TM 5-684/NAVFAC MO-200/AFJMAN 32-1082
Table 11-2. Troubleshooting chart for general control equipment (continued)
Course of action
Install silver-faced tips. If copper tips, file with
1. Copper oxide on contact tips or tips in poor
Overheating of contact tips
a fine file or replace tips. CAUTION: Excess
filing wears out the tips. Never file silver-faced
2. Carrying load continuously for a long time. Install silver-faced tips or clean tips. Check
Install silver-faced tips.
3. High inductive loads
Reduce current or install a larger device.
4. Sustained overload.
Clean, adjust, check springs.
5. Low tip pressure.
Clean and tighten. Check voltage drop across
6. Loose connection.
Eliminate short circuits or use smaller fuses in
1. Feeder fuses too large
Short circuit currents on contacts
Install special tips designed to withstand arc-
1. Interrupting high currents. Tip life varies
Short tip life.
ing better than copper. (There are cases where
approximately inversely as the square of the
these cannot be used because of their high re-
sistance and lower rating.) For jogging service,
install larger device designed for jogging ser-
Do not file silver tips. The rough spots will not
2. Excessive filing or dressing..
Change to air break device if oil is not essen-
3. Oil immersed device is a misapplication.
(NOTE: Oil immersed tips burn away from 20 tial.
to 40 times as fast as similar tips breaking
the same current in air.).
Reduce rebound, or report trouble to manu-
4. Mechanical rebound on dropout, causing
tips to touch.
1. Defective part.
Weak tip pressure
Replace and adjust.
2. Wear allowance gone..
Adjust gap and wipe.
3. Poor tip adjustment..
Correct voltage condition (possible line regula-
4. Low voltage that prevents magnet sealing
Reduce currents. Substitute special nonweld
1. Abnormal inrush of currents of more or
Welding or freezing
tips. Install larger device. Install copper tips.
less than 10 times continuous rating. This
CAUTION: The possibility of overheating cop-
will vary, depending on the type of device.
per tips should be considered.
Install copper tips if otherwise suitable
2. Rapid jogging.
1. Loose connection.
Relocate coils or use special resistant coils.
2. Moisture, corrosive atmosphere.
Dry out coils.
Do not handle coils by the leads.
1. Mechanical damage..
Open circuit not roasted.
2. Excess vibration or shock; coil movement
causing insulation failure or broken wire.
Check application and circuit.
1. Overvoltage or high ambient.
2. Wrong coil, short time rated coil energized
Replace coil and correct conditions if practical
3. Shorted turns, caused by mechanical dam-
to do so.
age, corrosion, or conducting dust..
4. Too frequent operation (very rapid jogging
of ac coils).
Check circuit interlock.
5. Under-voltage, failure of magnet to seal in.
Series coils overheated (Includes
Install larger coil, or reduce current.
Relocate, or reduce temperature.
2. High ambient.
If connection is hot, clean before tightening.
3. Loose connection, corrosion, oxidation on
See manufacturer's instructions.
1. Improper installation.
Flexible shunt failure
2. Too many operations
3. Worn out mechanically.
Replace shunt and correct condition.
4. Corrosive atmosphere or moisture.
Check application and system voltage.
5. Burned by arcing; oxidized connection