LINK-TRACK 4821222 - Caterpillar

Caterpillar Generator SetsReference: Service Magazine; July 12, 1993; Page 10; "Preventive Maintenance To Reduce Risk Of Stator Failure"Reference: SEHS9124-01; Special Instruction; "Cleaning and Drying of Electric Set Generators"It is important that electric set generators are stored properly as problems can develop in the generator windings under certain environmental conditions. Most of these problems can be avoided by recognizing the effects of the environment on winding insulation and following protective measures throughout the storage period. Therefore, when a new generator arrives on site it should be protected from collective contaminants and moisture until installation.
Contaminants and moisture that are allowed to collect in the generator during the storage period may be harmful to the generator windings. Collective contaminants such as dirt, dust, grease, oil films, salt, and chemicals increase the risk of moisture collecting in the windings. Moisture can provide a conductive pathway between the bundles of wire. When this occurs, current will leak from the higher voltage bundle to the lower voltage bundle. The current leak produces heat and causes a breakdown and charring of the winding insulation. If the problem goes undetected, the windings may be severely damaged.
Since collective contaminants and moisture may damage generator windings, the generator set should be protected throughout any storage period.
The generator should be stored inside in a dry storage area where possible or covered with a plastic cover or similar type of protective cloth to guard against collective contaminants. The protective cover should extend to the ground, but remain loose to allow the generator to properly breathe. Also apply some type of rust preventative to unpainted parts if a long storage period is anticipated.
In addition, Caterpillar recommends maintaining the insulated parts and the air surrounding them at a temperature of at least 5 ° C (9 ° F) higher than the room temperature in which the equipment is located. This procedure helps to minimize moisture condensation.
Normal methods of providing the heat required are:
1. Space heaters2. Warm air blower. Do not exceed 206.7 kPa (30 psi). 3. Light bulb (60 Watt minimum) installed inside the generator in proximity to the stator core at the lowest possible location.Before placing the generator in storage, it is necessary that a megger insulation resistance check be performed and the results recorded. Refer to Service Magazine; July 12, 1993; Page 10; "Preventive Maintenance To Reduce Risk Of Stator Failure" for the Recommended Megger Insulation Test Procedure. The temperature and level of humidity should also be recorded. This check will provide a baseline for future reference.
It is important that this baseline be established when the unit is dry.Throughout the storage period, it is recommended that the shaft be rotated ten revolutions every 60 days. This procedure helps to insure that grease continues to cover all bearing surfaces.
Before removing a generator from storage and beginning the startup procedure, visually inspect the generator for any foreign material such as rodents, etc. that may have nested in the generator.
Perform another megger insulation resistance check, and compare this new reading to the