The present disclosure provides a plug interlock device for a circuit breaker, comprising: a lever-type withdrawable interlock assembly provided at a transfer car so that inputting and withdrawal of a breaker main body can be locked; a plug connector assembly, which rises/lowers in response to insertion or separation of a control line plug into or from a connector provided at the upper part of the breaker main body; a shaft, which rotates in different directions according to the elevation of the plug connector assembly by connecting one side thereof to the lower end of the plug connector assembly; and a blocking plate connected to the other side of the shaft so as to lock or unlock the operation of the lever-type withdrawable interlock assembly while horizontally moving according to the rotation of the shaft.

The present disclosure provides a plug interlock device for a circuit breaker, comprising: a lever-type withdrawable interlock assembly provided at a transfer car so that inputting and withdrawal of a breaker main body can be locked; a plug connector assembly, which rises/lowers in response to insertion or separation of a control line plug into or from a connector provided at the upper part of the breaker main body; a shaft, which rotates in different directions according to the elevation of the plug connector assembly by connecting one side thereof to the lower end of the plug connector assembly; and a blocking plate connected to the other side of the shaft so as to lock or unlock the operation of the lever-type withdrawable interlock assembly while horizontally moving according to the rotation of the shaft.

Cradle-assist assemblies attached to the breaker cradle housing and/or base or residing at least partially in the breaker cradle housing and/or base include at least one actuator configured to laterally translate the at least one right and the at least one left lock members from the extended lock position to the retracted unlocked position in response to input from a user. The at least one actuator and/or transverse member(s) can be held in a defined position so that the lock members of the cradle can be locked in the respective retracted or extended positions until the cradle assist (internal) lock is manually or automatically released.

Cradle-assist assemblies attached to the breaker cradle housing and/or base or residing at least partially in the breaker cradle housing and/or base include at least one actuator configured to laterally translate the at least one right and the at least one left lock members from the extended lock position to the retracted unlocked position in response to input from a user. The at least one actuator and/or transverse member(s) can be held in a defined position so that the lock members of the cradle can be locked in the respective retracted or extended positions until the cradle assist (internal) lock is manually or automatically released.

A system and method are provided for coordinating the installation and removal a motor control center subunit with the power connection and interruption thereof. A system of interlocks and indicators causes an operator to install a motor control center subunit into a motor control center, and connect supply and control power thereto, in a particular order. Embodiments of the invention may prevent actuation of line contacts of the bucket, and shield the line contacts, until the bucket is fully installed in the motor control center. Other embodiments also prevent circuit breaker closure until the line contacts are engaged with a bus of the motor control center.

A system and method are provided for coordinating the installation and removal a motor control center subunit with the power connection and interruption thereof. A system of interlocks and indicators causes an operator to install a motor control center subunit into a motor control center, and connect supply and control power thereto, in a particular order. Embodiments of the invention may prevent actuation of line contacts of the bucket, and shield the line contacts, until the bucket is fully installed in the motor control center. Other embodiments also prevent circuit breaker closure until the line contacts are engaged with a bus of the motor control center.

A method for monitoring switchgear, provided with a switching mechanism, including: monitoring an electric power supply signal to an electromagnetic actuator of the switching mechanism in order to detect the start of the supply of electric power to the actuator, monitoring an impact intensity measurement in the switchgear in order to detect the setting in motion of the switching mechanism, monitoring a parameter representative of the open or closed state of the switchgear in order to detect a change in state of the parameter, representative of an end of an opening or closing sequence of the switchgear.

The method further includes: calculating a time T.sub.ACT that has elapsed between the detection of the start of the supply of electric power to the actuator and the detection of the setting in motion of the switching mechanism of the switchgear, calculating a time T.sub.M that has elapsed between the setting in motion of the switching mechanism and the sequence end.

A method for monitoring switchgear, provided with a switching mechanism, including: monitoring an electric power supply signal to an electromagnetic actuator of the switching mechanism in order to detect the start of the supply of electric power to the actuator, monitoring an impact intensity measurement in the switchgear in order to detect the setting in motion of the switching mechanism, monitoring a parameter representative of the open or closed state of the switchgear in order to detect a change in state of the parameter, representative of an end of an opening or closing sequence of the switchgear.

The method further includes: calculating a time T.sub.ACT that has elapsed between the detection of the start of the supply of electric power to the actuator and the detection of the setting in motion of the switching mechanism of the switchgear, calculating a time T.sub.M that has elapsed between the setting in motion of the switching mechanism and the sequence end.

A motor control center includes an enclosure comprising an isolation switch, a main contactor device, and a ground switch device. The isolation switch is selectively manually operable between a connected state and a disconnected state. In the connected state the isolation switch is adapted to conduct electrical power from an associated power source to the main contactor device and wherein the isolation switch in the disconnected state interrupts conduction of electrical power from the associated power source to the main contactor device. The main contactor device is selectively operable between a conductive state and a non-conductive state, wherein the main contactor device is adapted to electrically connect the isolation switch to the ground switch device and to an associated electrical load when the main contactor device is in its conductive state and wherein the main contactor device disconnects said isolation switch from the ground switch device and the associated electrical load when the main contactor device is in its non-conductive state. The ground switch device is manually operable from an open, ungrounded state in which the main contactor device is electrically disconnected from a ground path to a closed, grounded state in which the main contactor device is electrically connected to the ground path. The motor control center further includes an interlock device operably connected between the isolation switch and the ground switch device, wherein the interlock device prevents movement of the isolation switch from the disconnected state to the connected state when the ground switch device is in the grounded state.

A motor control center includes an enclosure comprising an isolation switch, a main contactor device, and a ground switch device. The isolation switch is selectively manually operable between a connected state and a disconnected state. In the connected state the isolation switch is adapted to conduct electrical power from an associated power source to the main contactor device and wherein the isolation switch in the disconnected state interrupts conduction of electrical power from the associated power source to the main contactor device. The main contactor device is selectively operable between a conductive state and a non-conductive state, wherein the main contactor device is adapted to electrically connect the isolation switch to the ground switch device and to an associated electrical load when the main contactor device is in its conductive state and wherein the main contactor device disconnects said isolation switch from the ground switch device and the associated electrical load when the main contactor device is in its non-conductive state. The ground switch device is manually operable from an open, ungrounded state in which the main contactor device is electrically disconnected from a ground path to a closed, grounded state in which the main contactor device is electrically connected to the ground path. The motor control center further includes an interlock device operably connected between the isolation switch and the ground switch device, wherein the interlock device prevents movement of the isolation switch from the disconnected state to the connected state when the ground switch device is in the grounded state.