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.
Alarms function in order to warn the operator when an abnormal operating condition occurs. 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 equipment.
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
On G3400 Engines, protective devices are available for the following faults:
- Low oil pressure
- High coolant temperature
- Overspeed
- Low coolant level
Further protection is supplied by an emergency stop button.
Three basic protection systems are available:
- Self-powered shutoff
- Automatic start/stop system
- Customer supplied shutoff
Note: For an energize-to-shutoff system, the gas shutoff valve must be energized to shut off gas to the engine. For an energize-to-run system, the gas shutoff valve must be energized in order to supply gas to the engine.
The self-powered system can be used with an air starting motor or an electric starting motor. An energize-to-shutoff gas valve and an instrument panel are required for this system.
Power for the automatic start/stop system is supplied by an external 24 volt electrical source. The automatic start/stop system can be used with an air starting motor or an electric starting motor. An energize-to-run gas valve and one of these controls are required:
- Automatic start/stop switchgear
- Engine control logic
For the customer supplied shutoff system, the customer must supply all of the wiring and the shutoffs. This includes the emergency stop button and wiring.
The features of the shutoff systems are listed in Table 1.
| G3400 Engine Protection Systems | ||||
| Item | Type of System | Shut Down Setting Limits | ||
| Self-Powered | Automatic Start/Stop | Customer Supplied (1) | ||
| High jacket water coolant temperature | Yes | Yes | Yes | |
| Low oil pressure (high rpm) | Yes | Yes | Yes | |
| Low oil pressure (low rpm) | |
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| Overspeed (1800 rpm) | No (2) | Yes | Yes | 2160 RPM |
| Overspeed (1400 rpm) | 1680 RPM | |||
| High inlet manifold air temperature
|
No | No | Yes (3) | |
| High inlet manifold air temperature
|
|
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| Emergency stop | Yes | Yes | Yes | N/A |
| (1) | The customer is responsible for supplying the shutoffs and the wiring. |
| (2) | Overspeed protection is available as an option. |
| (3) | The customer is responsible for supplying the protection for either high inlet manifold temperature or high aftercooler water temperature. |