Rockwell Automation Publication 750-TG100B-EN-P - June 2019 43
Preventative Maintenance Chapter 2
instructions. Note: Allen-Bradley® magnetic starters, contactors, and relays are
designed to operate without lubrication. Do not lubricate these Allen-Bradley
devices because oil or grease on the pole faces (mated surfaces) of the operating
magnet can cause the device to stick in the “ON” mode. Some parts of other
devices are factory lubricated – if lubrication during use or maintenance of these
devices is needed, it is specified in their individual instructions. If in doubt,
consult your nearest Rockwell Automation sales office for information.
Contacts - Check contacts for excessive wear and dirt accumulation. Wipe
contacts with a soft cloth, if necessary, to remove dirt. Discoloration and slight
pitting does not harm contacts. Do not file contacts - this action shortens the life
of the contact. Do not use contact spray cleaners because residue on magnet pole
faces or in operating mechanisms can cause sticking, and on contacts can interfere
with electrical continuity. Replace contacts only after the silver has become badly
worn. Always replace contacts in complete sets to avoid misalignment and
uneven contact pressure.
Ter m in a ls - Loose connections in power circuits can cause overheating that can
lead to equipment malfunction or failure. Loose connections in control circuits
can cause control malfunctions. Loose bond or ground connections can increase
hazards of electrical shock and contribute to electromagnetic interference (EMI).
Check the tightness of all terminals and bus bar connections and torque any loose
connections properly. Infrared technology can be used to check for hot (high
resistance/loose) connections during periodic maintenance. Replace any parts or
wiring that is damaged by overheating, and any broken wires or bond straps.
Coils - If a coil is overheated (contains cracked, melted, or burned insulation), it
must be replaced. In that event, check for and correct overvoltage or
undervoltage conditions, which can cause coil failure. Be sure to clean any
residues of melted coil insulation from other parts of the device or replace such
parts.
Pilot Lights - Replace any burned out lamps or damaged lenses. Photoelectric
Switches-The lenses of photoelectric switches require periodic cleaning with a
soft dry cloth. Reflective devices that are used with photoelectric switches also
require periodic cleaning. Do not use solvents or detergents on the lenses or
reflectors. Replace any damaged lenses and reflectors.
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