωt .
This is an AC generator. The advantages of AC and DC
generators are compared in a section below. We saw above that a DC motor
is also a DC generator. Similarly, an alternator is also an AC motor. However,
it is a rather inflexible one.