COUPLING-PERMANENT 1242138 - Caterpillar

This section applies to engines equipped with junction boxes.Shutoff and alarm systems are either electrically or mechanically operated. The operation of all electric shutoffs and alarms utilize components which actuate switches in a sensing unit.Sensing switches are set at critical operating temperature, pressure, level or speed than the alarm components. More critical settings protect the engine from damage.A shutoff switch opens or closes the circuit to the fuel shutoff solenoid. Opening the circuit to the fuel shutoff solenoid moves the fuel rack to the fuel OFF position. The particular shutoff may require resetting before the engine will start.When any sensing switch shuts the engine down, the problem causing the shutdown must be corrected before attempting to restart the engine.Familiarize yourself with the* types and locations of the shutoff controls* conditions which cause each control to function* resetting procedure required to restart your engineManually or mechanically operated systems require resetting by pushing the RESET button until it latches. After the engine is started, oil pressure will activate the RESET button to the extended running position.
If the RESET button does not move to the extended position after the engine starts, the engine will NOT be protected by this particular switch.If the RESET button remains in the reset position, the engine oil pump will not develop normal oil pressure. An inspection should be made to correct the problem.
Automatic START/STOP systems use oil pressure to automatically reset.The Engine Protective Devices shutdown controls should be tested every 1000 service hours by authorized personnel.Emergency Stop Push Button
Emergency Stop Push Button (ESPB)The Emergency Stop Push Button (ESPB) requires resetting both the push button and the air inlet shutoff (if equipped) before the engine will start.
Always determine the cause of the engine shutdown. Make necessary repairs before attempting restarting the engine.Emergency shutoff controls are for EMERGENCY use ONLY. DO NOT use Emergency shutoff devices or controls for normal stopping procedure. Refer to the Engine Stopping section of this manual for normal stopping procedures.
Oil Pressure Switch
Typical example of oil pressure switches, mounted in the rear of the junction box.An oil pressure switch has wires connected to the electrical shutoff system for alarm or shutdown functions. The oil pressure switch senses oil pressure at the bearing oil gallery. Switches may close at 48 to 62 kPa (7 to 9 psi) below actual trip point. No resetting procedure is required.Water Temperature Contactor Switch
This contactor switch is a coolant temperature sensor.The water temperature contactor switch is located near the coolant water regulator housing. Excessive water temperature closes the switch. Maximum coolant temperature to trip shutoff is 104°C (219°F). The switch opens as the coolant cools. No resetting procedure is required. The unit has wires connected to the electrical shutoff system for alarm or shutdown functions.
The sensing element must be submerged in the coolant to operate. Be sure to have an adequate water supply in the jacket water system, or engine damage could result.
Coolant Loss Sensor (If Equipped)
The optional coolant loss sensor is usually mounted near the top of the