LUG 3S6191 - Caterpillar

System Operation Description:If the voltage drops below the "Generator Undervoltage Percentage Threshold" or the "Automatic Voltage Regulator (AVR) Request" setpoint value, the undervoltage timer will begin timing. When the timer expires, the generator undervoltage event is made active (if the voltage has been below the threshold level continuously while timing). If the voltage rises above the "Generator Undervoltage Percentage Threshold" setpoint value, the generator undervoltage event will be made inactive and the timer will be reset. If an undervoltage condition is detected, "GEN UNDERVOLTAGE SHUTDOWN" or "GEN UNDERVOLTAGE " will be displayed on the EMCP 4. This warning is to inform the operator of an undervoltage condition.Note: The severity of the undervoltage condition will determine if a warning or shutdown event occurs.Conditions Which Generate This Code:The code for generator undervoltage is generated when the EMCP 4 determines that a generator undervoltage condition has occurred.Test Step 1. TALK TO THE OPERATOR
Determine the conditions that caused the undervoltage condition. Expected Result:An undervoltage 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 undervoltage condition. The condition has been repaired, and the operator wants to put the generator set back into service.Repair: Reset the generator set. Resume normal operation and verify that the problem has been corrected.STOP
NOT OK - The undervoltage condition was not caused by an occurrence known to the operator. Proceed to Test Step 2Test Step 2. CHECK THE SETPOINTS.
View the Generator Undervoltage, Automatic Voltage Regulator (AVR) Desired Voltage Request and Generator AC Monitor setpoints. Make a note of the setpoints. See 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
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.STOPTest Step 3. VERIFY VOLTAGE CAN BE ADJUSTEDVerify that the generator output voltage can be adjusted from the EMCP 4 Display Screen.Expected Result:The generator output voltage can be adjusted from the EMCP 4 Display Screen.Results:
OK - The generator output voltage can be changed from the EMCP 4 display screen.Repair: Adjust the generator output voltage to meet site requirements. Resume normal operation and verify that the problem has been corrected.STOP
NOT OK - The generator output voltage cannot be adjusted. Proceed to Test Step 4Test Step 4. CHECK CAT DATA LINK BETWEEN THE EMCP 4 AND THE VOLTAGE REGULATORRefer to the Electrical System Schematic for the generator set. Check the data link wiring between the EMCP 4 and the voltage regulator. For additional information on troubleshooting the data link, refer to Troubleshooting , "Data Link Circuit Fault ".Results:
OK - The data link wiring is correct. Proceed to Test Step 5
NOT OK - The wiring is not correctRepair: Repair the data link wiring