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 TM 5-683/NAVFAC MO-116/AFJMAN 32-1083
)ING
s
J
BREAKER UNIT
COUPLING
Figure 2-8. Typical drawout network protector and enclosure.
check of operating conditions. The conductor sizes
should provide for not less than 135 percent of ca-
pacitor current at rated voltage and WA. As a gen-
eral rule, if the side of the capacitor unit casing is
operating at a temperature above 55 degrees C (131
degrees F a temperature almost too hot for bare-
hand contact), then a more complete investigation
of operating conditions should be made. The case
temperatures should never exceed 65 degrees C
(149 degrees F) under any conditions. Adequate
ventilation is therefore necessary to remove the
heat generated by continuous full-load duty. Re-
move any obstructions at ventilation openings in
capacitor housings to ensure that this ventilation is
Holes
For
Mounting
maintained. A disconnected capacitor retains its
Screws
electrical charge for some time and may even retain
Two On
Each Side
the full-line voltage across its terminals. Therefore
always discharge a capacitor before handling or
making connections. An insulation short circuit
jumper may be used for this purpose; however, it
should only be applied with full knowledge of the
circuit, and with the use of appropriate protective
equipment. Power capacitors are generally provided
with individual fuses to protect the system in case
Figure 29. Network protector removable unit.
of a short circuit within the capacitor. In addition to
a faulty capacitor, a fuse may be blown by an abnor-
importance is often overlooked. The voltage of the
mal voltage surge. Check for blown fuses and re-
system at the capacitor location should be checked
place them with a type recommended by the manu-
at light load periods to determine if an overvoltage
facturer. Do not remove fuses by hand until the
condition exists. Any changes in circuit connections,
capacitor has been completely discharged. Clean the
which may increase voltage levels, warrant a re-
case of a capacitor, the insulating bushings, and any
2-13
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