EP4702585A1

EP4702585A1 - Mechanical advantage contact opening mechanism for circuit interrupters

Info

Publication number: EP4702585A1
Application number: EP24723628.4A
Authority: EP
Inventors: Tyler Holp; David R. Rohn
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2023-04-28
Filing date: 2024-04-24
Publication date: 2026-03-04
Also published as: WO2024224318A1; MX2025012637A; CN120883309A

Abstract

An actuator for a circuit interrupter utilizes a lever to open the separable contacts of each pole assembly. The lever is coupled at a first end to a conductive plate of a Thomson coil arrangement and coupled at a second end to a movable electrode stem. The lever rotates about a pivot, and the pivot is positioned closer to the first end of the lever than the second end. The distance L1 between the first end of the lever and the pivot is shorter than the distance L2 between the pivot and the second end. When the movable electrode stem is in the closed state and the Thomson coil is activated, the conductive plate moves away from the Thomson coil at a velocity v1, and the movable electrode stem separates from the fixed electrode stem at a velocity v2 that is greater than v1 by a factor of L2/L1.

Description

MECHANICAL ADVANTAGE CONTACT OPENING MECHANISM FOR CIRCUIT

INTERRUPTERS

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application Serial No. 63/462,616, filed on April 28, 2023 and titled “MECHANICAL ADVANTAGE CONTACT OPENING MECHANISM FOR CIRCUIT INTERRUPTERS” the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION:

[0002] The disclosed concept relates generally to circuit interrupters, and in particular, to actuation mechanisms used to open and close separable contacts in circuit interrupters.

BACKGROUND OF THE INVENTION:

[0003] Circuit interrupters, such as for example and without limitation, those used in circuit breakers, are typically used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload condition, a short circuit, or another fault condition, such as an arc fault or a ground fault. Circuit interrupters typically include mechanically separable electrical contacts, which operate as a switch. When the separable contacts are in contact with one another in a closed state, current is able to flow through any circuits connected to the circuit interrupter. When the separable contacts are isolated from one another in an open state, current is prevented from flowing through any circuits connected to the circuit interrupter. The separable contacts may be operated either electrically by way of remote input, manually by way of an operator handle, or automatically in response to a detected fault condition. Typically, such circuit interrupters include an actuator designed to rapidly close or open the separable contacts, and a trip mechanism, such as a trip unit, which senses a number of fault conditions to trip the separable contacts open automatically using the actuator. Upon sensing a fault condition, the trip unit trips the actuator to move the separable contacts to their open position.

[0004] Hybrid circuit interrupters employ a power electronic interrupter in addition to the mechanical separable contacts, and traditionally use a vacuum interrupter (wherein the mechanical separable contacts are housed in a vacuum housing) to carry continuous current. The power electronic interrupter is connected in parallel with the mechanical contacts, and comprises electronics structured to commutate current after a fault is detected. Once current is commutated from the mechanical switch to the power electronic interrupter, the mechanical separable contacts are able to separate with a reduced risk of arcing. It is advantageous to commutate as much current as possible to the electronic branch as quickly as possible and to open the mechanical separable contacts at high speeds in order to limit the let- through current during a fault condition.

[0005] The mechanical separable contacts typically comprise one stationary contact disposed at the end of a stationary electrode stem, and one movable contact disposed at the end of a movable electrode stem, with the movable electrode stem being a component of a larger movable conductor assembly. The force required to open mechanical separable contacts quickly can be significant due to the mass of the movable conductor assembly that must be driven open in order to separate the separable contacts during a fault condition. Thomson coil actuators are noted for their ability to open mechanical separable contacts at very high speeds, and are typically employed in hybrid circuit interrupters. When a hybrid circuit breaker is scaled for use at higher current ratings, the movable mass of the vacuum interrupter is increased inherently, making it more difficult to open the vacuum interrupter rapidly. Likewise, as a hybrid circuit breaker is used at higher voltage ratings, the vacuum interrupter movable electrode stem must be opened a greater distance to gain the necessary dielectric strength during fault interruption. Because the lapse of any time between the occurrence of a fault condition and the opening of the mechanical separable contacts leads to at least some current passing through the mechanical separable contacts, there is always a need for actuators that can open mechanical separable contacts at higher speeds than available actuators can.

[0006] There is thus room for improvement in mechanisms used to open separable contacts in circuit interrupters such as hybrid circuit interrupters.

SUMMARY OF THE INVENTION:

[0007] These needs, and others, are met by an actuating arrangement for a circuit interrupter in which, for each pole assembly of the circuit interrupter, a lever is operably coupled at one end to a conductive plate of a Thomson coil arrangement and at the other end to a movable electrode stem.

[0008] In one aspect of the disclosed concept, a single-pole actuator is structured for use with a pole assembly of a circuit interrupter. The pole assembly comprises a fixed electrode stem and a movable electrode stem, the movable electrode stem being configured to move between a closed state and an open state, the movable electrode stem being electrically connected to the fixed electrode stem in the closed state and being electrically isolated from the fixed electrode stem in the open state. The single-pole actuator comprises: a Thomson coil arrangement; a lever having a first end and a second end disposed opposite the first end; a pivot; and an electrode-coupling shaft. The Thomson coil arrangement includes: a conductive coil configured to be activated by a current source, and a conductive plate positioned adjacent the conductive coil. The lever is configured to rotate about the pivot. The conductive plate is coupled to the first end of the lever. The electrode-coupling shaft is coupled to the second end of the lever and is structured to be coupled to the movable electrode stem of the circuit interrupter. The single-pole actuator is configured such that, when the conductive plate is adjacent the conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second end of the lever to move in a second direction, the second direction being opposite the first direction.

[0009] In another aspect of the disclosed concept, a multi-pole actuator is structured for use with a circuit interrupter. The circuit interrupter includes a plurality of pole assemblies, each pole assembly comprising a fixed electrode stem and a corresponding movable electrode stem, each movable electrode stem being configured to move between a closed state and an open state such that each movable electrode stem is electrically connected to the corresponding fixed electrode stem in the closed state and such that each movable electrode stem is electrically isolated from the corresponding fixed electrode stem in the open state. The multi-pole actuator comprises: a number of Thomson coil arrangements, the number of Thomson coil arrangements being fewer in number than the plurality of pole assemblies; a plurality of levers, the plurality of levers being double the number of Thomson coil arrangements; a plurality of pivots equal in number to the plurality of levers; and a plurality of electrode-coupling shafts, the plurality of electrode-coupling shafts being equal in number to the plurality of pole assemblies. Each Thomson coil arrangement includes: a conductive coil configured to be activated by a current source, and a conductive plate positioned adjacent the conductive coil. Each lever has a first end and a second end disposed opposite the first end. Each lever is configured to rotate about a corresponding one of the pivots. Each conductive plate is coupled to the first ends of two of the levers. Each electrode-coupling shaft is coupled to the second end of at least one of the levers and is structured to be coupled to one of the movable electrode stems of the circuit interrupter. The multi-pole actuator is configured such that, for each Thomson coil arrangement, when the conductive plate is adjacent the conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second ends of the two levers coupled to the conductive plate to move in a second direction, the second direction being opposite the first direction.

[0010] In another aspect of the disclosed concept, a circuit interrupter comprises a number of pole assemblies and a mechanical advantage actuator. Each pole assembly includes a fixed electrode stem and a movable electrode stem. The movable electrode stem is configured to move between a closed state and an open state, with the movable electrode stem being electrically connected to the fixed electrode stem in the closed state and being electrically isolated from the fixed electrode stem in the open state. The mechanical advantage actuator comprises: a number of Thomson coil arrangements; a number of levers, each lever having a first end and a second end disposed opposite the first end; a number of pivots corresponding in number to the number of levers; and a number of electrode-coupling shafts corresponding in number to the number of pole assemblies. Each Thomson coil arrangement includes: a conductive coil configured to be activated by a current source, and a conductive plate positioned adjacent the conductive coil. Each lever is configured to rotate about a corresponding one of the pivots. The first end of each lever is coupled to at least one of the conductive plates. The second end of each lever is coupled to one of the electrode stems. The mechanical advantage actuator is structured such that, for each lever and for each conductive plate coupled to the lever, when the conductive plate is adjacent its corresponding conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second end of each lever coupled to the conductive plate to move in a second direction, the second direction being opposite the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0011] A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

[0012] FIG. 1 is schematic diagram of a single-pole hybrid circuit interrupter;

[0013] FIG. 2A is a partial sectional side view of a single-pole mechanical advantage actuator for a single pole circuit interrupter such as the hybrid circuit interrupter depicted in FIG. 1, with the separable contacts in a closed state, in accordance with example embodiments of the disclosed concept;

[0014] FIG. 2B shows the partial sectional side view of the single-pole mechanical advantage actuator shown in FIG. 2A, with the separable contacts in an open state, [0015] FIG. 3 is a schematic diagram of a multi-pole hybrid circuit interrupter in which a single actuator is used to simultaneously open the separable contacts of all poles, in accordance with an example embodiment of the disclosed concept; and

[0016] FIG. 4A is a partial sectional side view of a multi-pole mechanical advantage actuator for a multi-pole circuit interrupter such as the hybrid circuit interrupter depicted in FIG. 3, with the separable contacts in a closed state, in accordance with example embodiments of the disclosed concept; and

[0017] FIG. 4B shows the partial sectional side view of a multi-pole mechanical advantage actuator shown in FIG. 4A, with the separable contacts in an open state.

DETAILED DESCRIPTION OF THE INVENTION:

[0018] Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein.

[0019] As employed herein, the statement that two or more parts or components are “coupled” shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, so long as a link occurs. As used herein, “directly coupled” means that two elements are directly in contact with each other.

As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other.

[0020] As employed herein, when ordinal terms such as “first” and “second” are used to modify a noun, such use is simply intended to distinguish one item from another, and is not intended to require a sequential order unless specifically stated.

[0021] As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).

[0022] As employed herein, the term “processing unit” or “processor” shall mean a programmable analog and/or digital device that can store, retrieve, and process data; a microprocessor; a microcontroller; a microcomputer; a central processing unit; or any suitable processing device or apparatus.

[0023] FIG. 1 is a schematic diagram of a single-pole hybrid circuit interrupter 1, in accordance with an example embodiment of the disclosed concept. The hybrid circuit interrupter 1 (e.g., without limitation, a circuit breaker or switch) includes a pole assembly 2 for a single phase of power that is structured to be electrically connected between a power source 3 and a load 4 via a line conductor 5. The circuit interrupter 1 is structured to trip open or switch open to interrupt current flowing between the power source 3 and load 4 in the event of a fault condition (e.g., without limitation, an overcurrent condition) to protect the load 4, circuitry associated with the load 4, as well as the power source 3. The pole assembly 2 includes a hybrid switch assembly 6 and an actuator 7, and the circuit interrupter 1 includes an electronic trip unit 8. The hybrid switch assembly 6 comprises a set of mechanical separable contacts 10 and a power electronic interrupter 12. It is noted that the hybrid switch assembly 6 in FIG. 1 is a simplified depiction of a hybrid switch intended to demonstrate how current commutates past mechanical separable contacts in a hybrid switch, and is not intended to be limiting on the different types of hybrid switch assemblies that can be included in a hybrid circuit interrupter 1. The trip unit 8 is structured to monitor power flowing through the pole assembly 2 via a current sensor 14 and/or other sensors and to detect fault conditions based on the power flowing through the pole assembly 2.

[0024] Under normal operating conditions, the mechanical contacts 10 are in a closed state such that they are in contact with one another, enabling current to flow from the power source 3 through the line conductor 5 and the mechanical contacts 10 to the load 4. In addition, the power electronic interrupter 12 is powered off under normal operating conditions, such that current cannot flow through the power electronic interrupter 12. In response to detecting a fault condition, the trip unit 8 is configured to output a first signal to the power electronic interrupter 12 to power on the power electronic interrupter 12, and to output a second signal to the actuator 7 that causes the actuator 7 to open the mechanical contacts 10.

[0025] The transmission of the second signal from the trip unit 8 to the actuator 7 to open the mechanical contacts 10 commutates the current, i.e. forces the current to pass through the power electronic interrupter 12, as current will not flow through the power electronic interrupter 12 until the mechanical contacts 10 start to separate. The faster the mechanical contacts 10 separate, the lower the fault current flow through the power electronic interrupter 12 will be. The power electronic interrupter 12 is powered off shortly after commutation in order to fully interrupt the flow of current.

[0026] Reference is now made to FIG. 2A and FIG. 2B, which respectively depict the closed state and the open state of a single-pole mechanical advantage actuator 100 (sometimes referred to hereinafter as the “single-pole actuator 100” for brevity) that can be used with a single-pole circuit interrupter such as the hybrid circuit interrupter 1 shown in FIG.l, in accordance with an example embodiment of the disclosed concept. The single-pole mechanical advantage actuator 100 corresponds to and is a specific embodiment of the schematically depicted actuator 7 shown in FIG. 1, and is depicted being operatively coupled to the mechanical separable contacts 10 that are schematically depicted in FIG. 1. In FIGS. 2A-2B, the separable contacts 10 include both a fixed separable contact 15 and a movable separable contact 16, with the fixed separable contact 15 being disposed at the end of a fixed electrode stem 17 and the movable separable contact 16 being disposed at the end of a movable electrode stem 18.

[0027] The single-pole actuator 100 and its components can be referred to as being in the “closed state” when the separable contacts 10 are closed, and can be referred to as being in the “open state” when the separable contacts 10 are open. An operation that results in the single-pole actuator 100 moving from the closed state to the open state is referred to as an “opening stroke”. It is further noted that movement of any component of the single-pole actuator 100 toward the fixed electrode stem 17 can be described as “proximal” movement, and that movement of any component of the single-pole actuator 100 away from the fixed electrode stem 17 can be described as “distal” movement.

[0028] The single-pole actuator 100 includes one Thomson coil arrangement 101 operatively coupled to a mechanical lever 102 that is configured to rotate about a pivot 103. The Thomson coil arrangement 101 includes a conductive coil 104 fixed in position and a conductive plate 105 configured such that, when the single-pole actuator 100 is in the closed state, the conductive plate 105 moves in the proximal direction away from the coil 104 (i.e. moves upward, relative to the view shown in FIG. 2A) in response to current being supplied to the coil 104, as a result of opposing magnetic fields being generated in the coil 104 and the conductive plate 105 when there is current flow through the coil 104. The circuit interrupter 1 is configured to cause current to be supplied to the coil 104 in response to the trip unit 8 detecting a fault condition. A first shaft 111 couples a first end 112 of the lever 102 to the conductive plate 105, and a second shaft 114 couples a second end 115 of the lever 102 to the movable electrode stem 18. The lever 102 is positioned on the pivot 103 such that a length LI from the lever first end 112 to the pivot 103 is shorter than a second length L2 from the pivot 103 to the lever second end 115.

[0029] The movement of the conductive plate 105 away from the coil 104 during an opening stroke causes the lever first end 112 to also move in the same direction as the conductive plate 105 (i.e. the proximal direction, which is upward relative to the view shown in FIG. 2A) and in turn moves the lever second end 115 in the opposite direction (in the distal direction, which is downward, relative to the view shown in FIG. 2A), due to the rotation of the lever 102 about the pivot 103. Referencing the directional orientations shown in FIGS. 2A-2B, the difference in the lengths LI and L2 produces a mechanical advantage that results in the speed at which the conductive plate 105 moves proximally/upward being amplified relative to the speed at which the movable electrode stem 18 and movable separable contact 16 move distally/downward away from the fixed electrode stem 15 during an opening stroke. Specifically, the speed at which the movable electrode stem 18 and movable separable contact 16 move distally/downward is the product of the speed at which the conductive plate 105 moves proximally/upward and the ratio of length L2 to length LI. In one non-limiting example, referencing the two lengths LI and L2 labeled in FIGS. 2A and 2B, if length LI is one inch and length L2 is two inches such that the ratio of L2 to LI equals two, then the speed at which the movable electrode stem 18 and movable separable contact 16 move distally/downward is two times the speed at which the conductive plate 105 moves proximally/upward .

[0030] Reference is now made to FIG. 3 and FIGS. 4A-4B. FIG. 3 is a schematic diagram of a multi -pole hybrid circuit interrupter 1' in which a single actuator is structured to open the separable contacts of all poles in the circuit interrupter simultaneously, in accordance with an example embodiment of the disclosed concept. FIG. 4A and FIG. 4B respectively depict the closed state and the open state of a multi-pole mechanical advantage actuator 200 (sometimes referred to hereinafter as the “multi-pole actuator 200” for brevity) that can be used with the circuit interrupter 1' of FIG. 3, in accordance with an example embodiment of the disclosed concept. More specifically, the multi-pole actuator 200 shown in FIGS. 4A-4B corresponds to and is a specific embodiment of a multi-pole actuator 27 schematically depicted in FIG. 3.

[0031] The circuit interrupter 1' shown in FIG. 3 includes nearly all of the same components of the circuit interrupter 1 shown in FIG. 1, except that the circuit interrupter 1' includes a single actuator 27 that simultaneously actuates multiple pole assemblies 2' instead of including an actuator 7 that only actuates a single pole assembly 2 as the circuit interrupter 1 does. While only the pole assembly 2' for phase A (corresponding to line conductor A) is shown in detail in FIG. 3 for ease of illustration, it is noted that the respective pole assemblies 2' for phases B and C (corresponding to the line conductors B and C) are functionally identical to the pole assembly 2' for phase A. The actuator 27 of the circuit interrupter 1' is common to all of the pole assemblies 2' in the circuit interrupter 1' and simultaneously actuates all of the separable contacts 10' of all pole assemblies 2' within the circuit interrupter 1'. Aside from the actuator 27 of the circuit interrupter l'(FIG. 3) being structured to actuate multiple pole assemblies rather than only being structured to actuate a single pole assembly as the actuator 7 of the circuit interrupter 1 is (FIG. 1), the components of the circuit interrupter 1' (FIG. 3) correspond to and are functionally equivalent to the components included in the circuit interrupter 1 (FIG. 1). Accordingly, every component of the circuit interrupter 1' (FIG. 3) that is structurally and functionally equivalent to a corresponding component of the circuit interrupter 1 (FIG. 1) is numbered with the same reference number used for the corresponding component of circuit interrupter 1, with the addition of a prime symbol (i.e. ' ).

[0032] The multi-pole actuator 200 and its components can be referred to as being in the “closed state” when the separable contacts 10' of all three pole assemblies 2' are closed, and can be referred to as being in the “open state” when the separable contacts 10' of all three pole assemblies 2' are open. Due to the actuator 27 being common to all of the pole assemblies 2', when the electronic trip unit 8' of the circuit interrupter 1' detects a fault in any phase, the trip unit 8' first causes the power electronic interrupters 12' of all phases’ pole assemblies 2' to be powered on, then causes the single actuator 27 to open the separable contacts 10' of all pole assemblies 2' simultaneously in order to commutate the current in each phase to that phase’s power electronic interrupter 12', and lastly causes all of the phases’ power electronic interrupters 12' to be powered off in order to fully interrupt all current within the circuit interrupter 1'.

[0033] In FIGS. 4A-4B, three identical pole assemblies 2'A, 2'B, and 2'C are shown, which are embodiments of the pole assemblies 2' shown in FIG. 3. In FIGS. 4A-4B, each set of separable contacts 10' includes both a fixed separable contact 15' and a movable separable contact 16', with the fixed separable contact 15' being disposed at the end of a fixed electrode stem 17' and the movable separable contact 16' being disposed at the end of a movable electrode stem 18'. While three pole assemblies 2'A, 2'B, and 2'C are depicted in FIG. 4, it will be apparent from the following description that the multi-pole actuator 200 can be adapted to simultaneously open the separable contacts of more than three poles or only two poles without departing from the scope of the disclosed concept.

[0034] An operation that results in the multi-pole actuator 200 moving from the closed state to the open state is referred to as an “opening stroke”. Movement of any component of the multi -pole actuator 200 toward the fixed electrode stems 17' can be described as “proximal” movement, and movement of any component of the multi-pole actuator 200 away from the fixed electrode stems 17' can be described as “distal” movement. [0035] The pole assemblies 2'A, 2'B, and 2'C and their components are sometimes referred to hereinafter generally, either collectively or individually, by omitting the letters from the reference numbers (e.g. “the pole assemblies 2' ” or “the pole assembly 2' ”).

Because the components of all three pole assemblies 2' are the same, the components of each pole assembly 2' are referred to with reference numbers that omit the letter corresponding to the specific pole assembly, i.e. “A”, “B”, or “C”.

[0036] The multi -pole actuator 200 includes a plurality of Thomson coil arrangements

201, with each Thomson coil arrangement 201 being structured to actuate two mechanical levers 202, and with each mechanical lever 202 being configured to rotate about a pivot 203. It is noted that the multi-pole actuator 200 includes one fewer Thomson coil arrangement 201 than there are pole assemblies 2'. Thus, while the multi-pole actuator 200 is shown including two Thomson coil arrangements 201 in FIG. 4 due to there being three pole assemblies 2' in FIG. 4, it is noted that the multi-pole actuator 200 adapted for use with a two-pole circuit interrupter 1' would include only one Thomson coil arrangement 201 and that a multi -pole actuator 200 adapted for use with a circuit interrupter 1 ' that includes more than three pole assemblies 2' would include more than two Thomson coil arrangements 201.

[0037] Each Thomson coil arrangement 201 includes a conductive coil 204 fixed in position and a conductive plate 205 configured such that, when the multi-pole actuator 200 is in the closed state, the conductive plate 205 moves in the proximal direction away from the coil 204 (i.e. moves upward, relative to the view shown in FIG. 4A) in response to current being supplied to the coil 204, as a result of opposing magnetic fields being generated in the coil 204 and the conductive plate 205 when there is current flow through the coil 204. The circuit interrupter 1' is configured to cause current to be supplied to all coils 204 in response to the trip unit 8' detecting a fault condition in any of the power phases. Relative to a lateral dimension 401 (as indicated by the arrow 401 in FIGS. 4A and 4B), each Thomson coil arrangement 201 is positioned laterally between two pole assemblies 2'.

[0038] For each given conductive plate 205, there is a plate -coupling shaft 211 coupled to the conductive plate 205 and coupled to a first end 212 of each of the two levers 202 to which the conductive plate 205 is coupled. An electrode-coupling shaft 214 couples a second end 215 of each lever 202 to a movable electrode stem 18' of one of the pole assemblies 2'. Each lever 202 is positioned on its pivot 203 such that a length LI from the lever first end 212 to the pivot 203 is shorter than a second length L2 from the pivot 203 to the lever second end 215.

[0039] The movement of the conductive plates 205 away from their corresponding coils 204 during an opening stroke causes the lever first ends 212 to move in the same direction as the conductive plates 205 (i.e. the proximal direction, which is upward relative to the view shown in FIG. 4A) and in turn moves the lever second ends 215 in the opposite direction (in the distal direction, which is downward relative to the view shown in FIG. 4A), due to the rotation of each lever 202 about its pivot 203. Referencing the directional orientations shown in FIGS. 4A-4B, the difference in the lengths LI and L2 produces a mechanical advantage that results in the speed at which the conductive plates 205 move proximally/upward being amplified with respect to the speed at which the corresponding movable electrode stems 18' and movable separable contacts 16' move distally/downward away from the fixed electrode stems 15' during an opening stroke. Specifically, the speed at which the movable electrode stems 18' and movable separable contacts 16' move distally/downward is the product of the speed at which the conductive plates 205 move proximally/upward and the ratio of length L2 to length LI, as previously described herein in conjunction with the single-pole actuator 100 shown in FIGS. 2A-2B. As such, in one nonlimiting example, and referencing the two lengths LI and L2 labeled in FIGS. 4A and 4B, if length LI is one inch and length L2 is two inches such that the ratio of L2 to LI equals two, then the speed at which the movable electrode stems 18' and movable separable contacts 16' move distally/downward is two times the speed at which the conductive plate 205 move proximally/upward .

[0040] It is noted that there is increased reliability in the B power phase (i.e. the phase of pole assembly 2'B) of the circuit interrupter 1' due to the redundancy of the movable electrode stem 18' in the B phase being coupled to two levers 202 instead of just one. In addition, it is noted that known multi-pole circuit interrupters utilize an individual actuator for each pole assembly such that each given pole assembly includes its own individual actuator that only actuates the movable electrode stem within that given pole assembly and is operated independently of every other pole assembly’s actuator. That is, in known multi-pole circuit interrupters, there is a one-to-one ratio of actuators (e.g. Thomson coil arrangements 201) to pole assemblies. The multi-pole actuator 200 represents an improvement over such known systems, as the fewer number of actuators (i.e. Thomson coil arrangements 201) relative to the number of pole assemblies 2' results in reduced cost and complexity as compared to known systems that utilize a one-to-one ratio of actuators to pole assemblies. [0041] Both the single pole actuator 100 and the multi -pole actuator 200 provide improvements over existing single pole and multi-pole actuators that are configured to cause movable electrode stems to move in the same direction as the conductive plate of a Thomson coil arrangement, because the use of the levers 102,202 in the disclosed actuators 100,200 enables the movable electrode stems 18,18' and movable separable contacts 16,16' to move at a greater velocity than the conductive plates 105,205 during an opening stroke rather than at the same velocity. In FIGS. 2A-2B and in FIGS. 4A-4B, contact springs (unnumbered in the figures) are provided below each movable electrode stem 18,18', in order to bias the movable electrode stem 18,18' to the closed position in the absence of any force being exerted by the Thomson coil arrangement(s) 101, 201. Contact springs are often included in circuit interrupters in order to meet the short-circuit rating of the breaker. That is, the higher the short-circuit rating, the higher the contact force provided by the contact spring needs to be, and the higher the contact force provided by the contact spring is, the more force/energy needs to be generated by the Thomson Coil arrangement 101,201 to actuate the movable electrode stem 18,18' during an opening stroke. It will be appreciated that the amplification of the velocity of each movable electrode stem 18,18' due to the use of each lever 102, 202 during an opening stroke in the mechanical advantage actuators 100,200 significantly assists in producing the necessary force/energy needed to overcome the contact force of the contact spring.

[0042] While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.

Claims

What is claimed is:

1. A single-pole actuator for use with a pole assembly of a circuit interrupter, the pole assembly comprising a fixed electrode stem and a movable electrode stem, the movable electrode stem being configured to move between a closed state and an open state, the movable electrode stem being electrically connected to the fixed electrode stem in the closed state and being electrically isolated from the fixed electrode stem in the open state, the single-pole actuator comprising: a Thomson coil arrangement, the Thomson coil arrangement comprising: a conductive coil configured to be activated by a current source; and a conductive plate positioned adjacent the conductive coil; a lever, the lever having a first end and a second end disposed opposite the first end; a pivot; and an electrode-coupling shaft, wherein the lever is configured to rotate about the pivot, wherein the conductive plate is coupled to the first end of the lever, wherein the electrode-coupling shaft is coupled to the second end of the lever and is structured to be coupled to the movable electrode stem of the circuit interrupter, wherein the single-pole actuator is configured such that, when the conductive plate is adjacent the conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second end of the lever to move in a second direction, the second direction being opposite the first direction.

2. The single-pole actuator of claim 1, wherein the lever and the pivot are configured to position the movable electrode stem in the closed state when the conductive plate is adjacent to the conductive coil.

3. The single-pole actuator of claim 2, wherein the first direction is a proximal direction, the proximal direction being oriented toward the fixed electrode stem, and wherein the second direction is a distal direction, the distal direction being oriented away from the fixed electrode stem.

4. The single-pole actuator of claim 1, wherein the pivot is positioned closer to the first end of the lever than to the second end of the lever.

5. The single-pole actuator of claim 2, wherein the pivot is positioned closer to the first end of the lever than to the second end of the lever.

6. A multi-pole actuator for use with a circuit interrupter, the circuit interrupter including a plurality of pole assemblies, each pole assembly comprising a fixed electrode stem and a corresponding movable electrode stem, each movable electrode stem being configured to move between a closed state and an open state such that each movable electrode stem is electrically connected to the corresponding fixed electrode stem in the closed state and such that each movable electrode stem is electrically isolated from the corresponding fixed electrode stem in the open state, the multi-pole actuator comprising: a number of Thomson coil arrangements, the number of Thomson coil arrangements being fewer in number than the plurality of pole assemblies, each Thomson coil arrangement comprising: a conductive coil configured to be activated by a current source; and a conductive plate positioned adjacent the conductive coil; a plurality of levers, the plurality of levers being double the number of Thomson coil arrangements, each lever having a first end and a second end disposed opposite the first end; a plurality of pivots equal in number to the plurality of levers; and a plurality of electrode-coupling shafts, the plurality of electrode-coupling shafts being equal in number to the plurality of pole assemblies, wherein each lever is configured to rotate about a corresponding one of the pivots, wherein each conductive plate is coupled to the first ends of two of the levers, wherein each electrode-coupling shaft is coupled to the second end of at least one of the levers and is structured to be coupled to one of the movable electrode stems of the circuit interrupter, wherein the multi-pole actuator is configured such that, for each Thomson coil arrangement, when the conductive plate is adjacent the conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second ends of the two levers coupled to the conductive plate to move in a second direction, the second direction being opposite the first direction.

7. The multi-pole actuator of claim 6, wherein, for each lever, its corresponding pivot, each electrode-coupling shaft coupled to the lever, and each conductive plate coupled to the lever: when each electrode-coupling shaft is coupled to one of the movable electrode stems of the circuit interrupter, the lever and its corresponding pivot are configured to position the movable electrode stem in the closed state when each conductive plate is adjacent to its corresponding conductive coil.

8. The multi-pole actuator of claim 6, wherein the first direction is a proximal direction, the proximal direction being oriented toward the fixed electrode stems, and wherein the second direction is a distal direction, the distal direction being oriented away from the fixed electrode stems.

9. The multi-pole actuator of claim 6, wherein, for each pivot and its corresponding lever, the pivot is positioned closer to the first end of the lever than to the second end of the lever.

10. The multi-pole actuator of claim 7, wherein, for each pivot and its corresponding lever, the pivot is positioned closer to the first end of the lever than to the second end of the lever.

11. A circuit interrupter, the circuit interrupter comprising: a number of pole assemblies, each pole assembly comprising: a fixed electrode stem; and a movable electrode stem, the movable electrode stem being configured to move between a closed state and an open state, the movable electrode stem being electrically connected to the fixed electrode stem in the closed state and being electrically isolated from the fixed electrode stem in the open state; and a mechanical advantage actuator, the mechanical advantage actuator comprising: a number of Thomson coil arrangements, each Thomson coil arrangement comprising: a conductive coil configured to be activated by a current source; and a conductive plate positioned adjacent the conductive coil; a number of levers, each lever having a first end and a second end disposed opposite the first end; a number of pivots corresponding in number to the number of levers; and a number of electrode-coupling shafts corresponding in number to the number of pole assemblies, wherein each lever is configured to rotate about a corresponding one of the pivots, wherein the first end of each lever is coupled to at least one of the conductive plates, wherein the second end of each lever is coupled to one of the electrode stems, wherein the mechanical advantage actuator is structured such that, for each lever and for each conductive plate coupled to the lever, when the conductive plate is adjacent its corresponding conductive coil and the conductive coil is activated with current: the conductive coil repels the conductive plate in a first direction, and movement of the conductive plate in the first direction causes the second end of each lever coupled to the conductive plate to move in a second direction, the second direction being opposite the first direction.

12. The circuit interrupter of claim 11, further comprising: a trip unit, the trip unit being configured to monitor current flowing through each pole assembly, wherein the number of pole assemblies is two or more, wherein each conductive plate is coupled to the first ends of two of the levers, and wherein the trip unit is configured to simultaneously activate the conductive coil of all of the Thomson coil arrangements upon detection of a fault current.

13. The circuit interrupter of claim 11, wherein, for each lever, its corresponding pivot, the electrode-coupling shaft coupled to the lever, the movable electrode stem coupled to the electrode-coupling shaft, and the conductive plate coupled to the lever: the lever and its corresponding pivot are configured to position the movable electrode stem in the closed state when the conductive plate is adjacent to its corresponding conductive coil.

14. The circuit interrupter of claim 11 , wherein the first direction is a proximal direction, the proximal direction being oriented toward each fixed electrode stem, and wherein the second direction is a distal direction, the distal direction being oriented away from each fixed electrode stem.

15. The circuit interrupter of claim 11, wherein, for each pivot and its corresponding lever, the pivot is positioned closer to the first end of the lever than to the second end of the lever.

16. The circuit interrupter of claim 13, wherein, for each pivot and its corresponding lever, the pivot is positioned closer to the first end of the lever than to the second end of the lever.