Rockwell Automation SP600 AC Drive User Manual Version 1.0 - Manual (Page 58)

4-4 SP600 AC Drive User Manual
4.1.2 Using Input/Output Contactors
Input Contactor Precautions
Output Contactor Precaution
!
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.
Disconnecting a motor under load can cause
damage to the contactor as well as the drive because
the DV/DT (change in voltage/Change in time) is
severe causing a rapid increase in current at the
contacts and the resultant current draw from the
drive. If at all possible, a control scheme should
attempt to send a stop to the drive to minimize any
energy being sent to the motor before opening the
contactors. 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, helping to
prevent the drive from operating without the
contactors’ prior closure.