Circuit breaker

Abstract

The present invention relates to a circuit breaker, comprising: - a switching element (2); - a first terminal (1); - a second terminal (1); - a heatsink (7); and - an airduct (8); wherein the switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other, wherein the two contacts are a fixed contact and a moveable contact, and wherein when the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts; wherein the heatsink is connected to a first part of the circuit breaker; wherein a first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct; and wherein at least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a circuit breaker, for a switchgear, such as a low voltage or medium voltage circuit switchgear.BACKGROUND OF THE INVENTION

[0002] Switchgear, such as Gas Insulated Switchgear (GIS), generally have several compartments, such as a circuit breaker compartment, cable connection compartment, one or more busbar compartments, and other component compartments.

[0003] Heat is generated in these compartments due to joule heating as current flows through conductors, and this heat must be extracted.

[0004] The main circuit of a medium voltage circuit breaker contains sections of high temperature due to power losses of the nominal current. In high current applications, heatsinks are used to dissipate the power losses to the environment.

[0005] Heatsinks are cooled as air flows into them, is heated, and flows out thereby extracting heat from the heatsink and cooling the part of the circuit breaker to which the heatsink is thermally connected.

[0006] A certain amount of air is required to interact with a heatsink in order to provide the required cooling by transporting heat away from the heatsink, and this results in a total surface area of vanes of a heatsink being very large and leads to very large heatsinks.

[0007] The resulting very large heatsinks, and the overall increased sizes of systems, is frequiently not desirable.

[0008] There is a need to improve this situation.SUMMARY OF THE INVENTION

[0009] Therefore, it would be advantageous to provide an improved way of cooling a circuit breaker of a switchgear.

[0010] The object of the present invention is solved with the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.

[0011] There is provided a circuit breaker, comprising: a switching element; a first terminal; a second terminal; a heatsink; and an airduct.

[0012] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts.

[0013] The heatsink is connected to a first part of the circuit breaker.

[0014] A first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct.

[0015] At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0016] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and enters the airduct. The air rises in the airduct, and this draws cold air into the heatsink at a faster rate than if the hot air from the heatsink did not enter the airduct. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0017] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0018] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and then they developed the airduct technique to increase the airflow through the heatsink.

[0019] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0020] In an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0021] In an example, the circuit breaker comprises an insulating pole housing, and the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0022] In an example, the circuit breaker comprises a second heatsink. The second heatsink is connected to a second part of the circuit breaker. A second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the airduct can enter the second heatsink.

[0023] In this was the air rising through the airduct can cool the upper heatsink. Also, hot air exits the top of the upper heatsink and this in effect draws air out of the airduct such that the airflow through the airduct is further increased and both the lower heatsink and upper heatsink are more effectively cooled, leading to further improvement in the cooling of the circuit breaker.

[0024] At first sight this appears counterintuitive, because the upper heatsink is now being fed with the hot air that exits the lower heatsink. However, the inventors realised that the increase in velocity of the heated air that now passes through the upper heatsink improves the cooling of the upper heatsink over and above the situation when the airduct is not used, and the lower heatsink is also now further improved in its cooling as the air velocity has been further increased due to there now being a heatsink at both the top and bottom of the airduct.

[0025] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0026] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0027] In an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0028] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0029] In an example, the heatsink comprises aluminium and / or copper.

[0030] In an example, the second heatsink comprises aluminium and / or copper.

[0031] In an example, the heatsink comprises a plurality of fins or vanes.

[0032] In an example, the second heatsink comprises a plurality of fins or vanes.

[0033] There is provided a circuit breaker, comprising: a switching element; a first terminal; a second terminal; a heatsink; and an airduct.

[0034] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts.

[0035] The heatsink is connected to a first part of the circuit breaker.

[0036] A first open end of the airduct is connected to the heatsink, such that air exiting the airduct can enter the heatsink.

[0037] At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0038] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and rises. This then draws air into the airduct and there is a chimney effect, where air entering the heatsink is increased over that if the airduct was not present. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0039] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0040] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and thus they developed the airduct technique to increase the airflow through the heatsink.

[0041] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0042] In an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0043] In an example, the circuit breaker comprises an insulating pole housing, and the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0044] In an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0045] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0046] In an example, the circuit breaker comprises a second heatsink (6), wherein the heatsink is connected to a second part of the circuit breaker, wherein a second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the second heatsink can enter the airduct.

[0047] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0048] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0049] In an example, the heatsink comprises aluminium and / or copper.

[0050] In an example, the second heatsink comprises aluminium and / or copper.

[0051] In an example, the heatsink comprises a plurality of fins or vanes.

[0052] In an example, the second heatsink comprises a plurality of fins or vanes.BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Exemplary embodiments will be described in the following with reference to the following drawing: Fig. 1 shows an example of a circuit breaker without an airduct; and Fig. 2 shows an example of a circuit breaker with an airduct according to an embodiment of the invention. DETAILED DESCRIPTION OF EMBODIMENTS

[0054] Fig. 1 shows an example of a circuit breaker without an airduct

[0055] Fig. 2 shows an example of a circuit breaker with an airduct 8 according to an embodiment of the invention.

[0056] In Fig. 2 the airduct 8 is connected to both lower heatsink 7 and an upper heatsink 6. However, it could be connected to just the lower heatsink 7 or just connected to the upper heatsink 6.

[0057] It is also to be noted that in Fig. 2 the airduct 9 has an initial horizontal section leading from the lower heatsink 7 and then a vertical section and then another horizontal section leading into the upper heatsink 6. This is just for visualization, where to aid efficiency the airflow out of and into the heatsinks is parallel to vanes or fins of the heatsink.

[0058] However, the vanes or fins of either of both of the heatsinks could be oriented vertically and the one or other of the heatsinks could be offset. This means that the airduct 8 could be connected to the top of the lower heatsink 7 such that this end is vertically oriented and then be connected to the bottom of the upper heatsink 6 such that the airduct is oriented vertically along its length.

[0059] Or the airduct 8 could be connected to the side of the lower heatsink 7, have an initial horizontal section, then a vertical section and then be connected to the bottom of the upper heatsink 6.

[0060] Or the airduct 8 could be connected to the top of the lower heatsink 7, extend vertically and then be connected to the side of the upper heatsink 6 through a horizontal section.

[0061] The following relates to a number of different embodiments of the new development for cooling a circuit breaker.

[0062] According to an example, a circuit breaker, comprises: a switching element 2; a first terminal 1; a second terminal 1; a heatsink 7; and an airduct 8.

[0063] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts. The heatsink is connected to a first part of the circuit breaker. A first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct. At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0064] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and enters the airduct. The air rises in the airduct, and this draws cold air into the heatsink at a faster rate than if the hot air from the heatsink did not enter the airduct. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0065] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0066] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and then they developed the airduct technique to increase the airflow through the heatsink.

[0067] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0068] It is to be noted that when the two contacts have been brought together and are in contact with each other, the first terminal is again electrically connected to same terminal it was previously connected to and the second terminal is again electrically connected to the contact it was previously electrically connected to, but the two terminals are now also electrically connected to each other.

[0069] According to an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0070] According to an example, the circuit breaker comprises an insulating pole housing 4. The heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0071] According to an example, the circuit breaker comprises a second heatsink 6. The second heatsink is connected to a second part of the circuit breaker. A second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the airduct can enter the second heatsink.

[0072] In this was the air rising through the airduct can cool the upper heatsink. Also, hot air exits the top of the upper heatsink and this in effect draws air out of the airduct such that the airflow through the airduct is further increased and both the lower heatsink and upper heatsink are more effectively cooled, leading to further improvement in the cooling of the circuit breaker.

[0073] At first sight this appears counterintuitive, because the upper heatsink is now being fed with the hot air that exits the lower heatsink. However, the inventors realised that the increase in velocity of the heated air that now passes through the upper heatsink improves the cooling of the upper heatsink over and above the situation when the airduct is not used, and the lower heatsink is also now further improved in its cooling as the air velocity has been further increased due to there now being a heatsink at both the top and bottom of the airduct.

[0074] According to an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0075] According to an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0076] According to an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0077] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0078] According to an example, the heatsink comprises aluminium and / or copper.

[0079] According to an example, the second heatsink comprises aluminium and / or copper.

[0080] According to an example, the heatsink comprises a plurality of fins or vanes.

[0081] According to an example, the second heatsink comprises a plurality of fins or vanes.

[0082] In an example, a circuit breaker, comprises: a switching element 2; a first terminal 1; a second terminal 1; a heatsink 7; and an airduct 8.

[0083] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts. The heatsink is connected to a first part of the circuit breaker. A first open end of the airduct is connected to the heatsink, such that air exiting the airduct can enter the heatsink. At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0084] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and rises. This then draws air into the airduct and there is a chimney effect, where air entering the heatsink is increased over that if the airduct was not present. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0085] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0086] According to an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0087] According to an example, the circuit breaker comprises an insulating pole housing 4. The heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0088] According to an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0089] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0090] In an example, the circuit breaker comprises a second heatsink (6), wherein the heatsink is connected to a second part of the circuit breaker, wherein a second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the second heatsink can enter the airduct.

[0091] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0092] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0093] In an example, the heatsink comprises aluminium and / or copper.

[0094] In an example, the second heatsink comprises aluminium and / or copper.

[0095] In an example, the heatsink comprises a plurality of fins or vanes.

[0096] In an example, the second heatsink comprises a plurality of fins or vanes.

[0097] The new development is now described in further specific detail, where reference is again made to Fig. 1 and Fig. 2.

[0098] The comparison of Fig. 1 and Fig. 2 shows the difference between both airflow situations, where the airflow is represented by the arrows. Both heatsinks are fed with air from their environment, heat it and accelerate it upwards and depending on their geometry. The addition of an airduct forces the air from the lower heatsink to run straight upwards which gains the effect of getting more cold air from underneath. The fast pre-heated air feeds the upper heatsink, where its high velocity is still capable of cooling the upper heatsink (in contrast to slow hot air). This makes the whole cooling more controlled, and both heatsinks more efficient.

[0099] Thus, the inventors started from the position where heatsinks are used to expose a big surface area to the environment, the heat transport takes place, when a certain airflow runs towards and from the heatsink. This means that for a smaller heatsink that is required in some situations when for example there is a space limitation, there is not enough surface to create such heat transport. The inventors then sought to make sure that enough air is able to flow into the heatsink and exits it easily too. This led to the realization to take the geometrical environment of the heatsink into account, with respect to utilization of the airduct described here.

[0100] The inventor's work established that one important parameter of a heatsink's cooling capability is the velocity of airflow inside. Known from chimneys, the heating of the air accelerates its flow, when it is guided in narrow compartments instead of simply being expose to open volumes.

[0101] As shown in Fig. 1, two heatsinks are arranged vertically to each other. Both have to dissipate heat, which leads to the situation that the airflow occurs in an uncontrolled manner and even the cooling capability of the upper heatsink can be decreased by being exposed to heated air from the lower heatsink.

[0102] The development shown in Fig. 2, with respect to one detailed embodiment, is to connect both heatsinks with an airduct, that takes up the air from the lower heatsink and guides it into the upper heatsink.

[0103] The inventors established that even while the upper heatsink is fed with pre-heated air, the air-guiding creates such a high flow velocity that the upper heatsink is ventilated properly to transport its heat away.

[0104] Thus, the new development made by the inventor relates to a vertical airduct being used to increase airflow through a heatsink, and to increase airflow through two heatsinks with common airduct between vertically arranged heatsinks. The development came about from the understanding that airflow to and from the heatsinks is a vital parameter to transport heat, and where airducts are used to guide the airflow and take advantage from the accelerated heated air.Reference Numerals

[0105] 1.Terminals of Main Circuit 2.Switching Element 3.Drive Housing 4.Insulating Pole Housing 6.Upper Heatsink 7.Lower Heatsink 8.Airduct from lower to upper Heatsink

Examples

Embodiment Construction

[0054]Fig. 1 shows an example of a circuit breaker without an airduct

[0055]Fig. 2 shows an example of a circuit breaker with an airduct 8 according to an embodiment of the invention.

[0056]In Fig. 2 the airduct 8 is connected to both lower heatsink 7 and an upper heatsink 6. However, it could be connected to just the lower heatsink 7 or just connected to the upper heatsink 6.

[0057]It is also to be noted that in Fig. 2 the airduct 9 has an initial horizontal section leading from the lower heatsink 7 and then a vertical section and then another horizontal section leading into the upper heatsink 6. This is just for visualization, where to aid efficiency the airflow out of and into the heatsinks is parallel to vanes or fins of the heatsink.

[0058]However, the vanes or fins of either of both of the heatsinks could be oriented vertically and the one or other of the heatsinks could be offset. This means that the airduct 8 could be connected to the top of the lower heatsink 7 such that this e...

FIELD OF THE INVENTION

[0001] The present invention relates to a circuit breaker, for a switchgear, such as a low voltage or medium voltage circuit switchgear.BACKGROUND OF THE INVENTION

[0002] Switchgear, such as Gas Insulated Switchgear (GIS), generally have several compartments, such as a circuit breaker compartment, cable connection compartment, one or more busbar compartments, and other component compartments.

[0003] Heat is generated in these compartments due to joule heating as current flows through conductors, and this heat must be extracted.

[0004] The main circuit of a medium voltage circuit breaker contains sections of high temperature due to power losses of the nominal current. In high current applications, heatsinks are used to dissipate the power losses to the environment.

[0005] Heatsinks are cooled as air flows into them, is heated, and flows out thereby extracting heat from the heatsink and cooling the part of the circuit breaker to which the heatsink is thermally connected.

[0006] A certain amount of air is required to interact with a heatsink in order to provide the required cooling by transporting heat away from the heatsink, and this results in a total surface area of vanes of a heatsink being very large and leads to very large heatsinks.

[0007] The resulting very large heatsinks, and the overall increased sizes of systems, is frequiently not desirable.

[0008] There is a need to improve this situation.SUMMARY OF THE INVENTION

[0009] Therefore, it would be advantageous to provide an improved way of cooling a circuit breaker of a switchgear.

[0010] The object of the present invention is solved with the subject matter of the independent claims, wherein further embodiments are incorporated in the dependent claims.

[0011] There is provided a circuit breaker, comprising: a switching element; a first terminal; a second terminal; a heatsink; and an airduct.

[0012] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts.

[0013] The heatsink is connected to a first part of the circuit breaker.

[0014] A first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct.

[0015] At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0016] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and enters the airduct. The air rises in the airduct, and this draws cold air into the heatsink at a faster rate than if the hot air from the heatsink did not enter the airduct. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0017] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0018] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and then they developed the airduct technique to increase the airflow through the heatsink.

[0019] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0020] In an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0021] In an example, the circuit breaker comprises an insulating pole housing, and the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0022] In an example, the circuit breaker comprises a second heatsink. The second heatsink is connected to a second part of the circuit breaker. A second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the airduct can enter the second heatsink.

[0023] In this was the air rising through the airduct can cool the upper heatsink. Also, hot air exits the top of the upper heatsink and this in effect draws air out of the airduct such that the airflow through the airduct is further increased and both the lower heatsink and upper heatsink are more effectively cooled, leading to further improvement in the cooling of the circuit breaker.

[0024] At first sight this appears counterintuitive, because the upper heatsink is now being fed with the hot air that exits the lower heatsink. However, the inventors realised that the increase in velocity of the heated air that now passes through the upper heatsink improves the cooling of the upper heatsink over and above the situation when the airduct is not used, and the lower heatsink is also now further improved in its cooling as the air velocity has been further increased due to there now being a heatsink at both the top and bottom of the airduct.

[0025] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0026] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0027] In an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0028] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0029] In an example, the heatsink comprises aluminium and / or copper.

[0030] In an example, the second heatsink comprises aluminium and / or copper.

[0031] In an example, the heatsink comprises a plurality of fins or vanes.

[0032] In an example, the second heatsink comprises a plurality of fins or vanes.

[0033] There is provided a circuit breaker, comprising: a switching element; a first terminal; a second terminal; a heatsink; and an airduct.

[0034] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts.

[0035] The heatsink is connected to a first part of the circuit breaker.

[0036] A first open end of the airduct is connected to the heatsink, such that air exiting the airduct can enter the heatsink.

[0037] At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0038] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and rises. This then draws air into the airduct and there is a chimney effect, where air entering the heatsink is increased over that if the airduct was not present. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0039] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0040] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and thus they developed the airduct technique to increase the airflow through the heatsink.

[0041] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0042] In an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0043] In an example, the circuit breaker comprises an insulating pole housing, and the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0044] In an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0045] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0046] In an example, the circuit breaker comprises a second heatsink (6), wherein the heatsink is connected to a second part of the circuit breaker, wherein a second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the second heatsink can enter the airduct.

[0047] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0048] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0049] In an example, the heatsink comprises aluminium and / or copper.

[0050] In an example, the second heatsink comprises aluminium and / or copper.

[0051] In an example, the heatsink comprises a plurality of fins or vanes.

[0052] In an example, the second heatsink comprises a plurality of fins or vanes.BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Exemplary embodiments will be described in the following with reference to the following drawing: Fig. 1 shows an example of a circuit breaker without an airduct; and Fig. 2 shows an example of a circuit breaker with an airduct according to an embodiment of the invention. DETAILED DESCRIPTION OF EMBODIMENTS

[0054] Fig. 1 shows an example of a circuit breaker without an airduct

[0055] Fig. 2 shows an example of a circuit breaker with an airduct 8 according to an embodiment of the invention.

[0056] In Fig. 2 the airduct 8 is connected to both lower heatsink 7 and an upper heatsink 6. However, it could be connected to just the lower heatsink 7 or just connected to the upper heatsink 6.

[0057] It is also to be noted that in Fig. 2 the airduct 9 has an initial horizontal section leading from the lower heatsink 7 and then a vertical section and then another horizontal section leading into the upper heatsink 6. This is just for visualization, where to aid efficiency the airflow out of and into the heatsinks is parallel to vanes or fins of the heatsink.

[0058] However, the vanes or fins of either of both of the heatsinks could be oriented vertically and the one or other of the heatsinks could be offset. This means that the airduct 8 could be connected to the top of the lower heatsink 7 such that this end is vertically oriented and then be connected to the bottom of the upper heatsink 6 such that the airduct is oriented vertically along its length.

[0059] Or the airduct 8 could be connected to the side of the lower heatsink 7, have an initial horizontal section, then a vertical section and then be connected to the bottom of the upper heatsink 6.

[0060] Or the airduct 8 could be connected to the top of the lower heatsink 7, extend vertically and then be connected to the side of the upper heatsink 6 through a horizontal section.

[0061] The following relates to a number of different embodiments of the new development for cooling a circuit breaker.

[0062] According to an example, a circuit breaker, comprises: a switching element 2; a first terminal 1; a second terminal 1; a heatsink 7; and an airduct 8.

[0063] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts. The heatsink is connected to a first part of the circuit breaker. A first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct. At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0064] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and enters the airduct. The air rises in the airduct, and this draws cold air into the heatsink at a faster rate than if the hot air from the heatsink did not enter the airduct. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0065] In other words, the inventors realized that they could take the geometrical environment of the heatsink into account, in order to increase the efficiency of cooling of the heatsink.

[0066] To put this another way, the inventors determined that an important parameter of a heatsink's cooling capability relates to the velocity of the airflow through the heatsink, and then they developed the airduct technique to increase the airflow through the heatsink.

[0067] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0068] It is to be noted that when the two contacts have been brought together and are in contact with each other, the first terminal is again electrically connected to same terminal it was previously connected to and the second terminal is again electrically connected to the contact it was previously electrically connected to, but the two terminals are now also electrically connected to each other.

[0069] According to an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0070] According to an example, the circuit breaker comprises an insulating pole housing 4. The heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0071] According to an example, the circuit breaker comprises a second heatsink 6. The second heatsink is connected to a second part of the circuit breaker. A second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the airduct can enter the second heatsink.

[0072] In this was the air rising through the airduct can cool the upper heatsink. Also, hot air exits the top of the upper heatsink and this in effect draws air out of the airduct such that the airflow through the airduct is further increased and both the lower heatsink and upper heatsink are more effectively cooled, leading to further improvement in the cooling of the circuit breaker.

[0073] At first sight this appears counterintuitive, because the upper heatsink is now being fed with the hot air that exits the lower heatsink. However, the inventors realised that the increase in velocity of the heated air that now passes through the upper heatsink improves the cooling of the upper heatsink over and above the situation when the airduct is not used, and the lower heatsink is also now further improved in its cooling as the air velocity has been further increased due to there now being a heatsink at both the top and bottom of the airduct.

[0074] According to an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0075] According to an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0076] According to an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0077] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0078] According to an example, the heatsink comprises aluminium and / or copper.

[0079] According to an example, the second heatsink comprises aluminium and / or copper.

[0080] According to an example, the heatsink comprises a plurality of fins or vanes.

[0081] According to an example, the second heatsink comprises a plurality of fins or vanes.

[0082] In an example, a circuit breaker, comprises: a switching element 2; a first terminal 1; a second terminal 1; a heatsink 7; and an airduct 8.

[0083] The switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other. The two contacts are a fixed contact and a moveable contact. When the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts. The heatsink is connected to a first part of the circuit breaker. A first open end of the airduct is connected to the heatsink, such that air exiting the airduct can enter the heatsink. At least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

[0084] Thus, the inventors realized that the chimney effect can be utilized to effect improved cooling of a heatsink. The heatsink is connected to a hot part of the circuit breaker and itself becomes hots, and the air surrounding the heatsink become hot and rises. This then draws air into the airduct and there is a chimney effect, where air entering the heatsink is increased over that if the airduct was not present. Thus, cooling air flow through the heatsink is increased and the circuit breaker is more effectively cooled.

[0085] The airduct has a second open end of the airduct, at the opposite end of the airduct to the first open end, and the portion of the airduct oriented vertically or oriented at an angle to the vertical is a portion along a length of the airduct between the first open end and the second open end.

[0086] According to an example, the first part of the circuit breaker is adjacent to or part of the first terminal.

[0087] According to an example, the circuit breaker comprises an insulating pole housing 4. The heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

[0088] According to an example, the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

[0089] In an example, the angle is different to these angles, for example an intermediate angles to those detailed, and the shallow angle. The important effect is that the air rises within the airduct along its length from one open end to the other to the other, and this effect is most effective when the airduct or at least a portion of the airduct is oriented vertically.

[0090] In an example, the circuit breaker comprises a second heatsink (6), wherein the heatsink is connected to a second part of the circuit breaker, wherein a second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the second heatsink can enter the airduct.

[0091] In an example, the second part of the circuit breaker is adjacent to or part of the second terminal.

[0092] In an example, the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

[0093] In an example, the heatsink comprises aluminium and / or copper.

[0094] In an example, the second heatsink comprises aluminium and / or copper.

[0095] In an example, the heatsink comprises a plurality of fins or vanes.

[0096] In an example, the second heatsink comprises a plurality of fins or vanes.

[0097] The new development is now described in further specific detail, where reference is again made to Fig. 1 and Fig. 2.

[0098] The comparison of Fig. 1 and Fig. 2 shows the difference between both airflow situations, where the airflow is represented by the arrows. Both heatsinks are fed with air from their environment, heat it and accelerate it upwards and depending on their geometry. The addition of an airduct forces the air from the lower heatsink to run straight upwards which gains the effect of getting more cold air from underneath. The fast pre-heated air feeds the upper heatsink, where its high velocity is still capable of cooling the upper heatsink (in contrast to slow hot air). This makes the whole cooling more controlled, and both heatsinks more efficient.

[0099] Thus, the inventors started from the position where heatsinks are used to expose a big surface area to the environment, the heat transport takes place, when a certain airflow runs towards and from the heatsink. This means that for a smaller heatsink that is required in some situations when for example there is a space limitation, there is not enough surface to create such heat transport. The inventors then sought to make sure that enough air is able to flow into the heatsink and exits it easily too. This led to the realization to take the geometrical environment of the heatsink into account, with respect to utilization of the airduct described here.

[0100] The inventor's work established that one important parameter of a heatsink's cooling capability is the velocity of airflow inside. Known from chimneys, the heating of the air accelerates its flow, when it is guided in narrow compartments instead of simply being expose to open volumes.

[0101] As shown in Fig. 1, two heatsinks are arranged vertically to each other. Both have to dissipate heat, which leads to the situation that the airflow occurs in an uncontrolled manner and even the cooling capability of the upper heatsink can be decreased by being exposed to heated air from the lower heatsink.

[0102] The development shown in Fig. 2, with respect to one detailed embodiment, is to connect both heatsinks with an airduct, that takes up the air from the lower heatsink and guides it into the upper heatsink.

[0103] The inventors established that even while the upper heatsink is fed with pre-heated air, the air-guiding creates such a high flow velocity that the upper heatsink is ventilated properly to transport its heat away.

[0104] Thus, the new development made by the inventor relates to a vertical airduct being used to increase airflow through a heatsink, and to increase airflow through two heatsinks with common airduct between vertically arranged heatsinks. The development came about from the understanding that airflow to and from the heatsinks is a vital parameter to transport heat, and where airducts are used to guide the airflow and take advantage from the accelerated heated air.Reference Numerals

[0105] 1.Terminals of Main Circuit 2.Switching Element 3.Drive Housing 4.Insulating Pole Housing 6.Upper Heatsink 7.Lower Heatsink 8.Airduct from lower to upper Heatsink

Examples

Embodiment Construction

[0054]Fig. 1 shows an example of a circuit breaker without an airduct

[0055]Fig. 2 shows an example of a circuit breaker with an airduct 8 according to an embodiment of the invention.

[0056]In Fig. 2 the airduct 8 is connected to both lower heatsink 7 and an upper heatsink 6. However, it could be connected to just the lower heatsink 7 or just connected to the upper heatsink 6.

[0057]It is also to be noted that in Fig. 2 the airduct 9 has an initial horizontal section leading from the lower heatsink 7 and then a vertical section and then another horizontal section leading into the upper heatsink 6. This is just for visualization, where to aid efficiency the airflow out of and into the heatsinks is parallel to vanes or fins of the heatsink.

[0058]However, the vanes or fins of either of both of the heatsinks could be oriented vertically and the one or other of the heatsinks could be offset. This means that the airduct 8 could be connected to the top of the lower heatsink 7 such that this e...

Claims

1. A circuit breaker, comprising: - a switching element (2); - a first terminal (1); - a second terminal (1); - a heatsink (7); and - an airduct (8); wherein the switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other, wherein the two contacts are a fixed contact and a moveable contact, and wherein when the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts; wherein the heatsink is connected to a first part of the circuit breaker; wherein a first open end of the airduct is connected to the heatsink, such that air exiting the heatsink can enter the airduct; and wherein at least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

2. Circuit breaker according to claim 1, wherein the first part of the circuit breaker is adjacent to or part of the first terminal.

3. Circuit breaker according to any of claims 1-2, wherein the circuit breaker comprises an insulating pole housing (4), and wherein the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

4. Circuit breaker according to any of claims 1-3, wherein the circuit breaker comprises a second heatsink (6), wherein the second heatsink is connected to a second part of the circuit breaker, wherein a second open end of the airduct, at the opposite end of the airduct to the first open end, is connected to the second heatsink, such that air exiting the airduct can enter the second heatsink.

5. Circuit breaker according to claim 4, wherein the second part of the circuit breaker is adjacent to or part of the second terminal.

6. Circuit breaker according to any of claims 4-5 when dependent upon claim 3, wherein the second heatsink is connected to the second part of the circuit breaker through the insulating pole housing.

7. Circuit breaker according to any of claims 1-6, wherein the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

8. Circuit breaker according to any of claims 1-7, wherein the heatsink comprises aluminium and / or copper.

9. Circuit breaker according to any of claims 4-8, wherein the second heatsink comprises aluminium and / or copper.

10. Circuit breaker according to any of claims 1-9, wherein the heatsink comprises a plurality of fins or vanes.

11. Circuit breaker according to any of claims 4-10, wherein the second heatsink comprises a plurality of fins or vanes.

12. A circuit breaker, comprising: - a switching element (2); - a first terminal (1); - a second terminal (1); - a heatsink (7); and - an airduct (8); wherein the switching element comprises two contacts configured to be brought into contact with each other and configured to be separated from each other, wherein the two contacts are a fixed contact and a moveable contact, and wherein when the two contacts are separated from each other the first terminal is electrically connected to one of the two contacts and the second terminal is electrically connected to the other of the two contacts; wherein the heatsink is connected to a first part of the circuit breaker; wherein a first open end of the airduct is connected to the heatsink, such that air exiting the airduct can enter the heatsink; and wherein at least a portion of the airduct is oriented vertically or oriented at an angle to the vertical.

13. Circuit breaker according to claim 12, wherein the first part of the circuit breaker is adjacent to or part of the first terminal.

14. Circuit breaker according to any of claims 12-13, wherein the circuit breaker comprises an insulating pole housing (4), and wherein the heatsink is connected to the first part of the circuit breaker through the insulating pole housing.

15. Circuit breaker according to any of claims 12-14, wherein the angle to the vertical is 5 degrees, 10 degrees, 15 degrees, 20 degrees, or 25 degrees.

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