Rockwell Automation Publication 750-IN001O-EN-P - October 2014 191
Power Wiring Chapter 4
Input Contactor Precautions
Output Contactor Precaution
Bypass Contactor Precaution
Applying and Removing
Power
ATTENTION: A contactor or other device that routinely disconnects and
reapplies the AC line to the drive to start and stop the motor can cause drive
hardware damage. The drive is designed to use control input signals that will
start and stop the motor. If an input device is used, operation must not exceed
one cycle per minute or drive damage will occur.
ATTENTION: The drive start/stop/enable control circuitry includes solid state
components. If hazards due to accidental contact with moving machinery or
unintentional flow of liquid, gas or solids exist, an additional hardwired stop
circuit may be required to remove the AC line to the drive. An auxiliary braking
method may be required.
ATTENTION: To guard against drive damage when using output contactors, the
following information must be read and understood. One or more output
contactors may be installed between the drive and motor(s) for the purpose of
disconnecting or isolating certain motors/loads. If a contactor is opened while
the drive is operating, power will be removed from the respective motor, but
the drive will continue to produce voltage at the output terminals. In addition,
reconnecting a motor to an active drive (by closing the contactor) could produce
excessive current that may cause the drive to fault. If any of these conditions are
determined to be undesirable or unsafe, an auxiliary contact on the output
contactor should be wired to a drive digital input that is programmed as
“Enable.” This will cause the drive to execute a coast-to-stop (cease output)
whenever an output contactor is opened.
ATTENTION: An incorrectly applied or installed bypass system can result in
component damage or reduction in product life. The most common causes are:
• Wiring AC line to drive output or control terminals.
• Improper bypass or output circuits not approved by Allen-Bradley.
• Output circuits which do not connect directly to the motor.
Contact Allen-Bradley for assistance with application or wiring.
Wait one minute before cycling power disconnect switches. This requirement
applies to both Off-to-On and On-to-Off transitions. Rapid switch cycling may
result in equipment damage.
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