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Table 7-2.—Controller Troubleshooting Tips—Continued | Up
Construction Electrician Intermediate - Electricity handbook for electricians | Next
Chapter 8 Alarm Systems |
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
Corrosion; mechanical damage; excessive pressure; worn
hydraulic controllers)
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
Overheating
Pitted, worn, or broken arc-chutes
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)
Incorrect heat rating; running on starter resistor;
overload; overvoltage; intermittent-rating device
operating too long
Abnormal interrupting duty; excessive vibration or
shock; moisture; improper assembly; rough handling
Extra heating from outside; copper oxide on ferrules and
clips; high ambient temperature
Overcurrent; moisture; corrosive atmospheres
Premature blowing of protective fuses
Resistor failure (on static accessories)
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)
Trips too low (on overload relay)
Various mechanical failures
Wrong size fuse for application
Wrong heater; relay in high ambient temperature (motor)
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
7-27
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