44 Rockwell Automation Publication 750-TG100B-EN-P - June 2019
Chapter 2 Preventative Maintenance
Solid-state Devices
High-Voltage Testing - Do not perform high-voltage insulation resistance (IR)
and dielectric withstanding voltage (DWV) tests to check solid-state control
equipment. When measuring IR or DWV of electrical equipment such as
transformers or motors, a solid-state device that is used for control or monitoring
must be disconnected before performing the test. Even though no damage is
readily apparent after an IR or DWV test, the solid-state devices are degraded and
repeated application of high voltage can lead to failure.
Locking and Interlocking Devices - Check these devices for proper working
condition and capability of performing their intended functions. Make any
necessary replacements only with Allen-Bradley renewal parts or kits. Adjust or
repair only in accordance with Allen-Bradley instructions.
Maintenance After a Fault Condition - An open short circuit protective device
(such as a fuse or circuit breaker) in a properly coordinated motor branch circuit
is an indication of a fault condition in excess of operating overload. Such
conditions can damage control equipment. Before power is restored, the fault
condition must be corrected and any necessary repairs or replacements must be
made to restore the control equipment to good working order. See NEMA
Standards Publication No. ICS-2, Part ICS2-302 for procedures. For
replacements, use only parts and devices that Rockwell Automation recommends
maintaining the integrity of the equipment. Make sure that the parts are properly
matched to the model, series, and revision level of the equipment.
Final Check Out - After maintenance or repair of industrial controls, always test
the control system for proper function under controlled conditions to avoid a
control malfunction hazard. For additional information, see NEMA ICS 1.3,
PREVENTIVE MAINTENANCE OF INDUSTRIAL CONTROL AND
SYSTEMS EQUIPMENT, published by the National Electrical Manufacturers
Association, and NFPA 70B, ELECTRICAL EQUIPMENT
MAINTENANCE, published by the National Fire Protection Association.
ATTENTION: Use of other than factory-recommended test equipment for solid-
state controls can result in damage to the control or test equipment or
unintended actuation of the controlled equipment. See paragraph titled HIGH
VOLTAGE TESTING.
Solid-state devices require little more than a periodic visual inspection. Discolored,
charred, or burned components can indicate the need to replace the component or
circuit board. Make necessary replacements only at the circuit board or plug-in
component level. Inspect printed circuit boards to determine whether they are
properly seated in the edge board connectors. Board locking tabs must also be in
place. Solid-state devices must also be protected from contamination, and
temperature control provisions must be maintained - refer to paragraphs titled
CONTAMINATION and COOLING DEVICES. Do not use solvents on printed circuit
boards.
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