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Table 7-2. - Controller Troubleshooting Tips - Continued
| High trip | Mechanical binding; wrong or shorted coil; assembled wrong |
| Insulation failure | Moisture; acid fumes; overheating; accumulation of dirt on surfaces; voltage surges; short circuits; mechanical damage; overvoltage |
| Leaks and mechanical failure (on pneumatic and hydraulic controllers) | Corrosion; mechanical damage; excessive pressure; worn seat; solid matter in seat/strainer |
| Low trip | Wrong coil; assembled wrong |
| Mechanical wear or failure | Abrasive dust and dirt; misapplication; mechanical damage; excessive operating speed |
| Noisy magnet | Broken pole shader; magnet faces not true as result of wear or mounting strains; dirt on magnet faces; low voltage; mechanical overload; improper adjustment (too much pressure or incorrect lever ratio) |
| Overheating | Incorrect heat rating; running on starter resistor; overload; overvoltage; intermittent-rating device operating too long |
| Pitted, worn, or broken arc-chutes | Abnormal interrupting duty; excessive vibration or shock; moisture; improper assembly; rough handling |
| Premature blowing of protective fuses | Extra heating from outside; copper oxide on ferrules and clips; high ambient temperature |
| Resistor failure (on static accessories) | Overcurrent; moisture; corrosive atmospheres |
| Short contact life | Jogging; handling abnormal currents; lack of lubrication where recommended; abrasive dirt |
| Slow trip (of overload relays) | Mechanical binding; dirt; low temperature; wrong heaters |
| Sticking | Dirt; worn parts; improper adjustment; corrosion; mechanical binding |
| Too slow blowing (of fuse) | Wrong size fuse for application |
| Trips too low (on overload relay) | Wrong heater; relay in high ambient temperature (motor) |
| Various mechanical failures | Overvoltage; heavy slamming; chattering; abrasive dust; underload |
| Wear on magnet | Overvoltage; broken pole shader; wrong coil; underload; weak tip pressure; chattering; load out of alignment |
| Wear on segments or shoes (of a rheostat) | Abrasive dust; very heavy duty; no lubrication |