TUBE AS 2138287 - Caterpillar

When water pressure is used for cleaning purposes, the pressure of the water must not exceed 205 kPa (30 psi) otherwise damage to the equipment may occur.
Flush the unit with fresh warm water in order to remove all traces of salt and silt. Washing should continue until tests of the fresh water show the insulation to be free of salt.Note: Complete disassembly of the generator may be necessary, in order to accomplish a proper cleaning.Bake and dry the unit completely with externally applied heat before placing back into service. Refer to the procedure in "Drying" for more information.Note: If the generator is used in or near salty air and high humidity environments, special electric component cleaners and protectors are needed to prevent corrosion.Drying
Drying may be accomplished by external heat, internal heat, a combination of internal heat and external heat, or circulating current.
When using external heat to dry the generator, do not exceed 85° C (185° F) otherwise damage to the equipment may occur.
External heat is the most preferable method. Insulation drying time can vary from a few hours to several days, depending on moisture content and the process used for drying.Note: Drying sometimes does not produce the required results. The use of a qualified rebuild shop for drying and redipping of the generator may be necessary.
Illustration 3 g01697133
Typical curves of the resistance in the insulation that is drying
(3) Curve of the temperature in the windings
(4) Heat turned off.
(5) Drying time in hours
(6) Temperature in degrees Celsius
(7) Curve of insulation resistance during drying process
(8) Insulation resistance in megaohmsNote: When new insulation or damp insulation is being dried, the resistance will probably fall rapidly as the temperature is raised to a value for drying. After reaching a minimum for a given temperature, the resistance will again rise as moisture is driven out of the insulation. The actual values will vary with each situation. Refer to Illustration 3.If the windings or insulation become wet during the resistance measurement: Use a five megaohms resistor for protection, in series with the red positive lead, to limit the voltage across the circuit under test. Use this method until drying is well in progress, and the resistance has reached an acceptable level.During the drying period, check the windings every 4 hours, or every hour, for the method of circulating current with the insulation resistance tests. Refer to "Insulation Resistance Tests" for more information.Drying is complete when the testing demonstrates that PI > = 2. Record these readings in the Generator Test Data Sheet and compare to previous readings. Keep these records for future reference.External Heat
Ovens
The best oven is a forced air drying oven for drying electrical equipment. Radiant ovens sometimes cause localized overheating.
Do not heat the generator too quickly. Try to limit the rise in temperature of the insulation and windings to 11° C (19.8° F) per hour. Failure to do so may cause equipment damage.
Heat the generator to a maximum temperature of 85 °C (185 °F) for a minimum of 4 hours.Alternate Method
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