Motor control center units with retractable stabs and interlocks using portal shutters

摘要

Motor control centers have units or buckets with one or more sliding shutters that controllably block access to a stab isolation port based on position of the operator disconnect handle using attached cams that slide the shutter right and left. A front panel of the unit or bucket may also be configured to pivot out about a long axis associated with a bottom long side thereof.

主权项

1. A bucket sub-assembly to control access to a stab isolation portal of a bucket unit, comprising:
first and second spaced apart operator disconnect handles, the first operator disconnect handle attached to a first inwardly extending shaft that holds a first cam, the second operator disconnect handle attached to a second inwardly extending shaft that holds a second cam, wherein the first and second cams are configured to independently rotate, and wherein the first cam rotates in response to a rotation of the first operator disconnect handle and the second cam in response to a rotation of the second operator disconnect handle; and at least one shutter in communication with the first and second cams, wherein the at least one shutter has a shutter portal, and wherein the at least one shutter is configured to cooperate with the first and second cams to laterally slide to a position that misaligns the shutter portal with the stab isolation portal to block access to the stab isolation portal when at least one of the first or the second operator disconnect handles is in an ON position associated with a conduction of electric current through at least one stab of the bucket unit.