DOOR ASSEM. 9D1646 - Caterpillar

The alternator should never be operated without the battery in the circuit. The making or the breaking of an alternator connection with a heavy load on the circuit can cause damage to the regulator.
Alternator
The alternator is driven by the crankshaft pulley through a belt that is a Poly-vee type. This alternator is a three-phase self-rectifying charging unit. The regulator is part of the alternator.The alternator design has no need for slip rings or for brushes. The only part of this alternator that moves is the rotor assembly. All of the conductors that carry current are stationary. The following components are the conductors: the field winding, the stator windings, six rectifying diodes and the regulator circuit.The rotor assembly has many magnetic poles with air space between each of the opposite poles. The poles have residual magnetism that produces a small amount of magnet-like lines of force (magnetic field). This magnetic field is produced 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 in the stator windings. The alternating current is produced from the small magnetic lines of force that are created by the residual magnetism of the poles. The AC is changed into Direct Current (DC) when the current passes through the diodes of the rectifier bridge. Most of this current provides the battery charge and the supply for the low amperage circuit. The remainder of current is sent to the field windings. The DC current flow through the field windings (wires around an iron core) increases the strength of the magnetic lines of force. These stronger magnetic lines of force increase the amount of AC that is produced in the stator windings. The increased speed of the rotor assembly also increases the current output of the alternator and the voltage output of the alternator.The voltage regulator is a solid-state electronic switch. The voltage regulator senses the voltage of the system. The regulator then uses switches to control the current to the field windings. This controls the voltage output in order to meet the electrical demand of the system.