Patent Description:
Industrial-sized circuit breakers typically do not have their own racking system, instead the racking system is part of the switchgear cabinet. When a circuit breaker is inserted, it engages the racking system in the cabinet and is then racked into the cabinet. The racking operation may be done either manually or electrically with a motorized racking system that is a part of the cabinet structure. By contrast, industrial-sized circuit breakers are available with a racking system that is an integral part of the breaker, so the motor is no longer stationary. However, connecting a motorized breaker to racking power becomes difficult, because the breaker can move in and out of the cabinet.

Some breakers are available with an umbilical cord power plug connected to the breaker, which must be manually connected to the source of control power and settings before the breaker is racked into the connected position. Making the manual connection within the cabinet is difficult, since the typical cabinet has interlocks that guarantee that the user has inserted the breaker before racking, and prevents taking the breaker out once it is in a connected position. Moreover, the manual process for connection to the source of control power and settings is not desirable since it creates an opportunity for making mistakes. An operator may forget to connect and disconnect the plug, and potentially limit an ability to prevent the operator from disconnecting the plug.

<CIT> discloses a racking system with a circuit breaker comprising a movable terminal and a fixed terminal. The movable terminal moves automatically with a horizontal movement of the circuit breaker in a breaking position, a testing position and an operating position. The disclosed racking system comprises a racking motor configured to move the circuit breaker into a breaker compartment for connection of primary contacts of the circuit breaker in a connected position to a main bus. The racking motor is configured to drive a racking linkage for racking the circuit breaker into the breaker compartment when provided with racking power. A single plug is mounted in the circuit breaker and configured to conduct control power by connection to a control power receptacle mounted in the breaker compartment when the racking motor has moved the circuit breaker into the connected position.

It is the object of the invention to provide a circuit breaker and a racking system having reduced maintenance costs.

The above object is solved by the independent claim.

In accordance with one example embodiment described herein, a circuit breaker with an integrated motorized racking mechanism, automatically provides electrical power to the racking motor when the breaker is inserted into the switching cabinet. The racking motor remains powered when the breaker is in either a disconnected position, a testing position, or a fully connected position with the main bus in the switchgear cabinet, without having to manually connect plugs to the source of control power and settings. A racking power plug is mounted within the circuit breaker and is configured to conduct electrical power to the racking motor. A racking power receptacle is mounted at a stationary position in the breaker compartment and is configured to automatically connect with the racking power plug when the circuit breaker is inserted into the breaker compartment. Electrical racking power is provided to the racking motor through the connected racking power plug, which remains connected to the racking power receptacle as the circuit breaker moves during the racking operation. The circuit breaker is configured to move relative to the racking power plug when the racking power plug is connected and stationary relative to the racking power receptacle, while the circuit breaker moves within the breaker compartment during racking operation. The racking power plug remains connected to the racking power receptacle after reaching the connected position of the circuit breaker.

A control power plug is mounted in the circuit breaker and is configured to conduct control power to control circuits in the circuit breaker and to exchange control signals between the control circuits and testing or other equipment. The control power plug is configured to connect to a control power receptacle when the racking motor has racked the circuit breaker into the connected position and the racking operation is completed. The control power plug that is mounted in the circuit breaker moves relative to, and remains disconnected from, the control power receptacle that is mounted in the breaker compartment, while the circuit breaker moves within the breaker compartment during racking operation prior to reaching the connected position, at which point the control power plug becomes connected to the control power receptacle.

In accordance with one example embodiment described herein, a racking system for a circuit breaker comprises:.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein circuit breaker moves relative to the racking power plug when the racking power plug is connected to the stationary racking power receptacle while the circuit breaker moves within the breaker compartment during racking operation, and the racking power plug remains connected to the racking power receptacle after reaching the connected position.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein the control power plug mounted in the circuit breaker moves relative to and remains disconnected from the control power receptacle mounted in the breaker compartment while the circuit breaker moves within the breaker compartment during racking operation prior to reaching the connected position where the control power plug becomes connected to the control power receptacle.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein the racking motor is configured to drive a racking linkage for racking the circuit breaker into the breaker compartment when provided with racking power via the racking power plug and the racking power receptacle.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein the racking power plug is configured to connect to the racking power receptacle when the circuit breaker enters the breaker compartment.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein the control power plug is accessible from outside the breaker compartment when the circuit breaker is drawn out from the breaker compartment.

In accordance with one example embodiment described herein, the racking system for a circuit breaker further comprises:
wherein the connection of the primary contacts of the circuit breaker to the main bus is with primary stabs in the circuit breaker when the racking motor has moved the circuit breaker into the connected position.

According to the invention, a circuit breaker comprises:.

The resulting apparatus and system provide a motorized breaker arrangement that powers-up the motor when the breaker is inserted into the cabinet and remains powered up when the breaker is in either a disconnected position, a test position, or a connected position.

<FIG> illustrates a front, overall view of the example switchgear cabinet <NUM>, example circuit breaker <NUM>, and example racking mechanism <NUM> that is an integral part of the circuit breaker <NUM>.

<FIG> is a side view along the section line <NUM>-<NUM>' of <FIG>, illustrating the example breaker compartment <NUM> of the switchgear cabinet <NUM>, the circuit breaker <NUM>, line side primary contact <NUM>, breaker power connector, primary electrical plug or stabs, to the main line bus <NUM> or connector of the switchgear cabinet, the load side primary contact <NUM>' to the main load bus <NUM>', and the racking mechanism <NUM> that is an integral part of the circuit breaker <NUM>.

<FIG> is a side view along the section line 3A-3A' of <FIG>, of the example circuit breaker102, showing the example racking mechanism <NUM> inside of the circuit breaker <NUM>. The circuit breaker <NUM> is shown as having been initially positioned by a technician at the front entrance <NUM> to the breaker compartment <NUM>. The circuit breaker <NUM> includes a main contacts switch <NUM> connected between the line side primary contact <NUM> and the load side primary contact <NUM>'. After the circuit breaker <NUM> has been racked into the switchgear cabinet <NUM>, the main contacts switch <NUM> is configured to interrupt current flowing from the line side primary contact <NUM> to the load side primary contact <NUM>' in response to a trip signal from the trip logic <NUM> resulting from a fault signal from the current transformers CT, based on the settings stored in the settings memory <NUM>.

The example racking mechanism <NUM> includes a racking motor <NUM> that is configured to drive a mechanical linkage when receiving racking power, to move the circuit breaker <NUM> in the racking operation. An example mechanical linkage may be the racking screw <NUM> that is driven into rotation by the racking motor <NUM> to engage and advance through the threaded anchor <NUM> that is fastened to the bottom of the breaker compartment <NUM>. In a racking operation to move the circuit breaker <NUM> to connect with the line bus and load bus, the racking screw pulls the racking motor <NUM>, and thus the circuit breaker <NUM>, into the breaker compartment <NUM>. In a rack-out operation to disconnect the circuit breaker <NUM> from the line bus and load bus, the racking screw pushes the racking motor <NUM>, and thus the circuit breaker <NUM>, out of the breaker compartment <NUM>.

The example racking power plug <NUM> or first racking power connector is moveably mounted on a platform <NUM> that is fastened on the bottom side of the circuit breaker <NUM>. The racking power plug is configured to conduct racking power and control signals to the racking motor <NUM>.

The example racking power receptacle <NUM> or second racking power connector is mounted at a stationary position on the interior bottom surface of the breaker compartment <NUM>. The racking power receptacle <NUM> is configured to automatically connect with the racking power plug <NUM> when the circuit breaker <NUM> is advanced by the technician into the breaker compartment <NUM>, to provide the racking power to the racking motor <NUM> through the connected racking power plug <NUM>. In a second example embodiment of the racking mechanism <NUM> shown in <FIG>, the auxiliary power receptacle <NUM> and the threaded anchor <NUM> are positioned closer to the front <NUM> of the switchgear cabinet <NUM>, to enable automatically connecting the racking power plug <NUM> to the racking power receptacle <NUM> as soon as the circuit breaker <NUM> is inserted into the breaker compartment <NUM> of the switchgear cabinet <NUM>. In an alternate example embodiment, the connector types of the first racking power connector <NUM> and the second racking power connector <NUM> may be reversed, so that the connector <NUM> is a receptacle-type connector and the connector <NUM> is a plug-type connector. Other types of mating electrical connectors may also be used in alternate embodiments for connectors <NUM> and <NUM>, such as a finger cluster connector mated with a stab connector.

The example control power plug <NUM> or first control power connector is shown mounted in the circuit breaker <NUM> in <FIG>. The control power plug <NUM> remains disconnected from the example control power receptacle <NUM> or second control power connector that is mounted in the breaker compartment <NUM> of the switchgear cabinet <NUM>, while the circuit breaker moves within the breaker compartment during the racking operation. When the control power plug <NUM> reaches the connected position of <FIG>, the control power plug <NUM> becomes connected to the control power receptacle <NUM>. The circuit breaker is shown in the disconnected position in <FIG>, where the control power plug <NUM> is accessible to externally located equipment to conduct control power to control circuits <NUM> in the circuit breaker and to exchange control signals between the control circuits <NUM> and testing or other external equipment. In an alternate example embodiment, the connector types of the first control power connector <NUM> and the second control power connector <NUM> may be reversed, so that the connector <NUM> is a receptacle-type connector and the connector <NUM> is a plug-type connector. Other types of mating electrical connectors may also be used in alternate embodiments for connectors <NUM> and <NUM>, such as a finger cluster connector mated with a stab connector.

The example circuit breaker <NUM> is initially positioned by the technician as shown in <FIG>, just prior to the racking power plug <NUM> connecting to the auxiliary power receptacle <NUM>. As the technician advances the position of the circuit breaker <NUM> into the breaker compartment <NUM>, the racking power plug <NUM> becomes connected to the auxiliary power receptacle <NUM> as shown in <FIG>, and racking power is made available to the racking motor <NUM>. The adjusted position of the breaker by the technician also mates the racking screw <NUM> with the threaded anchor <NUM>, which begins advancing the breaker <NUM> in the motorized racking operation. The racking motor <NUM> begins to advance through the threaded anchor <NUM>, pulling the circuit breaker <NUM> further into the breaker compartment.

<FIG> is a top view of the example platform <NUM> in the circuit breaker <NUM>, showing the example relative positions of the racking power plug <NUM> and the racking power receptacle <NUM> corresponding to <FIG>. The circuit breaker <NUM> is shown as having been initially positioned at the entrance <NUM> to the breaker compartment <NUM>. The slot <NUM> in the platform <NUM> guides the racking power plug <NUM> as it moves with respect to the platform <NUM> while the circuit breaker is racked into the breaker compartment. The figure shows the example retention spring <NUM> mounted on top of the platform <NUM> at the end of the slot <NUM> nearest the racking power receptacle <NUM>, as shown in <FIG>. The retention spring <NUM> temporarily captures the stud <NUM> mounted on the top of the racking power plug <NUM>, which projects upward through the slot <NUM>, to enable the racking power plug <NUM> to travel along with the platform <NUM> as the circuit breaker is inserted into the breaker compartment. When the racking power plug <NUM> comes into contact with the racking power receptacle <NUM>, the contact pins of the racking power plug <NUM> are forced into the corresponding sockets of the racking power receptacle <NUM> as the racking power plug <NUM> continues to approach the racking power receptacle <NUM>, as shown in <FIG> and <FIG>.

<FIG> is a top cross sectional view along the section line <NUM>-5A of <FIG>, showing the first example embodiment of the racking mechanism <NUM> in the circuit breaker <NUM> when it is inserted into the switchgear cabinet <NUM>. The initial positions of the racking power plug <NUM> and the racking power receptacle <NUM> correspond to that shown in <FIG> and <FIG>. In a second example embodiment of the racking mechanism <NUM> shown in <FIG>, the auxiliary power receptacle <NUM> and the threaded anchor <NUM> are positioned closer to the front <NUM> of the switchgear cabinet <NUM>, to enable connecting the racking power plug <NUM> to the racking power receptacle <NUM> as soon as the circuit breaker <NUM> is inserted into the breaker compartment <NUM> of the switchgear cabinet <NUM>.

<FIG> is a side interior view of the example circuit breaker of <FIG>, showing the racking power plug <NUM> connected with its contact pins inserted into the corresponding sockets of to the auxiliary power receptacle <NUM>. The figure shows the position of the circuit breaker <NUM> when the technician has adjusted the position of the breaker to enable the racking power plug <NUM> to automatically connect to the racking power receptacle <NUM>, where it can begin to apply racking power to the racking motor <NUM>. The racking power plug <NUM> remains stationary with respect to the breaker compartment <NUM> as the circuit breaker <NUM> moves with respect to the breaker compartment <NUM>, since the racking power plug <NUM> is now connected to the stationary racking power receptacle <NUM>. The position of the breaker <NUM>, as adjusted by the technician, also mates the racking screw <NUM> with the threaded anchor <NUM>, which begins advancing the breaker <NUM> in the motorized racking operation. The control power plug <NUM> remains disconnected from the control power receptacle <NUM> mounted in the breaker compartment <NUM> of the switchgear cabinet <NUM>, while the circuit breaker moves within the breaker compartment during the racking operation.

<FIG> is a top view of the platform in the circuit breaker, showing the example relative positions of the racking power plug and the racking power receptacle corresponding to <FIG>, as electrical contact is made between the two plugs <NUM> and <NUM> and racking power is provided to the racking motor <NUM>. As the circuit breaker and platform <NUM> are moved by the racking motor <NUM> with respect to the racking power receptacle <NUM>, the stud <NUM> on top of the racking power plug <NUM> is released from the retention spring <NUM>, the racking power plug <NUM> being effectively pushed by the racking power receptacle <NUM> as the racking operation progresses.

<FIG> is a side interior view of the example circuit breaker of <FIG>, showing the racking power plug <NUM> having remained plugged into the stationary racking power receptacle <NUM>, so as to continue powering the racking motor <NUM> while the circuit breaker <NUM> is moved in the racking operation by the racking motor <NUM>. The racking power plug <NUM> is moveably mounted on the platform <NUM> and is guided by the slot <NUM> in the platform <NUM> to move with respect to the platform <NUM> and the circuit breaker's structure, remaining in position in electrical contact with the racking power receptacle <NUM>. The control power plug <NUM> remains disconnected from the control power receptacle <NUM> that is mounted in the breaker compartment <NUM> of the switchgear cabinet <NUM>, while the circuit breaker moves within the breaker compartment during the racking operation.

<FIG> is a top view of the platform in the circuit breaker, showing the example relative positions of the racking power plug and the racking power receptacle corresponding to <FIG>, as the circuit breaker moves during the racking operation. As the circuit breaker and platform <NUM> are moved by the racking motor <NUM>, the racking power plug <NUM> is effectively pushed by the racking power receptacle <NUM> as the racking operation progresses.

<FIG> is a side interior view of the example circuit breaker of <FIG>, showing the racking power plug <NUM> continuing to be plugged into the racking power receptacle <NUM> to continue powering the racking motor <NUM> as the circuit breaker <NUM> becomes fully racked with its line side primary contact <NUM> connected to the main line bus <NUM> and the load side primary contact <NUM>' connected to the main load bus <NUM>'.

The example control power plug <NUM> is configured to connect to the control power receptacle <NUM> when the racking motor <NUM> has racked the circuit breaker <NUM> into the connected position of <FIG> and the racking operation is completed. The control power plug <NUM> and the connected control power receptacle <NUM> form the path to conduct control power to the control circuits <NUM> in the circuit breaker <NUM> and to exchange control signals between the control circuits <NUM> and testing or other equipment. The control power plug <NUM> is also configured to convey signals for settings and other control information to the settings memory <NUM> and the trip logic <NUM>, when it is connected to the control power receptacle <NUM>.

<FIG> is a top view of the platform in the circuit breaker, showing the example relative positions of the racking power plug <NUM> and the racking power receptacle <NUM> corresponding to <FIG> as the circuit breaker becomes fully racked with its primary contacts <NUM> and <NUM>' connecting with the main bus <NUM> and <NUM>'. The connection of the primary contacts of the circuit breaker to the main bus is with a primary electrical plug or stabs in the circuit breaker.

<FIG> is a top cross sectional view along the section line <NUM>-5A of <FIG>, showing the second example embodiment of the racking mechanism <NUM> in the circuit breaker <NUM>, with the racking power receptacle <NUM> and the threaded anchor <NUM> positioned closer to the front <NUM> of the switchgear cabinet <NUM>, to enable connecting the racking power plug <NUM> to the racking power receptacle <NUM> as soon as the circuit breaker <NUM> is inserted into the breaker compartment <NUM> of the switchgear cabinet <NUM>.

<FIG> illustrates an alternate embodiment in a front, overall view of the example switchgear cabinet <NUM>, example circuit breaker <NUM> comprising breaker circuits <NUM> and breaker base <NUM> that is an integral part of the circuit breaker <NUM>.

<FIG> is a side view along the section line <NUM>-<NUM>' of the alternate embodiment of <FIG>, illustrating the example breaker compartment <NUM> of the switchgear cabinet <NUM>, circuit breaker <NUM> comprising breaker circuits <NUM> and breaker base <NUM> that is an integral part of the circuit breaker <NUM>, and primary contacts <NUM> and <NUM>' to the main bus <NUM>, <NUM>'.

<FIG> is a side view along the section line 8A-8A' of the alternate embodiment of <FIG>, of the example circuit breaker <NUM> comprising breaker circuits <NUM> and breaker base <NUM>, inside of the circuit breaker <NUM>. The racking motor <NUM> is fastened to the breaker base <NUM>. The moveable carrier <NUM> is fastened to the bottom of the housing of the breaker circuits <NUM>. The racking screw <NUM> is driven into rotation by the racking motor <NUM> to engage threads within the moveable carrier <NUM> and move the moveable carrier <NUM> and the breaker circuits <NUM> either toward or away from the contact position of the primary contacts <NUM> and <NUM>' to the main bus <NUM>, <NUM>'. The racking power plug <NUM> is fastened to the breaker base <NUM>. The racking power receptacle <NUM> is fastened to the switchgear cabinet <NUM>. The initial position of the racking power plug <NUM> is shown in <FIG> before it connects to the racking power receptacle <NUM> when the circuit breaker <NUM> is initially inserted by a technician into the breaker compartment <NUM>. The control power plug <NUM> is fastened to the top of the housing of the breaker circuits <NUM>. The stationary control power receptacle <NUM> is fastened to the switchgear cabinet <NUM>. The control power plug <NUM> remains disconnected from the stationary control power receptacle <NUM> while the breaker circuits <NUM> of the circuit breaker <NUM> moves within the breaker compartment <NUM> during the racking operation. Upon reaching the connected position of <FIG>, the control power plug <NUM> becomes connected to the stationary control power receptacle <NUM>.

<FIG> is a side interior view of the example circuit breaker <NUM> of the alternate embodiment of <FIG>, showing the position of the circuit breaker <NUM> when the technician has adjusted the position of the breaker base <NUM>, enabling the racking power plug <NUM> to automatically connect to the stationary racking power receptacle <NUM>, where it can begin to apply racking power to the racking motor <NUM>. The breaker base <NUM> may be latched to the switchgear cabinet <NUM> at this point. The racking power plug <NUM> remains stationary with respect to the breaker compartment <NUM> as the breaker circuits <NUM> move with respect to the compartment <NUM>, since the racking power plug <NUM> is now connected to the stationary racking power receptacle <NUM>. The racking screw <NUM> mates with the moveable carrier <NUM>, which begins advancing the breaker circuits <NUM> in the motorized racking operation. The control power plug <NUM> mounted in the moving breaker circuits <NUM>, is shown remaining disconnected from the stationary control power receptacle <NUM>.

<FIG> is a side interior view of the example circuit breaker <NUM> of the alternate embodiment of <FIG> in the connected position, showing the racking power plug <NUM> continuing to be plugged into the racking power receptacle <NUM> to continue powering the racking motor <NUM> as the circuit breaker <NUM> becomes fully racked with its primary contacts <NUM> and <NUM>' connecting with the main bus <NUM> and <NUM>'. The control power plug <NUM> is shown connected to the stationary control power receptacle <NUM> upon reaching the connected position.

<FIG> is a top cross sectional view along the section line <NUM>-9A of the alternate embodiment of <FIG>, showing the first example embodiment of the breaker base <NUM> in the circuit breaker <NUM> when it is inserted into the switchgear cabinet <NUM>, with the position of the racking motor <NUM> close to the front end of the breaker base <NUM> to thereby push the breaker circuits <NUM> toward the connected position of the circuit breaker <NUM>, corresponding to <FIG>.

<FIG> is a top cross sectional view along the section line <NUM>-9A of the alternate embodiment of <FIG>, showing a second example embodiment of the breaker base <NUM> in the circuit breaker <NUM>, with the racking motor <NUM> positioned close to the back end of the breaker base <NUM>, to thereby pull the breaker circuits <NUM> toward the connected position of the circuit breaker <NUM>, corresponding to <FIG>.

The resulting apparatus and system provide a motorized breaker arrangement that powers-up the motor when the breaker is inserted into the cabinet and remains powered up when the breaker is in either a disconnected position or connected position, without having to manually connect plugs.

Claim 1:
A circuit breaker (<NUM>), comprising:
a racking motor (<NUM>) mounted in the circuit breaker (<NUM>), configured to move the circuit breaker (<NUM>) into a breaker compartment (<NUM>) for connection of primary contacts (<NUM>, <NUM>') of the circuit breaker (<NUM>) in a connected position to a main bus (<NUM>), the racking motor (<NUM>) configured to drive a racking linkage (<NUM>) for racking the circuit breaker (<NUM>) into the breaker compartment (<NUM>) when provided with racking power;
a control power plug (<NUM>) mounted in the circuit breaker (<NUM>), configured to conduct control power by connection to a control power receptacle (<NUM>) mounted at a stationary position in the breaker compartment (<NUM>), when the racking motor (<NUM>) has moved the circuit breaker (<NUM>) into the connected position;
a racking power plug (<NUM>) mounted in the circuit breaker (<NUM>), configured to conduct the racking power to the racking motor (<NUM>) by connection to a racking power receptacle (<NUM>) mounted at a stationary position in the breaker compartment (<NUM>);
wherein the racking power plug (<NUM>) is further configured to remain connected and stationary relative to the racking power receptacle (<NUM>) at its stationary position in the breaker compartment while the circuit breaker (<NUM>) moves within the breaker compartment (<NUM>) during the racking operation and after the circuit breaker (<NUM>) reaches the connected position.