PAD 2335169 - Caterpillar

All Caterpillar Generators SetsReference: SEBD0660, "Operating Environment-And Its Effects On SR4 Generators"; Special Instruction, SEHS9124, "Cleaning and Drying of Electric Set Generators."There is a potential risk of stator failure for generators stored or operated in contaminated and/or humid environments. Problems can develop in the generator windings when dust, water, salt or grease is present, or anytime the generator windings are below the dewpoint.
Contaminants such as dirt, dust, grease, oil films, salt and water should not be allowed to accumulate on the stator windings. These conditions increase the risk of moisture collecting in the windings. Moisture can provide a conductive pathway between 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.
The following preventive maintenance activities will reduce the risk of stator failure for generators stored or operated in contaminated and/or humid environments.
Safety
When servicing or repairing electric power generation equipment:
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. * Remove all fuses.
* Make sure the generator engine is stopped.* Make sure all batteries are disconnected.* Make sure all capacitors are discharged.* Failure to do so could result in personal injury or death.* Make sure residual voltage in the rotor, stator and the generator is discharged.
Attach a "DO NOT OPERATE" or similar warning tag to start switch or controls before performing any service or repairs.
"DO NOT OPERATE" tags are available from Caterpillar. Order Form SEHS7332.
When power generation equipment must be in operation to make tests and/or adjustments, high voltage and current are present.
* Improper test equipment may fail and present a high voltage shock hazard to its user.* Make sure the testing equipment is designed for and correctly operated for high voltage and current tests being made.
New Equipment
Storage
After a new generator arrives on site it should be protected against moisture until it is installed.
When a generator is in storage, moisture condenses in the windings. To minimize condensation, always put the generator in a dry storage area.
When the generator is placed in storage, it is necessary that a megger insulation resistance check be performed and the results recorded. 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.To guard against collective contaminants, the generator should be covered with a plastic cover or similar type of protective cloth. The protective cover should extend to the ground, but remain loose around the generator in order to allow it to properly breathe.
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 will prevent condensation. Normal methods of providing the heat required are:
1.