BOLT 8T4177 - Caterpillar

Engine Electrical System
Illustration 1 g01228806
Circuit diagram for electrical systemThe electrical system has two separate circuits.
Charging circuit
Starting circuitSome of the electrical system components are used in more than one circuit. The following items are common in each of the circuits:
Battery
Circuit breaker
Cables
Wires for the batteryThe charging circuit is in operation when the engine is running. An alternator converts mechanical energy to electrical energy 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 equipped, must be in the ON position in order to let the electrical system function. There will be damage to some of the charging circuit components if the engine is running with the disconnect switch 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.Electronic Control System
This engine uses an electronic controller in order to control the engine speed. The electronic controller controls the engine speed within 0.25% of the desired speed. If the electronic controller cannot control the engine speed, a mechanical controller will limit the engine speed to 2050 rpm.The first part of the electronic control system is the electronic controller. The controller can be set by using 237-9074 Speed Control Calibration Gp . The second part of the electronic control system is the mechanical actuator. The actuator is attached to the fuel injection pump in order to control the amount of fuel that is injected. The third part of the electronic control system is the speed sensor. The speed sensor is attached to the flywheel housing. The speed sensor measures the speed of the flywheel. This information is transmitted to the electronic controller. The speed is used by the electronic controller in order to operate the mechanical actuator.Automatic Shutdown System
Electrical Connector
Illustration 2 g00841411
Connector for the automatic shutdown device (typical example) (1) Ignition switch (red wire) (2) Ignition switch (orange wire) (3) Fuel shutoff solenoid (red and black wire) (4) Engine oil pressure switch (brown wire) (5) Coolant temperature switch (blue wire) (6) Ground (black wire)Automatic Shutdown Conditions
The engine will shut down if the following conditions continue for more than ten seconds while you start the engine or for two seconds while you operate the engine:The automatic shutdown is incorporated into the controller for engine speed.Coolant temperature exceeds the following values: ... 96 ° C 3 ° C (204.80 ° F 5.40 ° F)Engine oil pressure falls below the following value: ... 80 kPa (11.6 psi)High exhaust temperature for the wet exhaust system (only): ... 130 ° C 10 ° C (266 ° F 18 ° F)Note: There is no automatic shutdown for low coolant level.Note: The capacity of the diode must be 3 Amperes with a reverse voltage of 600 volts.Note: The rated current draw of the engine oil pressure switch is 0.42 Amperes (5 watts maximum bulb).Note: