Table 3-1.--Common Bolt Size Torque Values
Rheostats and Resistors
Be certain that ventilation of rheostats and
resistors is not obstructed. Replace broken or burned
out resistors. Temporary repairs of rheostats can be
made by bridging burned out sections when
replacements are not available. Apply a light coat of
petrolatum to the faceplate contacts of rheostats to
reduce friction and wear. Make sure that no petrolatum
is left in the spaces between the contact buttons as this
may cause burning and arcing. Check all electrical
connections for tightness, and wiring for frayed or
broken leads. Service commutators and brushes for
potentiometer-type rheostats according to instructions
for the dc machines.
The pointer of each switchboard instrument
should read zero (except synchroscopes) when the
instrument is disconnected from the circuit. The
pointer may be brought to zero by external
bus bars should be retaped as necessary according to
NSTM, chapter 320, "Electric Power Distribution
Systems," Check the condition of control wiring and
replace if necessary.
This should not be done unless proper
Bus bars and insulating materials can be cleaned
authorization is given.
with dry wiping cloths and a vacuum cleaner. Make
sure the switchboard or distribution panel is
completely de-energized and tagged out and remains
The pointer should not stick at any point along the scale.
Check instruments for accuracy whenever they have
so until the work is completed. Cleaning energized
been subjected to severe shock. Repairs to switchboard
parts should be avoided because of the danger to
instruments should be made only by the manufacturers,
personnel and equipment. Always observe electrical
shore repair activities, or tenders. For detailed
safety precautions when cleaning or working around
instructions on instruments, refer to NSTM, chapter 491,
"Electrical Measuring and Test Instruments."
Soap and water should not be used on the front
panels of live front switchboards or on other panels of
insulating material. Use a dry cloth.
Make sure that fuses are the right size and that they
The front panels of dead front switchboards may
make firm contact with fuse clips. Ensure that lock-in
be cleaned without de-energizing the switchboard,
devices (if provided) are properly fitted and that all
fuse wiring connections are tight.
These panels can usually be cleaned by wiping with a
dry cloth. However, a damp, soapy cloth may be used
to remove grease and fingerprints. Then, wipe the
surface with a cloth dampened in clear water to
Control circuits should be checked to ensure
remove all soap, and dry with a clean, dry cloth. The
cloths used in cleaning must be wrung out thoroughly
indication lamp operation. Because of the many types
so that no water is left to squeeze out and run down
of control circuits installed in naval ships, it is
impractical to list any definite operating test
the panel. Clean a small area at a time and wipe dry.