February 19, 2016 - Rockwell Automation announces Allen-Bradley Bulletin 140M-D8V motor-protection circuit breakers, suitable for use at the output of variable frequency drives (VFDs) in multimotor installations.
They provide individual overload protection in multiple motor applications as required by NEC. The Bulletin 140M-D8V circuit breakers can be used at the output of VFD. The output frequency of the VFD must be limited to 400 hertz or less to prevent thermal degradation. Various models of the Bulletin 140M-D8V motor-protection circuit breakers provide disconnection for motor branch circuits, branch-circuit and short-circuit protection (including magnetic protection), overload/thermal protection and manual switching. The circuit breakers are current limiting and have a fixed magnetic trip.
Interrupting ratings at 400 volts and 480 volts are available up to 65 kiloamps. The VFD output pulse-width modulation frequency must be limited to 4 kilohertz or less. The circuit breakers provide motor overload protection at trip class 10.
