Rockwell Automation 21G PowerFlex 750-Series AC Drives - Manual (Page 176)

176 Rockwell Automation Publication 750-IN001N-EN-P - April 2014
PowerFlex 750-Series AC Drives
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.
IMPORTANT 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.