Table 7-2.—Controller Troubleshooting Tips

Table 7-2.—Controller Troubleshooting Tips—Continued b. Interrupting excessively high current Check for grounds, shorts, or excessive motor currents c. Excessive jogging Install larger device rated for jogging service d. Weak tip pressure Replace contacts and springs; check carrier for damage e. Dirt on surfaces Clean contacts; reduce exposure f. Short circuits or ground fault Remove fault; be sure fuse/breaker size is correct g. Loose connection Clean then tighten h. Sustained overload Corrosion Check for excessive motor current or install larger controller Excess moisture; salt air; acid fumes Excess wear or friction Failure to break arc Failure to hold load Abrasive dust; high inertia load; excess temperature Too much current; too much voltage (dc); misapplication; too much inductance Worn parts; out of adjustment; misapplication; failure to use recommended substitute parts Failure to make contact Failure to open or close Mechanical damage; dirt; corrosive; wear allowance gone Low voltage; coil open; mechanical binding; mechanical overload; no voltage; wrong coil: shorted turns; excessive magnet gap: mechanical binding; gummy substance on magnet faces: air gap in magnet destroyed; contact tip welded; voltage not removed; corrosion; scale; dirt; operating above rated pressure; damaged motor Failure to operate properly Failure to release Failure to reset overload relay Failure to set overload relay Coils connected wrong; wrong coil; mechanical binding Improper adjustment; coil not energized; mechanical binding: low voltage or current; coil open; shorted turns Mechanical binding; worn parts; dirt; broken mechanism; corrosion; worn parts; resetting to soon Improper adjustment; mechanical binding; coil not de- energized; worn parts Failure to time out (on motor operated relays) Mechanical binding; worn parts; motor damaged; no voltage to motor; dirt Failure to trip (during overload conditions) Heater incorrectly sized; mechanical binding; relay previously damaged by short circuit current; dirt; corrosion; motor and relay in different ambient temperatures Fast trip (on overload relays) Flashover High temperature; wrong heaters Jogging; short circuits; handling too large motor; moisture; acid fumes; gases; dirt Heating Overcurrent; loose connection; spring clips loose or annealed; oxidation: corrosion 7-26