SEAL AS 4876304 - Caterpillar

below.Undervoltage - Generator voltage is less than specified for too long a time.Overexcitation - The measured field current is too high for too long a time.When a fault occurs, the digital voltage regulator automatically flashes the corresponding fault code on the display and takes the necessary preventive action. For shutdown faults, the digital voltage regulator disables the output to the exciter. While a fault is present, the fault code information shown on the display will be flashing. If a shutdown fault occurs, the shutdown fault MUST BE RESET in order for the digital voltage regulator to begin operation again. The method to reset a shutdown fault depends upon the classification of the fault. When a fault code is reset, the display will stop flashing. The digital voltage regulator will begin generator output regulation again, according to generator/engine speed and the mode selected. For more information, see System Operation, "Fault Classifications".Fault code 601 - Internal Memory Failure. This fault is an alarm fault. The EEPROM failed during a read action.Note: Reset the fault. Clear the fault. If the alarm reoccurs, check all parameter values between 1 and 38 by using the function keys on the face of the digital voltage regulator or remote communications. This refreshes the programmed values and should eliminate the alarm condition. If the alarm persists, verify that proper grounding, shielding, and electromagnetic noise reduction practices have been followed in the installation before replacing the digital voltage regulator.Fault code 602 - Internal Watchdog Failure. This fault is an alarm fault. A microprocessor watchdog is intended to detect when the microprocessor gets "lost" and to restart the microprocessor again. The watchdog alarm indicates that the digital voltage regulator just came out of a watchdog-induced microprocessor restart.Note: A possible cause is electro magnetic interference (EMI). It may be necessary to provide shielded cable, grounded on one end, for all potentiometers. Another possible cause is the battery voltage being too low (less than 18 VDC). See watchdog alarm, fault code 602. Refer to Testing And Adjusting, "Watchdog Alarm - Troubleshoot".Fault code 603 - Rotating Diode. Check the diodes as per the generator service manual. This fault is a resettable shutdown fault. The digital voltage regulator detects that the variation (ripple) of exciter field current exceeds the diode monitor trip point (parameter :19) for a period of five seconds. A large variation in the exciter field current will occur if a rotating diode fails, shorted or open. This may also occur with good diodes under varying loads if the diode monitor trip point is set too low (too sensitive).Note: For troubleshooting purposes it is useful to know that this alarm fault is often followed by an overexcitation shutdown fault. If an overexcitation shutdown fault (fault code 703) is found in parameter :92, check parameter :93 (or the alarm parameter :95 if it exists) for the presence of the rotating diode monitor alarm code.Fault code 604 - Reverse VAR (only available on 155-xxxx and later regulators). This fault is an alarm