ELECTRICAL SYSTEM CONTINUED
The rotor assembly has many magnetic poles that look like fingers with air space between each of the opposite
poles. The poles have residual magnetism, which produces a small magnetic field between the poles. As the rotor
assembly begins to turn between the field winding and the stator windings, a small amount of alternating current
(AC) is produced. The AC current is produced in the stator windings from the small magnetic field. The AC current
is changed to direct current (DC) when the AC current passes through the diodes of the rectifier bridge. The
current is used for the following applications:
Charging the battery
Supplying the accessory circuit that has the low amperage
Strengthening the magnetic field
The first two applications use the majority of the current. As the DC current increases through the field windings,
the strength of the magnetic field is increased. As the magnetic field becomes stronger, more AC current is
produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage
The voltage regulator is a solid-state electronic switch, which senses the voltage in the system. The voltage
regulator switches ON and OFF many times per second in order to control the field current for the alternator. The
alternator uses the field current in order to generate the required voltage output.
C AU T I O N
Never operate the alternator without the battery in the circuit. Making or breaking an
alternator connection with heavy load on the circuit can cause damage to the regulator.
Failure to follow this caution may cause damage to equipment.
Figure 2. Alternator Components.
Table 1. Alternator Components.