Alarms and shutoffs are electronically controlled. The operation of all alarms and shutoffs utilize components which are actuated by a sensing unit. The alarms and shutoffs are set at critical operating temperatures, pressures, or speeds in order to protect the engine from damage.
The alarms function in order to warn the operator when an abnormal operating condition occurs. The shutoffs function in order to shut down the engine when a more critical abnormal operating condition occurs. The shutoffs help to prevent damage to the engine.
Shutoffs may cause unburned gas to remain in the air inlet and in the exhaust manifold.
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Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or property damage may result. Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to the topic on purging unburned gas in the "Starting the Engine" section. |
If an engine protective device shuts off the engine, always determine the cause of the shutoff. Make the necessary repairs before attempting to start the engine.
Become familiar with the following information:
- Types of the alarm and shutoff controls
- Locations of the alarm and shutoff controls
- Conditions which cause each control to function
- Resetting procedure that is required before starting the engine
Alarms must function properly in order to provide timely warning to the operator. Shutoffs help to prevent damage to the engine. It is impossible to determine if the engine protective devices are in good working order during normal operation. Malfunctions must be simulated in order to test the engine protective devices.
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During testing, abnormal operating conditions must be simulated. The tests must be performed correctly in order to prevent possible damage to the engine. |
Periodic testing of engine protective devices for proper operation is recommended maintenance. To prevent damage to the engine, only authorized service personnel or your Caterpillar dealer should perform the tests.
Engines Without A Caterpillar Remote Control Panel (Status)
The customer must provide the relay logic for engines that are not equipped with a Caterpillar Remote Control Panel (Status). The customer must provide the relay logic for the following parameters:
- Oil pressure (high idle limit)
- Oil pressure (low idle limit)
- Jacket water coolant temperature (high temperature)
- Overspeed
The specific limits are listed in Table 1. Relay logic must be provided for shutting off the engine in case any of the limits are reached. Consult your Caterpillar dealer for assistance.
| G3406 Engine Shutdown Setpoints | ||||
| Rated RPM | Minimum Oil Pressure | Jacket Water(1)
Temp. |
Overspeed RPM | |
| High Idle RPM | Low Idle RPM | |||
| 1000 | |
|
|
1200 |
| 1400 | |
|
|
1680 |
| 1500 | |
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|
1800 |
| 1800 | |
|
|
2160 |
| (1) | To prevent overheating, the coolant pressure must be a minimum of |