SHOE-TRACK 1Q4744 - Caterpillar

When jump starting an engine, the instructions in the Operation and Maintenance Manual, "Starting with Jump Start Cables" should be followed in order to properly start the engine.This engine may be equipped with a 12 volt starting system or with a 24 volt starting system. Only equal voltage for boost starting should be used. The use of a welder or of a higher voltage will damage the electrical system.
The engine has several input components which are electronic. These components require an operating voltage.This engine is tolerant of common external sources of electrical noise. Electromechanical buzzers can cause disruptions in the power supply. If electromechanical buzzers are used near the vehicle, the engine electronics should be powered directly from the battery system through a dedicated relay. The engine electronics should not be powered through a common power bus with other devices that are activated by the keyswitch.Engine Electrical System
The electrical system can have three separate circuits. The three circuits are the charging circuit, the starting circuit, and the low amperage circuit. Some of the electrical system components are used in more than one circuit.The charging circuit is in operation when the engine is running. An alternator creates electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output in order to maintain the battery at full charge.The starting circuit is in operation when the start switch is activated.The low amperage circuit and the charging circuit are connected through the ammeter. The starting circuit is not connected through the ammeter.Charging System Components
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. The magnetic poles are similar to fingers. An air space exists between each opposite pole. 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.