194 Rockwell Automation Publication 1560F-UM001A-EN-P - June 2019
Chapter 10 Maintenance
Terminals
Loose connections can cause overheating that can lead to equipment malfunction
or failure. Check the tightness of all terminals and bus bar connections and
securely tighten any loose connections. Replace any parts or wiring damaged by
overheating.
Coils
If a coil exhibits evidence of overheating (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.
Solid-State Devices
Solid-state devices require little more than a periodic visual inspection. Printed
circuit boards should be inspected to determine whether all cables are properly
seated in their connectors. Board locking tabs should also be in place. Necessary
replacements should be made only at the PC board or plug-in component level.
Solvents should not be used on printed circuit boards. Where blowers are used,
air filters, if supplied, should be cleaned or changed periodically depending on
the specific environmental conditions encountered. For additional information
see NEMA Standards Publication No. ICS 1.1 - 1987 entitled “Safety Guidelines
for the Application, Installation and Maintenance of Solid-State Control”.
Static-Sensitive Items
While performing maintenance on the MV SMC, special precautions must be
observed in handling or touching certain static-sensitive components in the
cabinet. Most circuit cards and SCRs can be damaged by Electro-Static
Discharge (ESD). If personnel will make contact with an ESD-sensitive
component during maintenance, they must be grounded. Grounding should be
accomplished with a wrist strap which is connected to an approved ground.
ATTENTION: Use of other than factory recommended test equipment for solid-
state controls may result in damage to the control or test equipment, or
unintended actuation of the controlled equipment.
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