If the engine speed drops below the "Engine Underspeed Threshold" setpoint value, the underspeed timer will begin timing. When the timer expires, the "Engine Underspeed" event is made active (if the engine speed has been below the threshold level continuously while timing). If the engine speed rises above the engine underspeed threshold, the "Engine Underspeed" event will be made inactive and the timer will be reset.
If an underspeed condition is detected, "ENGINE UNDERSPEED SHUTDOWN" or "ENGINE UNDERSPEED WARNING" will be displayed on the EMCP 4. These messages are to inform the operator of an underspeed condition.
Note: The severity of the underspeed condition will determine if a warning or shutdown event occurs.
Conditions Which Generate This Code:
The code for engine underspeed is generated when the EMCP 4 determines that an engine underspeed condition has occurred.
Test Step 1. TALK TO THE OPERATOR
- Determine the conditions that caused the underspeed condition.
Expected Result:
An underspeed was caused by an occurrence known to the operator. The operator would like to place the generator set back into service.
Results:
- OK - The operator can determine the cause for the underspeed condition. The condition has been repaired and the operator wants to place the generator set back into service.
Repair: Reset the generator set. Resume normal operation and verify that the problem has been corrected.
The generator set operates normally.
- NOT OK - The underspeed condition was not caused by an occurrence known to the operator. Proceed to Test Step 2
Test Step 2. CHECK THE SETPOINTS.
- View the "Engine Speed Monitor" and "Number of Poles and Generator Frequency" setpoints. Make a note of the setpoints. Refer to Testing and Adjusting, "Electronic Control Module (Generator Set) - Configure". Compare the setpoints against the default setpoints of the particular generator set.
Expected Result:
The setpoints are correct.
Results:
- OK - The setpoints are correct for your particular generator set. Proceed to Test Step 3 for EUI engines. Proceed to Test Step 4 for MUI engines
- NOT OK - The setpoints are NOT correct.
Repair: Reprogram the setpoints. Reset the generator set. Resume normal operation and verify that the problem has been corrected.
STOP
Test Step 3. VERIFY ENGINE SPEED CAN BE VIEWED AND ADJUSTED FROM THE EMCP 4 (EUI ENGINES WHERE ADEM IS SET TO CAN)
Verify that the engine speed can be viewed and adjusted from the EMCP 4 display screen.
Expected Result:
The engine speed can be viewed and adjusted from the EMCP 4 display screen.
Results:
- OK - The engine speed can be viewed and adjusted from the EMCP 4 display screen.
Repair: Adjust the engine speed to meet site requirements. Resume normal operation and verify that the problem has been corrected.
STOP
- NOT OK - The engine speed cannot be adjusted. Proceed to Test Step 7
- NOT OK - The engine speed reads zero on the EMCP 4 display screen.
Repair: The engine speed sensor may have failed or needs adjustment. See Testing and Adjusting, "Speed Sensor (Engine) - Adjust". If the problem remains, replace the engine speed sensor.
STOP
Test Step 4. CHECK THE SYSTEM BY USING THE SPEED POTENTIOMETER (MUI ENGINES ONLY)
- With the engine running, adjust the speed of the engine by turning the speed potentiometer.
Expected Result:
The engine can be adjusted to the desired speed.
Results:
- OK - The engine speed can be adjusted.
Repair: Adjust the engine speed to meet site requirements. Resume normal operation and verify that the problem has been corrected.
STOP
- NOT OK - The engine speed cannot be adjusted with the speed potentiometer. Proceed to Test Step 5
Test Step 5. CHECK THE RESISTANCE OF THE ENGINE SPEED POTENTIOMETER (MUI ENGINES ONLY)
- Shut down the engine.
- Disconnect the speed potentiometer from the governor.
- At the speed potentiometer, measure the resistance of the speed potentiometer.
Expected Result:
The resistance should be adjustable between 0 and 100 ohms.
Results:
- OK - The resistance of the sensor is correct. Proceed to Test Step 6.
- NOT OK - The resistance of the speed potentiometer is not correct.
Repair: Replace the speed potentiometer. Resume normal operation and verify that the problem has been corrected.
STOP
Test Step 6. CHECK THE SPEED POTENTIOMETER HARNESS FOR AN OPEN CIRCUIT (MUI ENGINES ONLY)
- Disconnect the speed potentiometer harness from the governor.
- Check for an open circuit. Check the resistance from the wire connected to terminal 11 of the 2301A governor to the same wire number at the speed potentiometer. The resistance should be 5 ohms or less.
- Check for an open circuit. Check the resistance from the wire connected to terminal 12 of the 2301A governor to the same wire number at the speed potentiometer. The resistance should be 5 ohms or less
Expected Result:
When the resistance is measured between the wire connected to terminal 11 of the 2301A governor to the same wire number at the speed potentiometer connector, the resistance should be 5 ohms or less.
When the resistance is measured between the wire connected to terminal 12 of the 2301A governor to the same wire number at the speed potentiometer connector, the resistance should be 5 ohms or less.
Results:
- OK - The harness functions properly.
Repair: The EMCP 4 may have failed. It is unlikely that the EMCP 4 has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the EMCP 4. Refer to Testing and Adjusting, " Electronic Control Module (Generator Set) - Replace".
STOP
- NOT OK - The harness wiring with the incorrect resistance measurement has failed.
Repair: Replace the failed harness from the 2301A governor to the speed potentiometer or repair the failed harness from the 2301A governor to the speed potentiometer. Resume normal operation and verify that the problem has been corrected.
STOP
Test Step 7. CHECK THE CAN DATA LINK BETWEEN THE EMCP 4 AND THE ENGINE ECM (EUI ENGINES ONLY)
Refer to the Electrical System Schematic for the generator set. Check the data link wiring between the EMCP 4 and the engine ECM. For more information on troubleshooting the data link, Refer to Troubleshooting, "Data Link Circuit Fault".
Results:
- OK - The CAN data link wiring is correct.
Repair: The EMCP 4 may have failed. It is unlikely that the EMCP 4 has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the EMCP 4. Refer to Testing and Adjusting, " Electronic Control Module (Generator Set) - Replace".
STOP
- NOT OK - The wiring is not correct
Repair: Repair the data link wiring or replace the data link wiring. Resume normal operation and verify that the problem has been corrected.
STOP