PowerFlex 750-Series AC Drives User Manual

1-22 Installation/WiringUsing Input/OutputContactorsInput Contactor Precautions!!ATTENTION: A contactor or other device that routinelydisconnects and reapplies the AC line to the drive to start andstop the motor can cause drive hardware damage. The drive isdesigned to use control input signals that will start and stop themotor. If an input device is used, operation must not exceed onecycle per minute or drive damage will occur.ATTENTION: The drive start/stop/enable control circuitryincludes solid state components. If hazards due to accidentalcontact with moving machinery or unintentional flow of liquid,gas or solids exist, an additional hardwired stop circuit may berequired to remove the AC line to the drive. An auxiliary brakingmethod may be required.Output Contactor Precautions!ATTENTION: To guard against drive damage when usingoutput contactors, the following information must be read andunderstood. One or more output contactors may be installedbetween the drive and motor(s) for the purpose of disconnectingor isolating certain motors/loads. If a contactor is opened whilethe drive is operating, power will be removed from the respectivemotor, but the drive will continue to produce voltage at the outputterminals. In addition, reconnecting a motor to an active drive (byclosing the contactor) could produce excessive current that maycause the drive to fault. If any of these conditions are determinedto be undesirable or unsafe, an auxiliary contact on the outputcontactor should be wired to a drive digital input that isprogrammed as “Enable.” This will cause the drive to execute acoast-to-stop (cease output) whenever an output contactor isopened.Dynamic Brake Resistor Considerations!ATTENTION: The drive does not offer protection forexternally mounted brake resistors. A risk of fire exists ifexternal braking resistors are not protected. External resistorpackages must be self-protected from over temperature or acircuit equivalent to Figure C.1 on page C-2 must be supplied.PowerFlex 750-Series User Manual – Publication 750-UM001C-EN-P – September 2009