Low resistance power connector

Abstract

A low resistance connector for a power connection system. The connector has a trunk configured to be attached to the circuit breaker, first and second ribs protruding from the trunk, and first and second conductive springs. The ribs define a slot therebetween, and each rib has its opposing slot-facing surfaces. A surface of the rib facing the slot has a channel formed therein in which the spring is positioned. The slot is configured to receive a tab of the power connector such that the spring is biased against the tab when the tab is received within the slot.

Description

Technical Field

[0001] This disclosure generally relates to power distribution equipment and systems, and more specifically, to low-resistance power connections for connecting air circuit breaker (ACB) clusters, molded case circuit breakers (MCCBs), etc., to electrical busbars or for other electrical connections. Background Technology

[0002] Circuit breakers are most commonly used to protect electrical equipment from overload and short-circuit events. Large circuit breakers carrying thousands of amperes of current are typically housed within metal-cased switchgear assemblies. The switchgear assembly is connected to large electrical conductors called busbars, which carry current from a power source (such as an electrical installation) through the installed circuit breaker to the load protected by the circuit breaker. During installation, the circuit breaker, typically weighing hundreds of pounds, is lifted into the switchgear assembly and pushed into place by mounting it in a withdrawable bracket or base configured to receive the circuit breaker. Once pushed into the switchgear assembly, the circuit breaker completes the circuit to be protected.

[0003] For example, a withdrawable ACB has a fixed withdrawable bracket and a removable circuit breaker body. The withdrawable bracket is attached to the cabinet of the switchgear assembly and is adapted to receive and support the circuit breaker body. The bracket has multiple conductive electrical connectors that connect to one or more busbars extending into the bracket. When the circuit breaker body is pushed into the bracket, the cluster-type connectors at the rear of the circuit breaker engage the electrical connectors. In this way, the electrical connectors electrically connect the circuit breaker to the circuit to be protected.

[0004] The most common conventional method for achieving this withdrawable electrical connection is to use a cluster design, which consists of several laminated copper fingers. This design has two joints. At the first joint, the cluster is mounted on a cylindrical mount attached to the circuit breaker body, which allows the cluster to pivot. The pivot allows the cluster to self-align at the second sliding joint (to the mating tab of the power connector). This design allows for lateral misalignment between the circuit breaker and the receiving tab. It also allows for tolerance superposition in how far the cluster is pushed onto the receiving tab. The disadvantage of the conventional cluster method is that the contact area is limited and only three contact points are shared for the electrical connection (e.g., two contact points at the first joint, namely, 1) the contact point between the cylindrical feature of the finger and the cluster finger pivot, and 2) the contact point at the location of the cluster engagement pivot, which depends on feature size, alignment, variations in the leaf spring force of the fingers, and alignment of the circuit breaker body and the bracket; and one contact point at the second joint, where the cluster engages the tab). The additional resistance of this design is approximately equal to the resistance of the main contacts inside the circuit breaker itself.

[0005] Furthermore, traditional connector designs generate excessive heat. One solution to address overheating is to increase the number of fingers, but this unnecessarily increases the circuit breaker's footprint. Alternatively, forced convection (fans) can be used to reduce heat in the system, but this solution carries an unacceptable risk of fan failure and does not reduce the system's power consumption.

[0006] Commonly assigned U.S. Patent Application Publication No. 2016 / 0020052 and U.S. Patent No. 8,730,652 disclose known power connection systems for connecting circuit breakers to electrical buses using a cluster design, the entire contents of which are incorporated herein by reference. Summary of the Invention

[0007] Various aspects of this disclosure reduce the space occupied by low-voltage circuit breakers and other equipment with electrical connections without sacrificing current carrying capacity by benefiting from lower power losses than conventional designs. Low-voltage power circuit breakers, air circuit breakers, and the like are specifically designed with a withdrawable configuration. This type of configuration requires electrical connections that can be easily connected and disconnected to hold these types of circuit breakers, for example, on a workbench. The electrical connection between the circuit breaker body and the withdrawable bracket adds additional resistance to the current path; advantageously, this disclosure relates to a low-resistance electrical connection that maintains a robust mechanical connection.

[0008] In one aspect, an electrical connection system electrically connects a circuit breaker to a conductive bus. The electrical connection system includes a first conductive connector and a second conductive connector. The first connector has a base configured to attach to the bus and at least one tab protruding from the base. The second connector is configured to attach to the circuit breaker and electrically connect the circuit breaker to the bus via the first connector. The second connector includes a main body configured to attach to the circuit breaker, a first rib and a second rib protruding from the main body, and a first conductive spring and a second conductive spring. The ribs define slots therebetween, and each rib has its opposing surface facing the slot. The slot-facing surface of the first rib has a first channel formed therein, and the slot-facing surface of the second rib has a second channel formed therein. The first spring is positioned within the first channel, and the second spring is positioned within the second channel. The slot is configured to receive a tab of the first connector such that when the tab is received within the slot, the spring is biased against the tab.

[0009] On the other hand, the switchgear assembly electrically connects a circuit breaker to a conductive power bus. The switchgear assembly includes a housing configured to receive a circuit breaker, a power connector, and a circuit breaker connector therein. The power connector includes a prong projecting from a base mounted to the rear of the housing and configured for electrical connection to the bus. The circuit breaker connector is configured for electrical connection to the circuit breaker and for electrically connecting the circuit breaker to the bus via the power connector. The circuit breaker connector includes a main body configured to attach to the circuit breaker, a first rib and a second rib projecting from the main body, and a first conductive spring and a second conductive spring. The ribs define slots therebetween, and each rib has its opposing slot-facing surface. The slot-facing surface of the first rib has a first channel formed therein, and the slot-facing surface of the second rib has a second channel formed therein. The first spring is positioned within the first channel, and the second spring is positioned within the second channel. The slot is configured to receive the prong of the power connector such that when the prong is received within the slot, the spring is biased against the prong.

[0010] On another front, a circuit breaker connector connects a circuit breaker to a conductive power bus in an electrical assembly. The electrical assembly has a power connector including a prong projecting from a base, the prong configured for electrical connection to the bus. The circuit breaker connector includes a main body configured to attach to the circuit breaker, parallel first and second ribs projecting from the main body, and a first and second conductive spring. The ribs define slots therebetween, and each rib has its opposing slot-facing surface. The slot-facing surface of the first rib has a first channel formed therein, and the slot-facing surface of the second rib has a second channel formed therein. The first spring is positioned within the first channel, and the second spring is positioned within the second channel. The slot is configured to receive the prong of the power connector such that when the prong is received within the slot, the spring is biased against the prong, and the circuit breaker connector electrically connects the circuit breaker to the bus via the power connector.

[0011] Other objects and features of the invention will be apparent in part and set forth herein in part. Attached Figure Description

[0012] Figure 1 This is a partial perspective view of a representative circuit breaker assembly with electrical connections to a representative withdrawable bracket according to one embodiment.

[0013] Figure 2 According to one embodiment Figure 1 A perspective view of an exemplary circuit breaker connector for a circuit breaker assembly.

[0014] Figure 3A An example of a method for use with Figure 2 Inclined coils used in conjunction with circuit breaker connectors.

[0015] Figure 3B According to one embodiment Figure 3A An enlarged view of a single coil of a tilted coil.

[0016] Figure 4 and Figure 5 A circuit breaker connector is shown that is electrically and mechanically connected to a power connector according to one embodiment.

[0017] Throughout the accompanying drawings, corresponding reference numerals denote corresponding parts. Detailed Implementation

[0018] The features and other details of the concepts, systems, and techniques sought to be protected herein will now be described in more detail. It should be understood that any specific embodiments described herein are shown by way of illustration and are not intended to limit this disclosure and the concepts described herein. Features of the subject matter described herein may be employed in various embodiments without departing from the scope of the sought-protected concepts.

[0019] This disclosure provides a specific combination of multiple tilting coil electrical springs and coil supports that reduces the number of electrical joints used as the main current path power connection in a circuit breaker.

[0020] Figure 1 This is a perspective view of a representative circuit breaker assembly, generally represented as 100. Circuit breaker 100 can take various forms, but in at least some embodiments, circuit breaker 100 is preferably a "dischargeable" circuit breaker. In this respect, circuit breaker 100 can be conventionally mounted in a withdrawable bracket for moving in and out of the representative switchgear assembly. Figure 1 Generally designated 102, it is used for connection to a conductive power bus. The switchgear assembly 102 includes, for example, a cabinet (also referred to herein as a enclosure or housing) (not shown) and provides an electrical connection to the power bus (not shown).

[0021] In the illustrated embodiment, the circuit breaker 100 is electrically connected to the switchgear assembly 102 via one or more conductive power connectors 104, which may be rotatable joint mount (TJM) type connectors. Although Figure 1Only one power connector 104 is shown, but it should be readily understood that the switchgear assembly 102 will typically include multiple similarly oriented power connectors 104 (e.g., each of a plurality of circuit breaker connectors 108 corresponds to one connector). When properly connected, the circuit breaker 100 is operable to distribute power from a mains power source (e.g., a standard utility power supply) to a load. The circuit breaker 100 includes a housing 110, for example, having a rearward wall 112. The three substantially identical circuit breaker connectors 108 in the illustrated embodiment are attached to the rearward wall 112 of the circuit breaker housing 110 and oriented parallel to each other in a generally vertical direction.

[0022] Advantageously, the circuit breaker connector 108 according to one or more embodiments eliminates the need for conventional cluster supports fixed to the rear wall 112 and corresponding cluster connectors mounted on the supports for engaging the power connector 104.

[0023] Although Figure 1 An embodiment of the switching device is shown; however, it should be understood that aspects of this disclosure can be embodied in other types of electrical installations and other types of electrical connections. Furthermore, it should be understood that the drawings are not necessarily drawn to scale and are provided purely for illustrative purposes. For this reason, the individual and relative dimensions and orientations presented herein are not to be considered limiting. For this purpose, the circuit breaker 100 may include more or fewer than three circuit breaker connectors 108 having a similar or different structure from those shown in the drawings.

[0024] Each power connector 104 includes three main parts: a fork-shaped head 116, a base 118, and a yoke 120. Typically, the yoke 120 extends between the base 118 and the fork-shaped head 116 and electrically connects the base 118 to the fork-shaped head 116. The head 116, base 118, and yoke 120 can be integrally formed as a single-piece structure, such as... Figure 1 As shown. The fork-shaped head 116 is configured to electrically connect the power connector 104 to the circuit breaker connector 108. Figure 1 The circuit breaker 100. For example, the fork-shaped head 116 includes two generally flat, blunt-ended tabs (also referred to as fork teeth or plugs) 122 connected via a central web 124. Each tab 122 is designed to receive thereon and thus operably connect to one or more circuit breaker connectors, such as... Figure 1 The circuit breaker connector 108. Generally, the base 118 is configured to mount the power connector 104 to the mounting surface of the switchgear assembly 102 and operatively connect the power connector 104 to the circuit via a busbar. In one embodiment, this connection to the busbar is via, for example, a rotatable joint.

[0025] The power connector 104 can be adopted individually and in any combination in a variety of different configurations, including many shapes and sizes, some of which are disclosed in commonly assigned U.S. Patent No. 8,730,652, which is incorporated herein by reference in its entirety and for all purposes. In some aspects of this disclosure, the power connector 104 and / or the circuit breaker connector 108 may preferably be formed by casting or molding. Alternatively, the power connector 104 and / or the circuit breaker connector 108 may be formed by extrusion or other known methods, which may include a variety of known machining operations. For some applications, the power connector 104 and the circuit breaker connector 108 are preferably made of highly conductive materials such as copper or aluminum.

[0026] Figure 2 A circuit breaker connector 108 according to one or more embodiments is shown. As previously described, the circuit breaker connector 108 is designed to connect devices such as… Figure 1 The electrical switch of the circuit breaker 100 is electrically connected to, for example, Figure 1 The electrical conductors of the electrical busbar of the switchgear assembly 102. The circuit breaker 100 is electrically connected to each power connector 104 via circuit breaker connectors 108, three of which are in... Figure 1 As shown in the image. Now refer to... Figure 2 For example, each circuit breaker connector 108 has in Figure 2 The general term for the first ("circuit breaker side" or "proximal end") section or main body of 202 is related to the... Figure 2 The second (“busbar side” or “remote end”) portion, generally designated 204, is the opposite. The first portion 202 has a base 206 and is designed to be operably attached to the circuit breaker 108 at wall 112 via the base 206. In contrast, the second portion 204 is designed to be operably attached to one of the power connectors 104 (e.g., interference fit and clamping onto the tab 122). In one embodiment, each circuit breaker connector 108 includes a plurality of ribs 208 at the second end 204. Each pair of ribs 208 defines a slot 210, which is sized and shaped to receive the tab 122 of the power connector 104. When the circuit breaker 100 is mounted into a pull-out bracket of its associated switchgear assembly 102, the tab 122 of the power connector 104 is inserted into the corresponding slot 210. In this way, the circuit breaker 100 is electrically connected to the switchgear assembly 102.

[0027] To ensure a low-resistance electrical connection with the power connector 104, each rib 208 of the circuit breaker connector 108 has at least one channel or groove 212 formed in the inner surface facing the slot. When the circuit breaker connector 108 engages the power connector 104, the low-resistance connection embodying aspects of this disclosure is connected to the insert 122 using one or more electrical springs or tilting coils 214. The tilting springs 214 are configured to be biased (e.g., tilted) when the insert 122 is inserted into the slot 210, and thus the circuit breaker connector 108 accommodates a large range of misalignment. Pivot joints known in the art are no longer required. In one embodiment, a plurality of linear springs 214 may be configured such that more contact points can be formed between the circuit breaker connector 108 and the insert 122. In one embodiment, the slot 210 is slightly wider than the insert 122 when the spring 214 is not positioned in the channel 212, and slightly narrower than the insert 122 when the spring 214 is positioned in the channel 212. Inserting the insert 122 into the slot 210 (or mounting the slot 210 onto the insert 122) causes the opposing spring 214 to engage the side of the insert 122 and apply force thereto. The spring 214 also applies force to the interior of the channel 212, resulting in an interference fit between the power connector 104 and the circuit breaker connector 108.

[0028] Typically, the conductive spring 214 functions as an electrical conduit for carrying current between the switchgear assembly 102 and the circuit breaker 100. Although not essential in nature, the spring 214 and the circuit breaker connector 108 are structurally identical. The base 206 of the circuit breaker connector 108 is configured to be rigidly mounted or otherwise electrically connected to the circuit breaker 100 at the rear wall 112 via, for example, one or more bolt cavities through which bolts or other fasteners may pass. When properly positioned on the corresponding circuit breaker connector 108 and mating with the corresponding power connector 104, the conductive spring 214 functions as an electrical conduit for carrying current between the switchgear assembly 102 and the circuit breaker 100.

[0029] Figure 3A and Figure 3B Further aspects of a representative tilting spring 214 embodying various aspects of this disclosure are shown. The spring 214 applies a nearly constant force over its operating deflection range, and its force remains consistent even under extreme temperature variations. According to one or more embodiments, the preferably tilting spring 214 resists compressive deformation, and its individual coils 302 compensate for misalignment, tolerance variations, and irregularities in mating surfaces. Figure 3BAs shown, the coil 302 of the spring 214 can be elliptical instead of circular. Adjusting the size of the spring groove 212, the size and degree of the slope or angle of the spring 214, the size and shape of the individual coils 302, the wire diameter, and other characteristics allows for precise control of the force required for latching, locking, holding, engaging, and disengaging, for applications requiring electrical conduction and mechanical connections.

[0030] Figure 4 and Figure 5 A circuit breaker connector 108 is shown, electrically and mechanically connected to a power connector 104 according to an embodiment. When connected in this manner, the circuit breaker 100 can be considered part of the switchgear assembly 102. By design, the circuit breaker connector 108 and the power connector 104 form only a single sliding joint. This combination of reducing the number of electrical joints from two to one and increasing the total number of contact points allows the joint to have relatively low resistance.

[0031] The features of the circuit breaker connector 108 embodying aspects of this disclosure advantageously reduce the resistance of the electrical connection formed between the circuit breaker connector 108 and the power connector 104, and consequently reduce the total power loss of the circuit breaker 100. Reduced power loss supports sustainability and reduces the carbon footprint of power distribution equipment and systems. Furthermore, the internal contact resistance of conventional circuit breaker assemblies can generate significant heating within the circuit breaker, particularly under high current-carrying conditions. Additionally, conventional circuit breaker assemblies advantageously have a relatively small contact area, preventing efficient heat dissipation from the circuit breaker, where heat can be handled by other mechanisms (e.g., natural convection radiators). The features of the circuit breaker connector 108 embodying aspects of this disclosure advantageously provide a larger contact area relative to conventional connectors, allowing more heat to be conducted away from the circuit breaker 100. This lowers the internal temperature of the circuit breaker 100 and allows the heat dissipating therefrom to be handled by other components outside the circuit breaker 100 (e.g., circuit breaker terminals or equipment conductors).

[0032] It should be noted that the roles of the circuit breaker connector 108 and the power connector 104 can be reversed without departing from the scope of the invention. In other words, the connector in the form of circuit breaker connector 108 can provide an electrical connection to the busbar of switchgear assembly 102, and the connector in the form of power connector 104 can provide an electrical connection to circuit breaker assembly 100. It should also be noted that aspects of this disclosure can be applied to other circuit breaker designs (e.g., externally mounted circuit breakers) and other electrical connections (e.g., I-Line claws in a switchboard) without departing from the scope of the invention.

[0033] Unless otherwise stated, the order of execution or performance of the operations according to various aspects of this disclosure shown and described herein is not essential. That is, unless otherwise stated, operations may be performed in any order, and embodiments may include more or fewer operations than those disclosed herein. For example, it is conceivable that a particular operation may be performed or implemented before, simultaneously with, or after another operation within the scope of this invention.

[0034] When describing elements of the invention or embodiments thereof, the articles “a,” “an,” “the,” and “said” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to those listed.

[0035] Not all components depicted in the illustrations or descriptions are essential. Furthermore, some implementations and embodiments may include additional components. Variations in the arrangement and type of components may be made without departing from the spirit or scope of the claims set forth herein. Additional, different, or fewer components may be provided, and components may be combined. Alternatively or additionally, a component may be implemented by several components.

[0036] The above description illustrates embodiments by way of example and not limitation. This description enables those skilled in the art to make and use aspects of the invention, and describes numerous embodiments, adaptations, variations, alternatives, and uses of aspects of the invention, including modes currently considered best for carrying out aspects of the invention. Furthermore, it should be understood that aspects of the invention are not limited in their application to the details of the construction and arrangement of components set forth in the following description or shown in the accompanying drawings. Aspects of the invention can have other embodiments and can be practiced or performed in various ways. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting.

[0037] It is obvious that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. Since various changes can be made to the above-described constructions and methods without departing from the scope of the invention, all content included in the above description and shown in the drawings is intended to be illustrative rather than restrictive.

[0038] In view of the foregoing, it will be seen that several advantages of realizing various aspects of the present invention have been achieved and other advantageous results have been obtained.

[0039] The abstract and summary are provided to help the reader quickly determine the nature of this technical disclosure. They are submitted with the understanding that they will not be used to interpret or limit the scope or meaning of the claims. The summary is provided to introduce some concepts in a simplified form, which will be further described in the detailed embodiments. The summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help identify the claimed subject matter.

Claims

1. A power connection system for electrically connecting a circuit breaker to a conductive busbar, the power connection system comprising: A first conductive connector has a base configured to be attached to a busbar and at least one insert protruding from the base; and A second conductive connector, configured to be attached to a circuit breaker and electrically connected to the busbar via the first conductive connector, the second conductive connector comprising: The backbone is configured to be attached to the circuit breaker; A first rib and a second rib, protruding from the main trunk, define a slot between them and each has an opposing surface facing the slot, the opposing surface of the first rib having a first channel formed therein, and the opposing surface of the second rib having a second channel formed therein; and A first conductive spring and a second conductive spring, the first conductive spring being positioned within a first channel formed in the slot-facing surface of the first rib, and the second conductive spring being positioned within a second channel formed in the opposite slot-facing surface of the second rib. The slot is configured to receive the tab of the first conductive connector such that when the tab is received in the slot, the first conductive spring and the second conductive spring are biased against the tab.

2. The power connection system according to claim 1, wherein, The slot has a first width, and the insert has a second width less than the first width, such that when the insert is received in the slot, the insert can move within the slot.

3. The power connection system according to claim 2, wherein, When the conductive spring is not biased against the insert, the spacing between the conductive springs is less than the second width.

4. The power connection system according to claim 1, wherein, The first rib and the second rib are parallel to each other.

5. The power connection system according to claim 1, wherein, The conductive spring is tilted.

6. The power connection system according to claim 1, wherein, The conductive spring includes multiple coils, each of which has an elliptical shape.

7. The power connection system according to claim 1, wherein, The main trunk and the first and second ribs of the second conductive connector are formed as a single-piece integral structure.

8. The power connection system according to claim 1, wherein, The base and the insert of the first conductive connector are formed as a single-piece integral structure.

9. A switchgear assembly for electrically connecting a circuit breaker to a conductive power bus, the switchgear assembly comprising: A housing configured to receive the circuit breaker therein; A power connector including a protruding tab from a base, the base of the power connector being mounted to the rear of the housing and configured for electrical connection to the busbar; A circuit breaker connector configured to be electrically connected to the circuit breaker and to connect the circuit breaker to the busbar via the power connector, the circuit breaker connector comprising: The main trunk, which is configured to be attached to the circuit breaker; A first rib and a second rib, protruding from the main trunk, define a slot between them and each has an opposing surface facing the slot, the opposing surface of the first rib having a first channel formed therein, and the opposing surface of the second rib having a second channel formed therein; and A first conductive spring and a second conductive spring, the first conductive spring being positioned within a first channel formed in the slot-facing surface of the first rib, and the second conductive spring being positioned within a second channel formed in the opposite slot-facing surface of the second rib. The slot is configured to receive the tab of the power connector such that when the tab is received in the slot, the first conductive spring and the second conductive spring are biased against the tab.

10. The switchgear assembly according to claim 9, wherein, The slot has a first width, and the insert has a second width less than the first width, such that when the insert is received in the slot, the insert can move within the slot.

11. The switchgear assembly of claim 10, wherein, When the conductive spring is not biased against the insert, the spacing between the conductive springs is less than the second width.

12. The switchgear assembly according to claim 9, wherein, The first rib and the second rib are parallel to each other.

13. The switchgear assembly according to claim 9, wherein, The conductive spring is tilted.

14. The switchgear assembly according to claim 9, wherein, The conductive spring includes multiple coils, each of which has an elliptical shape.

15. The switchgear assembly according to claim 9, wherein, The main trunk and the first and second ribs of the circuit breaker connector are formed as a single-piece integral structure.

16. The switchgear assembly according to claim 9, wherein, The base and the insert of the power connector are formed as a single-piece integral structure.

17. A circuit breaker connector for connecting a circuit breaker to a conductive power bus in an electrical assembly, the electrical assembly having a power connector including a protruding tab from a base, the base of the power connector being configured for electrical connection to the bus, the circuit breaker connector comprising: The main trunk is configured to be attached to the circuit breaker; Parallel first and second ribs protrude from the main trunk, defining a slot between them and each having its opposing slot-facing surface, the slot-facing surface of the first rib having a first channel formed therein, and the opposing slot-facing surface of the second rib having a second channel formed therein. and A first conductive spring and a second conductive spring, the first conductive spring being positioned within a first channel formed in the slot-facing surface of the first rib, and the second conductive spring being positioned within a second channel formed in the opposite slot-facing surface of the second rib. The slot is configured to receive the tab of the power connector such that when the tab is received in the slot and the circuit breaker connector electrically connects the circuit breaker to the bus via the power connector, the first conductive spring and the second conductive spring are biased against the tab.

18. The circuit breaker connector according to claim 17, wherein, The slot has a first width, and the insert has a second width less than the first width, such that when the insert is received in the slot, the insert can move within the slot.

19. The circuit breaker connector according to claim 18, wherein, When the conductive spring is not biased against the insert, the spacing between the conductive springs is less than the second width.

20. The circuit breaker connector according to claim 17, wherein, Each of the conductive springs is inclined and includes multiple coils, each coil having an elliptical shape.

21. The circuit breaker connector according to claim 17, wherein, The main body of the circuit breaker connector, as well as the first rib and the second rib, are formed as a single-piece integral structure.

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