Motor Start/Stop Precautions 2-121
Motor Start/Stop
Precautions
Input Contactor Precautions
Output Contactor Precaution
Bypass Contactors
!
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.
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