SEAL-O-RING 5L2727 - Caterpillar

Engine Electrical System
The electrical system has two separate circuits.
the charging circuit
the starting circuitSome of the electrical system components are used in more than one circuit. The following items are common in each of the circuits:
The battery
The circuit breaker
The cables
The wires for the batteryThe charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output in order to keep the battery at full charge.
The disconnect switch, if so equipped, must be in the ON position to let the electrical system function. There will be damage to some of the charging circuit components if the engine runs with the disconnect with in the OFF position.
If the engine has a disconnect switch, the starting circuit can operate only after the disconnect switch is put in the "ON" position.The starting switch is in operation only when the start switch is activated.The charging circuit is connected through the ammeter. The starting circuit is not connected through the ammeter.Charging System Components
The alternator is driven by the crankshaft pulley through a belt that is a Poly-vee type. The alternator is a three-phase self-rectifying charging unit. The regulator is part of the alternator. The operation of the brushless alternator and the brush type alternator follow.
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.
Brushless Alternator
Illustration 1 g00292313
Brushless Alternator (Typical Example) (1) Regulator (2) Roller bearing (3) Stator winding (4) Ball bearing (5) Rectifier bridge (6) Field winding (7) Rotor assembly (8) FanThis 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, rectifying diodes and components of the regulator circuit.The rotor assembly has many magnetic poles that are similar to fingers 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