Rockwell Automation Publication 6000-UM002E-EN-P - April 2018 91
Preventative Maintenance and Component Replacement Chapter 5
Medium Voltage Testing
Medium voltage insulation resistance (IR) or dielectric withstanding voltage tests 
should not be used to check solid-state control equipment. When performing IR 
tests on electrical equipment, such as transformers or motors, solid-state devices 
must be bypassed before performing the test. Even though no damage may be 
readily apparent after an IR test, the solid-state devices are degraded and repeated 
application of high voltage can lead to failure.
Maintenance after a Fault Condition
Opening of the short circuit protective device (such as fuses or circuit breakers) 
in a properly coordinated motor branch circuit is an indication of a fault 
condition in excess of operating overload. Such conditions can cause damage to 
medium voltage motor control equipment. Before restoring power, the fault 
condition must be corrected and any necessary repairs or replacements must be 
made to restore the medium voltage motor control equipment to good working 
order. Refer to NEMA Standards Publication No. ICS-2, Part ICS2-302 for 
procedures. Use only replacement parts and devices recommended by Rockwell 
Automation to maintain the integrity of the equipment. Ensure the parts are 
properly matched to the model, series and revision level of the equipment. After 
maintenance or repair of the equipment, always test the control system for proper 
functioning under controlled conditions (that avoid hazards in the event of a 
control malfunction). For additional information, refer to NEMA ICS 1.3, 
PREVENTIVE MAINTENANCE OF INDUSTRIAL CONTROL AND 
SYSTEMS EQUIPMENT, published by the National Electrical Manufacturers 
Association, and NFPA70B, ELECTRICAL EQUIPMENT 
MAINTENANCE, published by the National Fire Protection Association.