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 TM 5-685/NAVFAC MO-912
Table 5-2. Switchgear equipment
(2) Troubleshooting. Use recognized industrial
troubleshooting-Continued
practices as the general guide for servicing. Refer to
manufacturer's literature for specific information
Note
on individual voltage regulators. Troubleshooting
Refer to manufacturer's li terature for specific information on
procedures include the following:
individual equipment.
(a) Check voltage for compliance with manu-
facturer's specifications.
(b) Check fo r 1 oose or insecure electrical con-
RELAYS FAILING TO TRIP BREAKERS
nections.
Adjust contacts. verify proper wipe
Contacts improperly adjusted
(c) Check for correct setting, refer to manu-
facturer's literature.
Check to verify that voltage is ap-
Open or short circuit in relay con-
(d) Check for unregulated voltage. Refer to
nections
plied and that current is passing
through relay in question
manufacturer's literature.
(e) Check the enclosure. Should be weather
Improper application of target and
Verify proper tripping action of
holding coil
target and holding coi IS
tight.
(f) Check motor for proper operation and
Faulty or improperly adjusted tim-
If timing device is of bellows or
loose connections. Clean and lubricate as required.
oil-film type, clean and adjust. if of
ing devices
induction-disk type, check for me-
Refer to manufacturer's literature for details.
chanical interference. Refer to
(g) Voltage regulators and associated equip-
manufacturer's literature
ment are normally mounted within switchgear
NOISES DUE TO VIBRATING PARTS
equipment and are interconnected with different
Loose bolts or nuts permitting ex-
Tighten to proper torque value
components. The proper operation and trouble-
cessive vibration
shooting of voltage regulator equipment can depend
Tighten loose nuts or core clamps
Loose laminations in cores of
on these different components. Perform the proce-
transformers, reactors, etc.
to proper torque value
dures in the following table:
CONNECTIONS OVERHEATING
Table 5-2. Switchgear equipment troubleshooting.
Increase of current due to overload
Increase the carrying capacity (in-
crease the number or size of con-
conditions
Note
ductors) Remove excess current
from circuit
Refer to manufacturer's literature for specific information on
individual equipment.
Tighten ail bolts and nuts to proper
Connecting bolts and nuts not tight
torque value
Remedy
Cause
FAILURE IN FUNCTION OF ALL INSTRUMENTS AND DEVICES
WATTHOUR METER INACCURATE
HAVING POTENTIAL WINDINGS
Install new meter, return faulty
Meter may be dirty or damaged
Loose nuts, binding screws or bro- Tighten all loose connections to
meter to repair depot for repair and
ken wire at terminals
proper torque value or repair bro-
ken wire circuits
Inspect and repair as necessary
Faulty wiring or connections
Blown fuse in potential transformer Renew blown fuses
circuit
WATTHOUR METER FAILS TO REGISTER
Blown potential transformer fuse,
Renew blown fuses Check wiring
Repair open circuit and check en-
Open circuit in potential trans-
and repair as required
broken wires or other fault in con-
former primary or secondary cir-
tire circuit for continuity and good
nections
cuits
condition
Remove wedge or block Verify that
Wedge or block accidently left at
BREAKER FAILS TO TRIP
meter is in good operating condi-
time of test or inspection
Lubricate breaker mechanism; refer
Mechanism binding or sticking
tion
to manufacturer's instructions
caused by lack of lubrication
DAMAGED CONTROL, INSTRUMENT TRANSFER SWITCH,
Adjust all mechanical devices,
Mechanism out of adjustment
OR TEST BLOCKS
(toggles, stops, buffers, opening
Dress or clean burned contacts or
Burned or pitted contacts
springs, etc.) according to manu-
replace with new contacts if neces-
facturer's instructions
sary
Examine surface of latch, replace
Failure of latching device
RELAYS FAILING TO TRIP BREAKERS
latch if worn or corroded. Check
Adjust setting to correspond with
Improper setting
latch wipe, adjust according to
circuit conditions. Refer to manu-
manufacturer's instructions
facturer's instructions
Replace damaged coil
Damage trip coil
Clean contact with knife or tile Do
Dirty, corroded or tarnished con-
not use emery cloth or sand-paper
tacts
5-16
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