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6. After the generator is dry and the
insulation resistance is brought up to
specification remove the short circuit from
the line lead disconnect the dc source and
reconnect the F and F2 leads at the
regulator. Be sure all connections are tight
and correct before attempting to run the
generator.
CLEANING METHODS
When electrical components get dirty, the
insulation must be cleaned. There are a
number of acceptable methods for cleaning
the generator, each of which will necessitate
disassembly of the unit. The kind of dirt, and
when the unit must be returned to service
will determine the method of cleaning.
Drying after cleaning is necessary.
Whenever the generator is disassembled, the
windings should be given a thorough
inspection and the insulation cleaned, if
necessary. The inspection should include the
connection of the windings, insulation, and
varnish coverage. Check the winding ties
and coil supports. Look for any signs of coil
movement or looseness and repair as
required.
An electric motor repair shop in your area
can normally assist with the proper cleaning
of the generator windings. They may also be
experienced in special problems (such as
seacoast, marine, oilrig, mining, etc.) that
may be peculiar to a certain area.
Solvents
A solvent is usually required to remove
accumulated soil containing oil or grease.
Only petroleum distillates should be used for
cleaning electrical components. Petroleum
solvents of the safety type with a flash point
greater than 100° F (38° C) are
recommended.
CAUTION: A SOLVENT THAT DOES NOT
ATTACK EPOXY OR POLYESTER
BASED MATERIALS SHOULD BE USED.
Apply the solvent with a soft brush or rag.
Be careful not to damage the magnet wire or
insulation on the windings.
Dry components thoroughly with moisture-
free, low pressure compressed air.
Cloth and Compressed Air
Cleaning with a dry cloth may be
satisfactory when components are small, the
surfaces are accessible and only dry dirt is
removed. Blowing dirt out with compressed
air is usually effective particularly when the
dirt has collected in places that cannot be
reached with a cloth. Use clean dry air at 30
PSI (206 KPA).
Brushing and Vacuum Cleaning
Dry dust and dirt may be removed by
brushing with bristle brushes followed by
vacuum cleaning. Do not use wire brushes.
Vacuum cleaning is an effective and
desirable method of removing dry and loose
dirt.
Shell Blasting
Air blasting with ground nut shells may be
satisfactory for removal of hard dirt deposits
from insulation. Use mild abrasives such as
12-20 mesh ground walnut shells.
Steam Cleaning
If the generator is completely disassembled,
including bearings and electronic
components, steam cleaning of the major
parts and windings is very effective.
However, the machine must be thoroughly
dried in an oven to remove all moisture
before the generator can be put back into
service.
