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 TM 5-683/NAVFAC MO-116/AFJMAN 32-1083
Table 5-2. Motor control trouble-shooting chart-continued.
REMEDY
CAUSE
6. Excessive Corrosion of
Contacts
Check control spring pressure and
Chattering of contacts as a
replace spring if it does not give
result of vibration outside
rated pressure.
If this does not
the control cabinet.
help, move control so vibrations are
decreased.
Replace contact spring.
High contact resistance
because of insufficient
contact spring pressure.
7.
Abnormally Short Coil Life
Check supply voltage and rating of
High Voltage.
controller.
Check travel of armature. Adjust SO
Gap in magnetic circuit
magnetic circuit is completed.
(alternating current only).
Check rating of contact. Get coil
Ambient temperature too high.
of higher ambient rating from
manufacturer, if necessary.
Do not file silver-faced contacts.
Filing or dressing.
Rough spots or discoloration will
not harm contacts.
Install larger device or check for
Interrupting excessively high
grounds, shorts or excessive motor
Use silver-faced
contacts.
Install larger device rated for
Excessive jogging.
jogging or caution operator.
Adjust or replace contact springs.
Weak contact pressure.
Clean contact surface.
Dirt on contact surface.
Remove short circuit fault and check
Short circuits.
for proper fuse or breaker size.
Clean and tighten.
Loose connections.
Install larger device or check for
Sustained overload.
excessive load current.
8. Panel and Apparatus Burned
by Heat From Resistor
Use resister of hiqher rating.
Motor being started frequently
5-21
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