EP2573789B1 - Circuit breaker with ventilation channels for efficient heat dissipation - Google Patents

Description

Circuit breaker with ventilation ducts for efficient heat dissipation
The invention relates to a circuit breaker comprising a housing in which a first switching device area, in which a quenching chamber device and a contact slide device are arranged with movable contact pieces, which are positioned opposite to Festschaltstücken, and a second switching device area are arranged, in which a current release group of a short-circuit release and an overload release are arranged.

Circuit-breakers, in particular low-voltage circuit breakers, are electromagnetic self-switches in the event of a short circuit. Their operation corresponds in principle to the operation of circuit breakers. They are usually equipped with a thermal and a magnetic release and thus have the same structural elements as circuit breakers. However, they are designed for larger rated currents, in addition, the triggers of circuit breakers, unlike the circuit breaker, sometimes separately adjustable. In the low voltage range, the switches are also used as motor protection switches.

A circuit breaker with a separate housing in two areas is in EP-A-1471553 disclosed.

The task of the circuit breaker is to protect downstream systems and in particular three-phase motors against damage due to overload or short circuit. The circuit breaker should switch off these currents in conjunction with the network protection devices. If there is gas between the two poles, it will be ionized by the flashover with a correspondingly high voltage difference between the poles, forming a self-sustaining gas discharge, also known as an arc. This plasma not only continues to conduct power, but also reduces the life of the device, and at high currents it can even destroy the switch. In contrast to disconnectors are circuit breakers designed so that the arcing occurring when opening the switch contacts deleted quickly and without damaging the switch and thus the flow of current is interrupted.

Circuit-breakers are developed in various sizes. A size is composed of device variants with a meaningful successive build-up nominal current series, the power loss is approximately proportional to the square of the rated current. The device variant with the highest rated current for a given size is determined by the fact that just for this stream the power loss with the appropriate housing volume remains without adverse consequences for the requirements of the switching device over its lifetime. If you want to get even higher rated currents, you develop a larger design. From the customer's point of view, however, it is desirable to increase the maximum rated current within one size even further. To achieve this, measures must be taken to make the removal of heat from the housing volume technically more efficient.

In principle, there are two options for dealing with high temperatures within a protective housing due to unavoidable electrical power loss. One possibility is to optimize all materials so that they meet their functional requirements, even at a high temperature level. However, this is a very expensive solution.

The other possibility is to force the removal of the heat generated from the housing by technical measures. For electronic products, active cooling measures by means of a case fan, heat pipe arrangement or even coolant circuits are state of the art. In order to be able to dissipate locally generated large amounts of heat and thus, these amounts of heat are distributed by means of heat sinks on large areas.

In electromechanical switching devices such heat sinks are unsuitable. Here, the heat is dissipated in addition to the connecting lines mainly on the freely accessible device surfaces, essentially top side, feed and device outlet side. This leads in practice due to the long heat path often to a high device temperature level and disadvantageous relatively concentrated hot springs.

Accordingly, the object of the present invention is to provide a circuit breaker that enables efficient heat dissipation without additional heat sink.

This object is achieved by a circuit breaker having the features of patent claim 1. Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

According to the invention, this object is achieved by a circuit breaker having a first switching device area, in which a quenching chamber device and a contact slide device are arranged with movable contact pieces, which are positioned opposite to Festschaltstücken, and a second switching device area in which a current release group of a short-circuit release and an overload release arranged are. The invention is characterized in that a continuous ventilation channel is formed within opposing housing walls along the Festschaltstücke as the first convective air flow through the power switch for heat dissipation.

According to the invention, the heat is dissipated, in addition to the device surfaces, via a through-duct with a large cross-section extending from the feed side through the device to the outlet side. In the preferred installation position, that is, the assembly takes place on a vertical wall, the Infeed is at the top, the outlet is at the bottom, air from below into openings provided air loss heat directly from some of the main loss of power generators record, that is, from contact points and current paths, and transport in the feed side and out there to the air.

According to the invention, a first convective air flow is provided along the fixed contact pieces. The convective air flow along the Festschaltstücke is ensured by a structural transformation of the Festschaltstücke, the contact slide device and the covers on the Festschaltstücken. The principle is to obtain a significant flow cross-section. All outward sealing elements are removed or redesigned. At the same time, the open cross-section between the flow cross-section and the switching chamber is kept as low as possible by a corresponding constructive redesign.

Structurally, the fixed switching pieces are U-shaped with two legs and a connecting the two legs transition area. The transition region is designed such that two horned contours are parallel to each other and spaced from a recess. The horned contours of the fixed contact pieces engage in contours of the switch inner housing and thus contribute in the event of a short circuit to the stabilization of the entire circuit breaker. In the recess of the transition region of the Festschaltstückes a leg extension is formed in the form of a nose, which increases the contact bearing surface for the underside arranged on the leg contact. In particular, this Schenkenfortsatz the Festschaltstückes causes the open cross-section between the ventilation duct and switching chamber is kept as low as possible.

In addition, the contact slide has a recess in the form of a perforation or breakthrough or simply U-shaped open towards the top, in the height of the recess the Festschaltstücke is arranged and thus forms a complete ventilation duct on the Festschaltstücke and the contact slide, which is completed by covers on the Festschaltstücken and finally via openings in the housing. Thus, overall, a first convective airflow along the fixed contact pieces results through recesses on the contact slide device, on the fixed contact pieces and on the covers which are arranged on the fixed contact pieces, which form a total of a ventilation channel, which allows the heat dissipation through openings in the housing.

According to the invention, a second convective air flow is preferably formed in the L-side connection region, which branches off from the first convective air flow along the fixed contact pieces into the second switching device region and enables heat removal via a terminal connection and openings in the housing. Heat is also absorbed via the terminal as this flow past.

In addition, a third convective air flow in the T-side connection region is preferably formed, which is formed via a channel at the terminal connection and allows the heat dissipation through openings in the housing. This convective airflow in the T-side connection area flows into the switch and passes through a channel on the hot terminal. He absorbs heat and then leaves the switch through openings in the housing.

In a particularly advantageous embodiment it is provided that dirt-collecting elements are arranged in the ventilation channel, which are designed such that they protect the circuit breaker from dirt, without preventing the air flow. This dirt receiving element is preferably formed as a grid or arranged as a succession of surfaces that appear closed in the projected view, and thus prevent incoming dirt, but allow air circulation.

The present invention is characterized in that a continuous ventilation channel is formed within opposing housing walls along the Festschaltstücke as the first convective air flow through the power switch for heat dissipation. Preferably, two more convective air streams are provided in the L-side connection region and in the T-side connection region. By means of these convective air flows according to the invention, greater power losses can be dissipated, so that higher rated current densities of the circuit breaker are made possible with the same construction volume. Due to the conception according to the invention, with a design of power switches arranged next to one another, it is avoided that heat release surfaces or openings are covered. With the same device size, the heat dissipation concept presented here leads to a significant reduction in the temperature level.

Further advantages and embodiments of the invention will be explained below with reference to embodiments and with reference to the drawing.

• Fig. 1 in einer perspektivischen Schnittdarstellung einen Aufbau eines erfindungsgemäßen Leistungsschalters mit drei konvektiven Einzelströmen für den Wärmeabtransport;
• Fig. 2 in einer perspektivischen Darstellung eine erfindungsgemäße Anordnung aus Kontaktschiebervorrichtung, Festschaltstücken und Abdeckung;
• Fig. 3 in einer perspektivischen Darstellung einen Teilbereich eines L-seitigen Anschlussbereichs mit Klemme;
• Fig. 4 in einer perspektivischen Darstellung einen Teilbereich eines T-seitigen Anschlussbereichs mit Klemme;
• Fig. 5 in einer Schnittdarstellung die Löschkammervorrichtung des Leistungsschalters mit Kontaktschiebervorrichtung und Festschaltstücken;
• Fig. 6 in einer Draufsicht die Anordnung aus Festschaltstücken und Kontaktschiebervorrichtung.

Here are shown schematically:

• Fig. 1 in a perspective sectional view of a structure of a circuit breaker according to the invention with three convective individual streams for heat dissipation;
• Fig. 2 in a perspective view of an inventive arrangement of contact slide device, Festschaltstücken and cover;
• Fig. 3 in a perspective view, a portion of an L-side terminal area with terminal;
• Fig. 4 in a perspective view, a portion of a T-side connection area with terminal;
• Fig. 5 in a sectional view of the extinguishing chamber device of the circuit breaker with contact slide device and Festschaltstücken;
• Fig. 6 in a plan view of the arrangement of Festschaltstücken and contact slide device.

Fig. 1 shows the structure of a circuit breaker according to the invention with a preferably two-part housing, in which a first switching device area 1 in a housing lower part 2 and a second switching device area 3 are arranged in a housing upper part 4. In the first switching device area 1, a quenching chamber device 5 is arranged with superposed quenching plates 6 and centrally between the two splitter stack a contact slide device 7 with a positioned on a spring 8 movable contact piece 9. The movable contact piece 9 is opposite to Festschaltstücken 10 arranged. The fixed contact pieces 10 are preferably U-shaped with two legs 11, 12 which are interconnected by a transition region 13. The transition region 13 of the fixed contact pieces 10 is preferably formed in the form of horned contours 14, which are preferably web-shaped and are spaced from each other by a recess 15. The horned contours 14 engage in contours 16 of the housing inner wall of the circuit breaker, so that in the case of a short circuit, the housing is stabilized.

Above the contact slide device 7 in the second switching device area 3, a short-circuit release 17 is arranged. The short-circuit release 17 has a carrier part 18, preferably made of plastic, in which an armature 19 with a plunger 20, which is arranged within a pole 21 and projects into the contact slide device 7, is located. To the support member 18, a coil 22 is wound. The coil 22 is surrounded by a yoke 23 and a magnetic plate 24. Above the short-circuit release 17, a switching mechanism 25 is arranged. In addition to the short-circuit release 17 is an overload release 26 having a bimetal 27 around which a heating conductor 28 is wound. In each case laterally above the splitter stack in the upper housing part 4 are clamping connections 29, 30th

The circuit breaker according to the invention is characterized by the fact that the convective air flow through the circuit breaker for heat dissipation from preferably three individual streams is put together. According to the invention, a first convective air flow is provided along the fixed contact pieces 10. The convective air flow along the fixed contact pieces 10 is achieved by a structural redesign of the fixed contact pieces 10, the contact slide device 7 and a cover 31 which is positioned on the fixed contact pieces 10. The principle is to obtain a significant flow cross-section. All outward sealing elements are removed or redesigned. At the same time, the open cross-section between the flow cross-section and the switching chamber is kept as low as possible by a corresponding constructive redesign.

Structurally, the fixed switching pieces 10 are U-shaped with the two legs 11, 12 and the two legs 11, 12 connecting transition region 13. The transition region 13 in this case has the horned contours 14, which are arranged parallel opposite the recess 15.

The contact slide device 7 has a recess 32 in the form of a through hole, which is arranged in the height of the recess 15 of the Festschaltstücke 10 and thus forms a complete ventilation channel 33 via the Festschaltstücke 10 and the contact slide device 7, via the cover 31 on the Festschaltstücken 10 and finally completed via openings 34 in the housing. Thus, a total of a first convective air flow along the Festschaltstücke 10 by recesses 15, 32 results in the contact slide device on the Festschaltstücken and on the cover 31, which are arranged on the Festschaltstücken 10, which together form a ventilation channel 33, which allows the heat dissipation through the opening 34 in the housing.

According to the invention, a second convective air flow 35 is formed in the L-side connection region, which branches off from the first convective air flow along the fixed contact pieces 10 into the second switching device region 3 and enables heat removal via a terminal connection 29 and openings 36 in the housing. Heat is also absorbed via the terminal as this flow past.

In addition, a third convective air flow 37 is formed in the T-side connection region, which is formed via a channel 38 at the terminal connection 30 and allows the heat dissipation through openings 39 in the housing. This convective airflow in the T-side connection area flows into the switch and passes through a channel on the hot terminal. He absorbs heat and then leaves the switch through openings 39 in the housing.

In Fig. 2 an arrangement according to the invention of the contact slide device 7, the Festschaltstücken 10 and the cover 31 is shown on the Festschaltstücken 10, which allow the first convective air flow. The fixed contact pieces 10 are U-shaped with the two legs 11, 12, which are connected to each other via a transition region 13. The transition region 13 of the fixed contact pieces 10 is formed with horned contours 14, which are preferably web-shaped and are spaced from each other by the recess 15. The horned contours 14 engage in the mounted state in the circuit breaker in counter contours 16 of the housing inner wall of the circuit breaker, so that in the case of a short circuit, the housing is stabilized. The cover 31 on the Festschaltstücken 10 is provided with recesses 40, so that a complete ventilation is possible. In addition, the recess 32 is on the contact slide device 7 in height of the recess 15 on the Festschaltstücken 10 in Fig. 2 to see.

Fig. 3 shows a portion of an L-side connection area of a circuit breaker with terminal. The convective airflow 35 in the L-side connection region branches off from the current along the fixed contact pieces 10. He pulls past the terminal over an open cross-section in the switch. Then he leaves the switch via openings 36 in the upper housing part 4 and lower housing part, while flowing past the terminal. In the course of this flowing past heat is absorbed again via the terminal.

Fig. 4 shows a partial area of a T-side connection area with terminal. The convective airflow 37 in the T-side port area flows into the switch and then passes through the channel 38 at the hot terminal. He absorbs heat and then leaves the switch through openings 39 in the housing wall.

In Fig. 5 the quenching chamber device 5 with contact slide device 7 and fixed switching pieces 10 is shown. In particular, the formation of the fixed contact pieces 10 allows a seal between the ventilation channel 33 and the switching chamber. This is in Fig. 6 illustrated that the leg 11 forms a leg extension in the form of a nose 41, which extends to the contact slide device 7. By this nose 41 on the one hand the contact surface for the contacts below the leg is increased. On the other hand, the open cross section 42 to the switching chamber is thereby minimized, so that a seal between the ventilation channel 33 and switching chamber is possible.

The present invention is characterized in that a continuous ventilation channel is formed within opposing housing walls along the Festschaltstücke as the first convective air flow through the power switch for heat dissipation. Preferably still are Two additional convective air streams are provided in the L-side connection area and in the T-side connection area. By means of these convective air flows according to the invention, greater power losses can be dissipated, so that higher rated current densities of the circuit breaker are made possible with the same construction volume. Due to the conception according to the invention, with a design of power switches arranged next to one another, it is avoided that heat release surfaces or openings are covered. With the same device size, the heat dissipation concept presented here leads to a significant reduction in the temperature level.

Claims (3)

1. Circuit breaker having a housing, in which a first switching device region (1), in which a quenching chamber apparatus (5) and a contact slide apparatus (7) with moving switching pieces (9) are arranged, said switching pieces being positioned opposite fixed switching pieces (10), and a second switching device region (3) are arranged, in which a current release group comprising a short-circuit release (17) and an overload release (26) are arranged, characterized in that a continuous ventilation channel (33) is formed within opposite housing walls along the fixed switching pieces (10), wherein the fixed switching pieces (10) are of U-shaped design and have two limbs (11, 12) which are connected to one another by a transition region (13), wherein the transition region (13) is designed in the form of horned contours (14) which are designed in a web-like manner and are spaced apart from one another by a recess (15), and wherein the contact slide apparatus (7) has a recess (32) which is arranged level with the recess (15) in the fixed switching pieces (10) and therefore forms a complete continuous ventilation channel (33) across the fixed switching pieces (10) and the contact slide apparatus (7), said continuous ventilation channel being completed by means of an opening (34) in the housing.
2. Circuit breaker according to Claim 1, characterized in that the horned contours (14) engage in mating contours (16) in the switching housing.
3. Circuit breaker according to Claim 1 or 2, characterized in that lugs (41) are formed on the fixed switching pieces (10).

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