Motor Start/Stop Precautions - Allen-Bradley PowerFlex 70 Reference Manual

Motor Start/Stop Precautions

Motor Start/Stop
Precautions
120
Input Contactor Precautions
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.
Output Contactor Precaution
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.
Bypass Contactors
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.
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013