Technicalfield
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The present invention relates to medium-voltage gas circuit breakers, and more precisely to an electric shunt and method for transitioning an electric contact between a fixed contact to an auxiliary contact of an electric shunt.
Background of the disclosure
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In conventional circuit breaker solutions, a contact knife is employed to switch the electric circuit between a fixed contact and an auxiliary contact of an electric shunt by physically moving between these contacts. However, these solutions present a technical contradiction. The auxiliary contact must be positioned at a sufficient distance from the fixed contact to prevent the initiation of an electric arc between them during static conditions. Conversely, during the transition of the contact knife from the auxiliary contact to the fixed contact, the auxiliary contact must be positioned in close proximity to the fixed contact to prevent arcing during the switching process. This contradiction complicates the design and reliable operation of such circuit breakers. The present invention seeks to resolve this contradiction by providing an improved solution.
Summary of the disclosure
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It is a goal of this invention to provide construction of electric shunt which will reduce the risk of arc ignition between a fix contact and an auxiliary contact.
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According to an aspect of the present invention there is provided an electric shunt comprising:
- a shunt body,
- a fixed contact,
- an auxiliary contact,
- a returning means,
- wherein the fixed contact is mounted on the shunt body, and the auxiliary contact is movably coupled with the shunt body such that the auxiliary contact is able to move slidably in a guideway of the shunt body between a first position and a second position, wherein in the first position distance between the auxiliary contact and the fixed contact is the smallest, and in the second position the distance between the auxiliary contact and the fixed contact is the greatest, and the returning means are coupled with the shunt body and the auxiliary contact such that the returning means are biasing the auxiliary contact toward the first position.
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Preferably the auxiliary contact comprises an detachable electrical contact.
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Preferably the auxiliary contact comprises a slider located movably in the guideway.
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Preferably the guideway is curved, preferable the guideway forms a part of a circle.
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In one embodiment the returning means are in form of a spring and a gear, wherein the auxiliary contact comprises an sprocket which is coupled with the gear, wherein the gear is connected to the shunt body such that the gear is able to rotate, and the spring is configured to induce the return motion of the gear during the rotation.
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Preferable the spring is in form of flat spring connected to the shunt body and the gear.
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In one of the preferred embodiments the auxiliary contact and the guideway are forming a chamber in which the returning means are placed which are configure to act against the guideway and the auxiliary contact.
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Preferable the returning means are in form of a compression spring.
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In another one of the preferred embodiments the returning means comprise a spring container with a piston rod and a returning spring, wherein the returning means are attached to the shunt body and the auxiliary contact, such that the spring container is connected to the shunt body or the auxiliary contact and the piston rod is connected to the auxiliary contact or shunt body respectively.
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Preferably the spring container and/or the piston rod is pivotally attached to the shunt body and/or the auxiliary contact.
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In a second aspect of the disclosure, there is provided a method of transitioning an electric contact between a fixed contact to an auxiliary contact of an electric shunt designed in accordance with the disclosure, comprising steps of:
- a) transitioning at least one knife between the fixed contact and the auxiliary contact,
- b) moving, by the at least one knife, the auxiliary contact from a first position to a second position,
- c) releasing the auxiliary contact when the at least one knife moves further than the second position and the at least one knife is no longer in contact with the auxiliary contact,
- d) returning, by a returning means, the auxiliary contact toward the first position.
Advantages of the disclosure
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The present invention addresses the challenge associated with ensuring continuous engagement of the moving contacts with the sliding interface of the circuit for as long as possible. In conventional designs, when the moving contact switches to the auxiliary contact, the sliding interface must be positioned at a significant distance from the auxiliary contact to prevent arcing.
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The invention proposes a novel approach by incorporating a movable auxiliary contact. This auxiliary contact is actuated by the contact knife during the transition phase, allowing it to be positioned away from the fixed contact at that stage. When the contact knife is not engaged with the auxiliary contact, a spring mechanism moves the auxiliary contact close to the fixed contact, maintaining a safe distance to prevent arcing.
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This inventive solution effectively resolves the issue of managing the distance between the auxiliary contact and the fixed contact, thereby significantly reducing the risk of arc ignition and improving overall circuit breaker reliability.
Brief description of the drawings
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The present disclosure will be discussed with reference to drawings, where:
- Fig. 1 - depicts an electric shunt known from the prior art.
- Fig. 2 - depicts an electric shunt known from the prior art.
- Fig. 3-depicts an electric shunt in first position, wherein a returning means are in form of a spring and a gear.
- Fig. 4 - depicts an electric shunt in second position, wherein a returning means are in form of a spring and a gear.
- Fig. 5- depicts an auxiliary contact, wherein a returning means are in form of a spring and a gear.
- Fig. 6 - depicts an electric shunt in first position, wherein an auxiliary contact and a guideway are forming a chamber containing a returning means.
- Fig. 7 - depicts an electric shunt in second position, wherein an auxiliary contact and a guideway are forming a chamber containing a returning means.
- Fig. 8 - depicts an auxiliary contact, wherein an auxiliary contact and a guideway are forming a chamber containing a returning means.
- Fig. 9 - depicts an electric shunt in first position, wherein a returning means comprise a spring container with a piston rod and a returning spring.
- Fig. 10 - depicts an electric shunt in second position, wherein a returning means comprise a spring container with a piston rod and a returning spring.
- Fig. 11 - depicts an auxiliary contact, wherein a returning means comprise a spring container with a piston rod and a returning spring.
- Fig. 12 - depicts an auxiliary contact in cross-sectional view, wherein a returning means comprise a spring container with a piston rod and a returning spring.
- Fig. 13 - depicts a four sequences of a method of transitioning an electric contact between a fixed contact to an auxiliary contact of an electric shunt
Detailed description of the disclosure
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It is noted that in the description of the figures, same reference numerals refer to the same of similar components performing a same of essentially similar function.
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For a proper understanding of the disclosure, in the detailed description below, corresponding elements or parts of different embodiments will be denoted with identical reference numerals in the drawings. It is noted that the drawings only illustrate typical examples and are therefore not to be considered to limit the scope of the subject matter of the claims. The drawings are incorporated for facilitating an understanding of the disclosure and are thus not necessarily drawn to scale. Advantages of the subject matter as claimed will become apparent to those skilled in the art upon reading the description in conjunction with the accompanying drawings.
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Fig. 1 and fig. 2 depict an electric shunt known from the prior art, wherein the fixed contact 2 and the auxiliary contact 3 are fixed on the shunt body 1. Distance between the auxiliary contact 3 and the fixed contact 2 does not change during shunt operation.
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Part 9 is an accessory of the shunt, which is not involved in transitioning electric contacts of shunt.
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The present invention discloses an electric shunt comprising: a shunt body 1, a fixed contact 2, an auxiliary contact 3, a returning means 4, wherein the fixed contact 2 is mounted on the shunt body 1 , and the auxiliary contact 3 is movably coupled with the shunt body 1 such that the auxiliary contact 3 is able to move slidably in a guideway 6 of the shunt body 1 between a first position A and a second position B, wherein in the first position A a distance between the auxiliary contact 3 and the fixed contact 2 is the smallest, and in the second position B the distance between the auxiliary contact 3 and the fixed contact 2 is the greatest. The returning means 4 are coupled with the shunt body 1 and the auxiliary contact 3 such that the returning means 4 are biasing the auxiliary contact 3 toward the first position A.
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The following examples describe embodiments of the auxiliary contact 3 comprises an detachable electrical contact 3.1 and a slider 3.2 that is movably positioned within the guideway 6. In this embodiments, the guideway 6 is curved and specifically forms a segment of a circular path. However, these features are not obligatory and may be substituted with alternative configurations. For instance, the detachable nature of the electrical contact 3.1 and the slider 3.2 are formed as a single, integral element. Such modifications fall within the scope of the invention and do not depart from its essential principles.
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Fig. 3, fig. 4 and fig. 5 depicts an example of electric shunt wherein the returning means are in form of a spring 4.1 and a gear 4.2, and the auxiliary contact 3 comprises an sprocket 3.3 which is coupled with the gear 4.2, and the gear 4.2 is connected to the shunt body 1 such that the gear 4.2 is able to rotate, and the spring 4.1 is configured to induce the return motion of the gear 4.2 during the rotation. The spring 4.1 is in form of flat spring connected to the shunt body 1 and the gear 4.2.
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Fig. 3 illustrates the electric shunt in first position A, wherein the returning means 4 are in a mounted position - distance between the auxiliary contact and the fixed contact is the smallest. In this configuration (shown in detail in fig. 5), the gear4.2 is prevented by shape connections from father movement by the flat spring 4.1, indicating that the gear has reached its limit of travel. The flat spring 4.1 is in preload state. This preloaded condition ensures that the returning means 4 are positioned to function optimally during the transition of the electric shunt, facilitating reliable operation of the mechanism.
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Fig. 4 illustrates the electric shunt in second position B, wherein the spring 4.1 is in the state of maximum tension as anticipated for the operational process - distance between the auxiliary contact and the fixed contact is the biggest. The gear 4.2 increases the tension of the flat spring 4.1 as it rotates, simultaneously moving the slider 3.2, which holds the electric contact 3.1, in to the second position B. This movement ensures that the auxiliary contact 3.1 is appropriately displaced from the fixed contact during this phase, optimizing the system for its intended function and reducing the potential for arc formation.
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Fig. 6, fig. 7 and fig. 8 depict an example of electric shunt wherein the auxiliary contact 3 and the guideway 6 are forming a chamber 7 in which the returning means 4 in form of a compression spring 4.3 are placed which are configure to act against the guideway 6 and the auxiliary contact 3.
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Fig. 6 depicts the electric shunt in first position A, wherein the compression spring4.3 is in preload state. The geometric design of the slider 3.2 determines the maximum displacement of the slider 3.2 in the guideway 6 and the maximum space for the compression spring 4.3. This preloaded condition ensures that the returning means 4 are positioned to function optimally during the transition of the electric shunt, facilitating reliable operation of the mechanism.
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Fig. 9, fig. 10, fig. 11 and fig. 12 depict an example of electric shunt similar to described above. The returning means 4 comprise a spring container 4.4 with a piston rod 4.5 and a returning spring 4.6, wherein the returning means 4 are attached to the shunt body 1 and the auxiliary contact 3, such that the spring container 4.4 is connected to the shunt body 1 or the auxiliary contact 3 and the piston rod 4.5 is connected to the auxiliary contact 3 or shunt body 1 respectively. The spring container 4.4 and the piston rod 4.5 is pivotally attached to the shunt body 1 and the auxiliary contact 3. The length of piston rod 4.5 determines the maximum displacement of the slider 3.2 in the guideway 6.
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Fig. 13 depicts a four sequences of a method of transitioning an electric contact between a fixed contact to an auxiliary contact of an electric shunt comprising a steps of:
- a) transitioning two knives 8 between the fixed contact 2 and the auxiliary contact 3,
- b) moving, by the knives 8, the auxiliary contact 3 from a first position A to a second position B,
- c) releasing the auxiliary contact 3 when the knives 8 moves back to the second position B and the knives 8 are no longer in contact with the auxiliary contact 3,
- d) returning, by a returning means 4, the auxiliary contact 3 toward the first position A.
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In the first sequence (see fig. 13 a)), two knives 8 move in unison with the auxiliary contact 3 towards the fixed contact 2. The auxiliary contact 3 moving from position B to A is moved by the returning means 4 an held by the knives 8. This coordinated backward and forward movement allows a rapid transitioning of electric contact, without ignite arc when the knives 8 are in contact with the auxiliary contact 3.
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In the second sequence (see fig. 13 b)), the auxiliary contact 3 reaches position A.
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In the third sequence (see fig. 13 c)), the knives 8 disengage from the auxiliary contact 3 by moving beyond its range of mobility.
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In the final sequence (see fig. 13 d)), the knives 8 slide over the surface of the fixed contact 2, establishing the necessary electrical connection. This sequence of operations is designed to ensure smooth and efficient transition, minimizing the risk of arcing and ensuring reliable electrical contact.
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The ensuing description above provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the disclosure, it being understood that various changes may be made in the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the disclosure.