Motor control centers have units or buckets with an extendable/retractable power connection (stab) assembly and one or more operating lever interlocks that include a unit latch to latch to a cabinet and a power connection position interlock that blocks the handle of the units or buckets based on position of the power connection assembly, optionally also including a shutter cam that slides a shutter right and left.

A closed door operation racking device is provided for racking a circuit breaker to and from a power bus from outside of a housing of a motor control center unit. The racking device includes a racking operator assembly and a push-button interlock assembly. The racking operator is configured to rack-in the electrical device and connect the stabs to a power bus in a connected position and to rack-out the electrical device and disconnect the stabs from the power bus in a disconnected position. The push-button interlock assembly prevents the operation of the racking operator under certain conditions, and includes a spring-loaded locker assembly and a spring-loaded push-button operator assembly. A push-button operator of the push-button operator assembly is depressed to disengage the locker assembly from the racking operator to allow operation of the racking operator.

A motor control unit (MCU) and methods of operating and assembling the same are provided. The MCU includes a housing enclosing a retractable stab assembly (RSA) having stabs attached thereto. The MCU further includes a bracket assembly having a mount for securing the bracket assembly to the RSA, guiderails for slideably engaging the RSA to facilitate the extending and retracting motion, and a lead screw accessible via an opening in the front of the housing. Rotating the lead screw causes the RSA to extend and retract which engages and disengages the stabs. The MCU also includes a motor assembly having a drive motor coupled to a drive shaft. The motor rotates the shaft in response to control signals from a remote-device. The motor assembly attaches to the housing such that the rotation of the shaft in response to the signals rotates the lead screw to engage and disengage the stabs.

A motor control unit (MCU) and methods of operating and assembling the same are provided. The MCU includes a housing enclosing a retractable stab assembly (RSA) having stabs attached thereto. The MCU further includes a bracket assembly having a mount for securing the bracket assembly to the RSA, guiderails for slideably engaging the RSA to facilitate the extending and retracting motion, and a lead screw accessible via an opening in the front of the housing. Rotating the lead screw causes the RSA to extend and retract which engages and disengages the stabs. The MCU also includes a motor assembly having a drive motor coupled to a drive shaft. The motor rotates the shaft in response to control signals from a remote-device. The motor assembly attaches to the housing such that the rotation of the shaft in response to the signals rotates the lead screw to engage and disengage the stabs.

Disclosed in the present invention is an electric switching apparatus, comprising a drawer apparatus, an electric connection apparatus, a driving mechanism, and a locking mechanism. A busbar of the breaker body at the separate position is separated from the electric connection apparatus, and the breaker body cannot be switched on. The busbar of the breaker body at the trial position is separated from the electric connection apparatus, and the breaker body can be switched on. The busbar of the breaker body at the connected but not clamped position is in touch with the electric connection apparatus, the electric connection apparatus does not clamp the busbar, and the breaker body cannot be switched on. The busbar of the breaker body at the connected and clamped position is in touch with the electric connection apparatus, the electric connection apparatus clamps the busbar, and the breaker body can be switched on.

Disclosed in the present invention is an electric switching apparatus, comprising a drawer apparatus, an electric connection apparatus, a driving mechanism, and a locking mechanism. A busbar of the breaker body at the separate position is separated from the electric connection apparatus, and the breaker body cannot be switched on. The busbar of the breaker body at the trial position is separated from the electric connection apparatus, and the breaker body can be switched on. The busbar of the breaker body at the connected but not clamped position is in touch with the electric connection apparatus, the electric connection apparatus does not clamp the busbar, and the breaker body cannot be switched on. The busbar of the breaker body at the connected and clamped position is in touch with the electric connection apparatus, the electric connection apparatus clamps the busbar, and the breaker body can be switched on.

A panel for accommodating a draw-out device, such as a vacuum circuit breaker or metering device, includes: a housing with an access opening for accommodating a draw-out device and with primary plugs and secondary plugs connectable to the draw-out device; a traveling system arranged in the housing and for positioning the draw-out device within the housing in a connected position, a service position, and a disconnected position; a door arranged on the housing and movable between a closed position to close the access opening and an open position for provide access to the housing; a primary blocking element for blocking movement of the traveling system from the disconnected position to the service position with the door in the open position or between the open position and the closed position; and a secondary blocking element for blocking the door to move into the closed position with the draw-out device being disconnected.

A panel for accommodating a draw-out device, such as a vacuum circuit breaker or metering device, includes: a housing with an access opening for accommodating a draw-out device and with primary plugs and secondary plugs connectable to the draw-out device; a traveling system arranged in the housing and for positioning the draw-out device within the housing in a connected position, a service position, and a disconnected position; a door arranged on the housing and movable between a closed position to close the access opening and an open position for provide access to the housing; a primary blocking element for blocking movement of the traveling system from the disconnected position to the service position with the door in the open position or between the open position and the closed position; and a secondary blocking element for blocking the door to move into the closed position with the draw-out device being disconnected.

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.

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.