The alternator is cooled by an external fan which is mounted
behind the pulley. The fan pulls air through the holes in the
back of the alternator. The air exits the front of the alternator.
The alternator converts the mechanical energy and the
magnetic energy into alternating current and voltage. This
conversion is done by rotating a direct current electromagnetic
electromagnetic field is generated by electrical current flowing
through a rotor. The stator generates alternating current and
The alternating current is changed to direct current by a three-
phase, full-wave rectifier. Direct current flows to the output
terminal of the alternator. The rectifier has three exciter
diodes. The direct current is used for the charging process.
A solid state regulator is installed on the rear end of the
alternator. Two brushes conduct current through two slip rings.
The current then flows to the rotor field. A capacitor protects
the rectifier from high voltages.
The alternator is connected to the battery through the ignition
switch. Therefore, alternator excitation occurs when the switch
is in the ON position.
Circuit Breaker With Reset Button
Metal disc in the open position
Metal disc in closed position
Battery circuit terminals
Most models have a circuit breaker. The circuit breaker is a
switch that opens the circuit if the current in the electrical
system is higher than the rating of the circuit breaker. The
metal disc (2) is activated by heat. The metal disc has contact
points which complete the electrical circuit through the circuit
breaker. If the current in the electrical system gets too high,
the metal disc will get hot. This heat causes a distortion of the
metal disc. This distortion causes the contact points to open
the circuit. A circuit breaker that is open can be reset when the
metal disc becomes cooler. Push the reset button (1) in order
to close the contact points and reset the circuit breaker.