BELT-SERPENTINE 1974567 - Caterpillar

Introduction
When servicing or repairing electric power generation equipment, do the following:a. Make sure the unit is off-line (disconnected from utility and/or other generators power service), and either locked out or tagged "DO NOT OPERATE".b. Make sure the generator engine is stopped.c. Make sure all batteries are disconnected.d. Make sure all capacitors are discharged.When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present. Make sure the testing equipment is designed for and correctly operated for the high voltage and current tests being made. Improper test equipment may fail and present a high voltage shock hazard to its user.
Do not connect the generator to a utility electrical distribution system, unless it is isolated from the system. Electrical feedback into the distribution system can occur and could cause personal injury or death.Open and secure the main distribution system switch or, if the connection is permanent, install a double throw transfer switch to prevent electrical feedback. Some generators are specifically approved by a utility to run in parallel with the distribution system and isolation may not be required. Always check with your utility as to the applicable circumstances.
At all times during operation of a permanent magnet excited generator, the VR3 voltage sensing circuit must be complete. The VR3 voltage sensing lines MUST NOT be open (broken or disconnected). The VR3 fuses MUST be installed. Operating with the voltage sensing circuit open, causes the generator output voltage to go extremely high. Damage to related equipment can occur.
Test Equipment
6V7070 Heavy Duty Digital MultimeterCaterpillar Digital Multimeters measure voltage, resistance or current up to 10 amps. The diode function checks rectifiers. See Special Instruction SEHS7734 for the operation of 6V7070.
4C4693 Regulator TesterThe 4C4693 Regulator Tester is a bench top instrument used to test VR3 regulators. This provides a way to check a regulator without using a generator set.Schematics - Permanent Magnet Excited Generators
Medium Voltage Generator With Two PM Fuses Medium Voltage Generator With Three PM Fuses 4/6 Lead Generator With Two PM Fuses 4/6 Lead Generator With Three PM Fuses 10/12 Lead Generator With Two PM Fuses 10/12 Lead Generator With Three PM Fuses SR4 Generator With Sensing/Isolation Transformer And Two PM Fuses Troubleshooting
Introduction
Check for loose or corroded terminals. Make sure wire connections are correct. Check the accuracy of the voltmeter and frequency meter/tachometer.To reduce troubleshooting time, simplify the system or circuit by eliminating non-essential components such as remote voltage control, manual control, etc. If, at this point, it is determined that the basic system is functioning, the circuits or components can be added back in, one at a time until the problem is located.If elimination of non-essential components does not correct the problem, the troubleshooting procedure will check components in the basic system. If all other basic components (i.e. rotating field assembly, exciter stator, etc.) are operating correctly, then replace the VR3 regulator. As a last step after confirming correct operation under no load conditions, operate the generator under a load.The VR3 regulator is serviced as