BOSS 4V8690 - Caterpillar

Personal injury or death can result from improper troubleshooting and repair procedures.The following troubleshooting and repair procedures should only be performed by qualified personnel familiar with this equipment.
Refer to Safety Section, "Generator Isolating for Maintenance" for information regarding the procedure to safely isolate the generator. Proper maintenance of electrical equipment requires periodic visual examination of the machine and periodic visual examination of the windings. Proper maintenance of electrical equipment also requires appropriate electrical checks and appropriate thermal checks. Insulation material should be examined for cracks. The insulation material should be examined for accumulations of dirt and dust. If there is an insulation resistance value that is below normal, a conductive path may be present. This conductive path may be made of one of the following materials:
Carbon
Salt
Metal dust
Dirt that is saturated with moisture These contaminants will develop a conductive path which may produce shorts. Cleaning is advisable if heavy accumulations of dirt can be seen or if heavy accumulations of dust can be seen. If excess dirt is restricting ventilation, cleaning is also advisable. Restricted ventilation will cause excessive heating.
To avoid the possibility of deterioration to the generator windings, do not clean the generator unless there is visual, electrical, or thermal evidence that dirt is present.
If harmful dirt accumulations are present, a variety of cleaning techniques are available. The cleaning procedure that is used may be determined by one of the items on the following list:
The extent of the cleaning procedure that is being attempted
The type of enclosure of the machine
The voltage rating of the machine
The type of dirt that is being removedField Service Cleaning (Assembled Machines)
Cleaning may be required at the point of installation. At this point, complete disassembly of the machine may not be necessary or feasible. In this case, a vacuum cleaner should be used to pick up the following items: dry dirt, dust and carbon. This will prevent the spreading of these contaminants. A small nonconductive tube may need to be connected to the vacuum cleaner. This will allow the vacuum cleaner to clean non-exposed surfaces. After most of the dust has been removed, a small brush may be attached to the vacuum hose in order to loosen dirt that is more firmly attached to the surface.After the initial cleaning with a vacuum, compressed air may be used to remove the remaining dust and dirt. Compressed air that is used for cleaning should be free of moisture and free of oil. Air pressure should be a maximum of 210 kPa (30 psi) in order to prevent mechanical damage to the insulation. If the above cleaning procedures are not effective, consult a Caterpillar dealer.Field Service Cleaning (Disassembled Machines)
An initial insulation resistance check should be made on the machine in order to confirm electrical integrity. A minimum reading of one megohm would be expected with severely contaminated machines. A zero megohm reading may indicate an insulation breakdown. An insulation breakdown requires more than cleaning. An insulation breakdown requires repair.A high pressure wash is normally an effective way