Standby Electric Sets
Most standby units are automatic. They start, pick up
the load, run and stop without an operator in attendance.
Standby units can not change the governor control
setting automatically. The governor control must be
preset
for the proper operation of that unit. Whenever the set is
exercised or operated manually, be sure the governor
speed setting is correct for automatic operation. Check
all switches to see they are properly set: Start Selector
Switch in AUTOMATIC position and any Emergency
Stop Switches in RUN position.
Generator Storage
Storage Procedure
When a generator is in storage for any length of time,
moisture condenses in the windings. Minimize the
condensation by use of a dry storage space and space
heaters.
If a brush-type generator (SRCR) is to be in storage for a
year or more, lift the brushes off the slip ring to prevent
damage to the slip ring by chemical action.
After Storage
NOTE: Test the main stator windings with a megohm
meter in the following situations:
1. Before initial startup of generator set.
2. Every 3 months* if generator is operating in a humid
environment.
3. If generator has not been run under load for 3
months* or more.
The megohmmeter test is described in Service Manuals
SENR2180 or SENR7968. A reading of 1 meghom or
less indicates that the winding has absorbed too much
moisture.
To remove moisture caused by high humidity, use one of
the following methods to make the generator dry:
1. Energize space heaters in generator if so equipped.
2. Put the generator in an oven at a temperature of not
more than 85C (185°F) for four hours.
CAUTION
If an oven is used for drying, use a
forced air type rather than a radiant
type. Radiant ovens can cause
localized overheating.
3. Space heaters of the same type used in marine
applications, can be installed on generators. (See the
Parts Book.) These heaters heat the windings to remove
moisture and should be connected at all times in high
humidity conditions whenever the generator is not
running.
4. Use a canvas enclosure around the generator and
heating lamps to increase the temperature. Make an
opening in the top for release of moisture.
5. Send a low voltage current through the windings to
increase the temperature of the windings. Do not
exceed 85°C (185F).
If the megohmmeter test reads under 1 megohm after
the drying or if it goes below 1 megohm shortly after
drying, contact your Caterpillar dealer. The insulation
has deteriorated and should be reconditioned.
*This is a guideline only. It may be necessary to megger
more frequently if environment is extremely humid, salty
or if the last megger test was close to 1 megohm.
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