EP2544206B1 - Circuit breaker - Google Patents

Description

The invention relates to a circuit breaker with a short-circuit release and a thermal overload release, the short-circuit release having an armature and a pole, which are arranged within a bobbin, and a yoke plate and a terminal connection, which are arranged around the bobbin, and wherein the thermal overload release a metal strip of at least two types of metal, around which a heating conductor is wound, wherein between the heating conductor and metal strip, an electrical insulator is arranged.

Circuit breakers with such short-circuit releases are used for switching and protecting motors and other consumers. These short-circuit releases are designed as electromagnetic triggers that essentially comprise a coil winding, a bobbin, an armature, a pole, a plunger, a retaining spring and a yoke. The armature will pick up at a certain rated current of the circuit breaker, for example, 12 times the nominal current for motor protection or a 19 times the rated current for transformer protection. The armature movement acts on a switch lock and on a movable contact piece to open the contacts. Normally, the operating current may fluctuate by a maximum of +/- 20%.

For larger adjustment ranges, the difficulty is because of the required larger support cross-sections, smaller numbers of turns, greater tolerances of the coil and the winding wire and the associated inhomogeneous magnetic magnetic field, the coil winding to the air gap between the armature and yoke sufficiently accurately position so that the response limits according to standard can be complied with. There is also the problem of fixing the coil winding in the once determined position to the air gap, so that at the rated current and high short-circuit current no shifting the coil winding is in the direction of the center of gravity iron or the coil contracts and deformed and then the response limits are no longer met.

At higher switching powers, the coils are made with adjacent winding turns to prevent the coil from contracting and deforming at high short circuit currents. Due to the use of uniform bobbin for each size and its interpretation for the largest geometric coil winding, often creates a gap between Spulenkörperflansch or yoke and the last turn of the coil winding. After the exact positioning of the coil winding to the air gap between the armature and the yoke, one end of the coil is glued to the bobbin flange or yoke to fix the coil winding, and the other end of the coil is welded to the connection.

For circuit breakers with a high switching capacity, for example up to 100 kA with a rated current of 80 A, the short-circuit release must be adapted. Due to the high switching capacity of an 80A device, the heat budget is critical. In addition, due to the increasing contact load also increases the power requirement on the trigger. Assuming that the trigger does not have more power than today's 50A releases with the same excitation, the magnetic circuit must be built more efficiently.

Today's switching devices have a poorer magnetic circuit, since the yoke plate is simultaneously formed as a bimetal and is made of a platinum-plated material, a pair of iron and copper.

So far, this problem has been solved by a poorer magnetic circuit by means of a platinum-plated copper steel sheet and a corresponding arrangement of the parts. In addition, partially bonded materials can be produced and then formed into the required material pairing. Likewise, different yoke plates are used, which enclose the core of the trigger, consisting of armature and pole, in order to achieve a triggering effect in conjunction with the coil. The strength level of these triggers is maintained by a high-level excitation. This means inefficient energy conversion between electrical to mechanical energy.

This describes the EP 2 204 834 A2 a circuit breaker with a short-circuit release and a thermal overload release, the short-circuit release having an armature and a pole disposed within a bobbin, and a yoke plate and a terminal terminal, which are arranged around the bobbin, and wherein the thermal overload release of a metal strip has at least two types of metal, around which a heating conductor is wound, wherein between the heating conductor and metal stiffeners, an electrical insulator is arranged, wherein the connection of the thermal overload release is carried out on the yoke plate by means of a separate angle.

Accordingly, the object of the present invention is to provide a circuit breaker with a short-circuit release and a thermal overload release that shows a defined tripping behavior at high switching performance at an optimized thermal stress.

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.

The attachment according to the invention of the thermal overload release on the yoke plate via a separate angle is preferably designed rigid. This includes the fixed connection between the separate angle, in particular one Steel angle and the yoke plate. The rigid version can preferably be achieved by a steel angle, which has an embossment for stiffening. In addition, it is possible to make the connection between the thermal overload release, ie between the metal strip, which is preferably designed as a bimetal and the separate angle by a weld, which is arranged offset in height.

In a particularly advantageous embodiment, the connection of the steel angle to the yoke plate is carried out by stop lugs or pins.

It is also conceivable to carry out the connection of the steel angle to the yoke plate without stop lugs or pins or to manufacture the steel angle without embossing or beading. This means that a re-evaluation of the design with regard to tolerances, torque, materials and bending behavior is necessary.

According to the invention it is also provided that the fixation is made via a correspondingly adapted mold cavity. This mold nest can also be used as a sweat receptacle to join both parts. The connection between the thermal overload release, ie between the bimetal and the separate angle, can be done for example by a Laserscheißung, in which one or more longitudinal seams are realized, which are arranged vertically to each other. The connection can also be implemented with another welding method, for example resistance welding or tungsten inert gas welding (TIG welding). It is also conceivable to solder the connection or to use screws.

It is particularly advantageous to use the separate angle in edgewise form, since in this way a stiffer overall system is formed. The thermal release is carried out more rigid overall. It is also advantageously provided that the height of the separate angle varies be able to take account of the increased continuous load. In a particularly advantageous embodiment, it is provided that the direct connection between the separate angle and the bimetal is implemented via a pocket in a separate angle in order to ensure the exact positioning. After positioning, the parts are joined together. In a further step, the coil is combined with the bimetal. This too can be implemented by known welding methods. In particular, it is provided that an adapted shaping of the coil between the coil end and the bimetal leads to a parallelism, which facilitates the connection of the two parts.

The circuit breaker according to the invention is characterized in that the attachment of the thermal overload release, so the bimetallic strip on the yoke plate of the short-circuit release is carried out by means of an additional part in the form of a separate angle. The fixation of the separate angle, in particular a steel angle to the yoke plate, can be done via punched stops or pins in the yoke plate. As a connection technique, inter alia, between laser shearing, TIG welding, soldering, resistance welding or screws can be selected. The rigid connection between the separate angle and the yoke plate can be achieved on the one hand by embossing in a separate angle, on the other hand by means of a height-offset welding of the bimetal at an angle. Overall, this leads to a stiffening of the entire system of the trigger. Another advantage is that the separate angle serves as a fixed positioning for the connection of the winding coil of the short-circuit release. In addition, the separate angle can serve as a height stop and fixation for the entire system of the power release module in an adapted upper part or in a chamber by its individual shape. Further advantages of the circuit breaker according to the invention are that the separate angle can be used as bulk material and material is saving, so that overall cost savings is given.

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 Darstellung ein Ausführungsbeispiel einer erfindungsgemäßen Verbindung zwischen einem thermischen Überlastauslöser und einem Jochblech eines Leistungsschalters über einen separaten Winkel;
• Fig. 2 in einer perspektivischen Darstellung das Ausführungsbeispiel nach Fig. 1 in der Ansicht von hinten;
• Fig. 3 in einer perspektivischen Darstellung ein Ausführungsbeispiel eines separaten Winkels mit Prägung und Anschlägen am Jochblech zur Positionierung;
• Fig. 4 in einer perspektivischen Darstellung ein Ausführungsbeispiel eines separaten Winkels mit Prägung und Zapfen am Jochblech zur Positionierung;
• Fig. 5 in einer perspektivischen Darstellung ein Ausführungsbeispiel eines separaten Winkels mit Prägung und Tasche zur Aufnahme und Anbindung des thermischen Überlastauslösers;
• Fig. 6 in einer perspektivischen Darstellung das Ausführungsbeispiel nach Fig. 5 um 90° gedreht;
• Fig. 7 in einer perspektivischen Darstellung ein weiteres Ausführungsbeispiel eines separaten Winkels mit Materialfortsatz.

Here are shown schematically:

• Fig. 1 in a perspective view of an embodiment of a compound according to the invention between a thermal overload release and a yoke plate of a circuit breaker via a separate angle;
• Fig. 2 in a perspective view of the embodiment Fig. 1 in the view from behind;
• Fig. 3 in a perspective view of an embodiment of a separate angle with embossing and stops on the yoke plate for positioning;
• Fig. 4 in a perspective view of an embodiment of a separate angle with embossing and pin on the yoke plate for positioning;
• Fig. 5 in a perspective view of an embodiment of a separate angle with embossing and pocket for receiving and connecting the thermal overload release;
• Fig. 6 in a perspective view of the embodiment Fig. 5 turned by 90 degrees;
• Fig. 7 in a perspective view of another embodiment of a separate angle with material extension.

Fig. 1 shows an embodiment of a connection according to the invention between a thermal overload release 1, which has a metal strip 2 of at least two types of metal and a heating element 3, which is wound around the metal strip 2, and a yoke plate 4 of the short-circuit release a circuit breaker. The connection according to the invention between the metal strip 2, preferably a bimetallic strip and the yoke plate 4, is designed as an additional part in the form of a separate angle 5. The separate angle 5 is preferably L-shaped with two legs 6, 7, which are connected to each other via a curved portion 8. The legs 6, 7 may preferably have different lengths. The leg 6 of the separate angle 5 is connected via its surface with the yoke plate 4, for example by a welded connection or by soldering. Similarly, the leg 7 of the separate angle 5 is connected via parts of its surfaces with the metal strip 2 of the thermal release 1. The legs 6, 7 are preferably at an angle of 90 ° to each other.

In Fig. 2 is the embodiment after Fig. 1 shown in a view from behind. On the leg 7 of the separate angle 5, a material recess 9 is formed, which is arranged centrally and extends longitudinally over the leg 7.

Fig. 3 shows an embodiment of a separate angle 5, which has an embossment 10 and is positioned over stops 11 on the yoke plate 4. The embossment 10 is formed over the entire leg 6, the bent portion 8 and partially over the leg 7. The embossing 10 serves to stiffen the overall system of thermal overload release and short-circuit release.

In Fig. 4 a further embodiment of a separate angle 5 is shown with embossment 10, wherein the embossment 10 is here only partially formed on the legs 6, 7 and in the bent portion 8. For positioning 4 pins 12 are formed on the yoke plate, which engage in recesses of the separate angle 5.

Fig. 5 shows a further embodiment of a separate angle 5 with embossment 10, wherein the embossment 10 here only in bent portion 8 of the L-shaped separate angle 5 is formed. The separate angle 5 also has on the leg 7 a pocket in the form of a recess 13 which serves to receive and connect the thermal overload release 1. In addition, the leg 6 of the separate angle 5 is arranged in this embodiment edgewise on the yoke plate 4 and thus offset by 90 ° to the embodiments of the Fig. 1 to 4 , It follows that the connection to the thermal overload release 1 is not made over the surface of the leg 7 of the separate angle 5, but via the recess 12 which is incorporated in the leg 7.

In Fig. 6 is the embodiment after Fig. 5 shown rotated by 90 ° in a representation. Here, the arrangement between the leg 7 of the separate angle 5, the thermal overload release in the form of its metal strip 2 and a coil extension 14 of an adjacent short-circuit release is shown. The Fig. 6 shows the recess 13 for the metal strip 2 in a front view. Out Fig. 6 also shows the parallel arrangement of leg 7 of the separate angle 5, metal strip 2 and coil extension 14 out.

In Fig. 7 a further embodiment of a separate angle 5 according to the invention is shown, wherein here at the lower side edge of the leg 7, a preferably curved material extension 15 is formed, which serves as a support surface for the coil extension 14.

The circuit breaker according to the invention is characterized in that the attachment of the thermal overload release, ie the bimetal, on the yoke plate of the short-circuit release is carried out by means of an additional part in the form of a separate angle. The fixation of the separate angle, in particular a steel angle to the yoke plate, can be done via punched stops or pins in the yoke plate. As connection technology, it is possible to choose between laser shearing, TIG welding, soldering, resistance welding, screws or rivets. The rigid connection between the separate Angle and the yoke plate can be achieved on the one hand by an embossing in a separate angle, on the other hand by means of a height-offset welding of the bimetal at an angle. Overall, this leads to a stiffening of the entire system of the trigger. Another advantage is that the separate angle serves as a fixed positioning for the application of the winding coil of the short-circuit release. In addition, the separate angle can serve as a height stop and fixation for the entire system of the power release module in an adapted upper part or in a chamber by its individual shape. Further advantages of the circuit breaker according to the invention are that the separate angle can be used as bulk material and material is saving, so that overall cost savings is given.

Claims (8)

1. Circuit breaker comprising a short-circuit release and a thermal overload release (1), wherein the short-circuit release has an armature and a pole, which are arranged within a coil former, and also a yoke plate (4) and a terminal connection, which are arranged around the coil former, and wherein the thermal overload release (1) has a metal strip (2) which is composed of at least two types of metal and around which a heating conductor (3) is wound, wherein an electrical insulator is arranged between the heating conductor (3) and the metal strip (2), wherein the connection of the thermal overload release (1) to the yoke plate (4) is implemented by means of a separate bracket (5), wherein the separate bracket (5) is of L-shaped design with two limbs (6, 7), characterized in that one limb (6) of the separate bracket (5) is connected to the yoke plate (4) by means of its surface, and the other limb (7) of the separate bracket (5) is connected to the metal strip (2) of the thermal release (1) by means of parts of its surface.
2. Circuit breaker according to Claim 1, characterized in that the connection between the yoke plate (4) and the separate bracket (5) and also between the separate bracket (5) and the thermal overload release (1) is implemented as a weld connection.
3. Circuit breaker according to Claim 1 or 2, characterized in that the weld connection is implemented as a laser weld connection, tungsten inert gas weld connection or resistance weld connection.
4. Circuit breaker according to Claim 1 or 2, characterized in that the connection between the yoke plate (4) and the separate bracket (5) and also between the separate bracket (5) and the thermal overload release (1) is soldered.
5. Circuit breaker according to one of the preceding claims, characterized in that the separate bracket (5) is positioned on the yoke plate (4) by means of stops (11).
6. Circuit breaker according to one of the preceding claims, characterized in that the separate bracket (5) is positioned on the yoke plate (4) by means of pins (12).
7. Circuit breaker according to one of the preceding claims, characterized in that the separate bracket (5) has an embossing (10) for reinforcing the overall system comprising the short-circuit release and the thermal overload release (1).
8. Circuit breaker according to one of the preceding claims, characterized in that the separate bracket (5) has a recess (13).

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