EP2544208B1 - Short circuit trigger with optimised magnet circuit - Google Patents

Description

The invention relates to a short-circuit release, in particular for a circuit breaker with an armature and a pole, which are arranged within a bobbin, and a yoke plate and a clamping connection, which are arranged around the bobbin.

Such short-circuit releases are used in circuit breakers 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, larger tolerances of the coil of the winding wire and the associated inhomogeneous magnetic magnetic field, the coil winding to position the air gap between the armature and pole sufficiently accurate, so that the response limits complied with the standard can be. In addition, there is the problem of fixing the coil winding in the position once determined to the air gap, so that at the rated current and high short-circuit current does not shift the coil winding in the direction of the center of gravity or the coil contracts and deformed and thus 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 a 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 80 A 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 dissipation than the current 50 A trigger with correspondingly 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, made of material, for example, 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. Furthermore, partially bonded materials can be produced and then formed appropriately arranged for the required material pairing. Likewise, other yoke plates are used, which are the core of the trigger, consisting of anchor and Enclose pole in order to achieve a triggering effect in interaction 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 goes from the US Pat. No. 2,840,663 a short-circuit release for a circuit breaker, wherein the short-circuit release with an armature and a pole, which are arranged within a bobbin, and a yoke plate and a terminal terminal, which are arranged around the bobbin, is provided, wherein the terminal terminal opposite to the yoke plate is arranged.

Accordingly, the object of the present invention is to provide a short-circuit release, in particular for a circuit breaker having an improved magnetic circuit at a high switching capacity.

This object is achieved by a short-circuit release 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 short-circuit release, in particular for a circuit breaker, with 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. The invention is characterized in that opposite to the yoke plate at the terminal connection fitting, a magnetic plate is arranged.

The feature essential to the invention is the arrangement of yoke plate and magnetic plate to each other, made of two separate parts without direct connection to the terminal connection. The terminal connection is also made as a single part, the takes over the function as a current path. The additional magnetic sheet according to the invention substantially reduces the magnetic loss. This arrangement of the non-platinum-plated magnetic sheet is placed only in the area where it is magnetically required. With a platinized strip material, such as copper, iron, the assignment is partially not possible. Here the terminal connection would be continuous made of platiniertem molding material. A partial combination of two materials by means of, for example, runway welding, can not be used, since the introduced heat for welding the metal structure would be changed so that the effects on the magnetic circuit would be unacceptable. Also, the high cost of the starting material are crucial for the division of magnetic plate and terminal connection.

Here, the positive pairing of magnetic sheet and terminal connection is essential. Preferably, a depression or embossing is arranged in the magnetic sheet. This is arranged axially parallel to the axial center of the short-circuit release to allow the required space for the adjacent coil turns. Here, the required cross section can vary as far as required by the design of the coil. This also allows to optimize the installation space in the overall unit and to allow manufacturing tolerances. A corresponding clearance in the terminal connection is a prerequisite for the implementation of the embossing on the magnetic sheet.

Another significant advantage is that the individual pairing of parts an unnecessary loss in the current path can be avoided.

It is also possible to form a recess on the magnetic sheet. Due to the individual pairing of parts, this separate recess can be made. This allows for an optimized welded joint and a lower electrical resistance, as this can be used to weld two similar materials, in the present case the coil and the terminal connection. A welding directly on the magnetic sheet or a platinized strip material causes a significant deterioration of the magnetic circuits. In addition, increased manufacturing costs may arise due to a possible additional welding. Another advantage is that the terminal connection provides the path from the coil to the terminal connects, whereby the temperature at the terminal can be lowered by the long way from the current path.

Preferably, a recess is also provided on the terminal connection, can be compensated by the supernatants by welding beads, so that the risk of installation errors can be avoided. It is also possible to use the cost-effective TIG welding process.

A further advantageous embodiment provides that the welding area is formed bent over at the terminal connection, so that a surface for connecting the parts is formed. The size is optimized after the necessary current transition and the lowest electrical resistance. A welded joint can be implemented here, as well as a solder joint.

It is also advantageously provided that the items of magnetic sheet and terminal connection can be treated as bulk material. These can - but do not have to - be positively connected with each other. Due to the external shape and coordination of the tolerances, the parts can be placed inside each other and inserted conclusively into the bobbin, so that the magnetic sheet is pressed directly to the pole face from below. A firm connection of the two parts is costly, by the custom-fit installation or by the exact fit impressions in the mold cavity of the bobbin this is bypassed.

The short-circuit release according to the invention, in particular for a circuit breaker, has an armature and a pole, which are arranged inside a coil former. On the spool a coil is wound. The bobbin is framed by a yoke plate and a terminal connection. The yoke plate is preferably U-shaped. The terminal connection surrounds the bobbin including coil preferably with two right-angled legs. At the two legs of the terminal terminal, a magnetic plate is arranged, which is preferably U-shaped and has two legs, and a transition region. In this case, the transition region of the magnetic sheet bears against a first limb of the terminal connection. The one leg of the magnetic plate abuts against a second leg of the terminal connection. The other leg of the magnetic plate is anchored in the bobbin. The coil has two ends. One end of the coil is connected to the overload protection. The other end of the coil is welded to the terminal connection. Below the one leg of the terminal terminal, a plunger is arranged, which is guided in a contact slide device of the circuit breaker.

The inventive short-circuit release with optimized magnetic circuit has a good magnetic design with reduced electrical loss. There is a lower magnetic excitation needed, which is associated with a lower power loss. In addition, the space requirement is minimized by the fact that no platinierter starting material is used. The arrangement of the parts to each other is optimized. It is also advantageous that the items can be treated as bulk material. By means of the present short-shot release according to the invention, moreover, the dimensions and tolerances can be defined more precisely. The extended current path from the N-trigger to the terminals also causes the terminal temperature to drop. With the present short-circuit release according to the invention, a cost-effective solution for high switching capacities has been created in a circuit breaker.

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 einen erfindungsgemäßen Kurzschlussauslöser mit zusätzlichem Magnetblech;
• Fig. 2 in einer perspektivischen Darstellung einen Klemmenanschluss mit daran angeordnetem Magnetblech;
• Fig. 3 in einer Schnittdarstellung den Spulenkörper mit Anker und Joch und der Anordnung zwischen der Polfläche und dem Magnetblech;
• Fig. 4 in einer perspektivischen Darstellung die Verbindung zwischen einem Spulenende und dem Klemmenanschluss;
• Fig. 5 in einer perspektivischen Darstellung der Spulenanschluss nach Fig. 4 mit einer Aussparung am Klemmenanschluss;
• Fig. 6 in einer perspektivischen Darstellung ein weiteres Ausführungsbeispiel eines Spulenanschlusses mit umgebogenem Schweißbereich am Klemmenanschluss.

Here are shown schematically:

• Fig. 1 in a perspective view of a short-circuit release according to the invention with additional magnetic sheet;
• Fig. 2 in a perspective view of a terminal connection with arranged thereon magnetic sheet;
• Fig. 3 in a sectional view of the bobbin with armature and yoke and the arrangement between the pole face and the magnetic plate;
• Fig. 4 in a perspective view of the connection between a coil end and the terminal connection;
• Fig. 5 in a perspective view of the coil connection after Fig. 4 with a recess at the terminal connection;
• Fig. 6 in a perspective view of another embodiment of a coil terminal with bent welding area at the terminal connection.

In Fig. 1 is an inventive short-circuit release 1, in particular for a circuit breaker shown having an armature 2 and a pole 3, which are arranged within a bobbin 4. On the bobbin 4, a coil 5 is wound. The bobbin 4 is framed by a yoke 6 and a terminal connection 7. The yoke 6 is preferably U-shaped. The terminal connection 7 surrounds the bobbin 4, including the coil 5, preferably with two legs 8, 9 which are at right angles to one another. At the two legs 8,9 of the terminal terminal 7, a magnetic plate 10 is arranged, which is preferably U-shaped and has two legs 11, 12, and a transition region 13. In this case, the transition region 13 of the magnetic sheet 10 is located on the leg 8 of the terminal terminal 7. The leg 12 of the magnetic sheet 10 abuts the leg 9 of the terminal terminal 7. The leg 11 of Magnetic plate 10 is anchored in the bobbin 4. The coil 5 has two ends 14, 15. The end 14 of the coil is connected to the overload protection (not shown). The end 15 of the coil 5 is welded to the terminal connection 7. Below the leg 9 of the terminal terminal 7, a plunger 16 is arranged, which is guided in a contact slide device of the line switch (not shown).

Fig. 2 shows the terminal connection 7 with magnetic plate 10 arranged thereon. The magnetic plate 10 is arranged on the legs 8, 9 of the terminal connection 7. In this case, the transition region 13 of the magnetic sheet 10 is located on the leg 8 of the terminal connection 7. The leg 12 of the magnetic sheet 10 abuts the leg 9 of the terminal terminal 7. In the magnetic sheet 10, a recess 17 or embossing, axially parallel to the axial center of the short-circuit release arranged in order to allow the required space for the adjacent coil. Here, the required cross section can vary as far as required by the design of the coil. This also allows to optimize the installation space in the overall device and to provide manufacturing tolerances available. A corresponding free space in the terminal connection is a prerequisite for the implementation of the embossing on the magnetic sheet 10th

Fig. 3 shows the bobbin 4 with armature 2 and pole 3 and the arrangement between the pole face 18 and the magnetic plate 10. The items of the magnetic plate and terminal connection can be treated as bulk material. These can, but do not have to be connected in a form-fitting way. Due to the external shape and coordination of tolerances, the parts can be placed inside each other and inserted in a conclusive manner in the bobbin, so that the magnetic sheet is pressed directly to the pole face 18 from below. A firm connection of the parts is costly, by the accurate installation or by the exact fit impressions in the mold cavity of the bobbin 4, this is bypassed.

In Fig. 4 the connection between the coil end 15 and the terminal connection 7 is shown. For this purpose, a recess 19 is formed on the magnetic sheet 10, so that the coil end 15 can be welded to the terminal connection 7.

Fig. 5 indicates the coil connection Fig. 4 at the terminal connection 7, wherein an additional recess 20 is shown on the terminal connection 7. By the recess 20 or recess at the terminal connection 7 supernatants are compensated by welding beads, so that the risk of installation errors is reduced and the less expensive TIG welding process can be used.

In Fig. 6 a further embodiment of a coil terminal is shown with bent welding area 21 at the terminal connection 7. Here, the welding area 21 is bent at the terminal connection 7, so that a surface 22 for connecting the parts is formed. The size is optimized after the necessary current transition and the lowest electrical resistance. A welded joint can be implemented, as well as a solder joint is possible.

The inventive short-circuit release with optimized magnetic circuit has a good magnetic design with reduced electrical loss. There is a lower magnetic excitation needed, which is associated with a lower power loss. In addition, the space requirement is minimized by the fact that no platinierter starting material is used. The arrangement of the parts to each other is optimized. It is also advantageous that the items can be treated as bulk material. By means of the present short-shot release according to the invention, moreover, the dimensions and tolerances can be defined more precisely. The extended current path from the N-trigger to the terminals also causes the terminal temperature to drop. With the present short-circuit release according to the invention, a cost-effective solution for high switching capacities has been created in a circuit breaker.

Claims (7)

1. Short-circuit release (1) having an armature (2) and pole (3) that are located inside a coil former (4) and further having a yoke plate (6) and terminal connection (7) that are positioned around the coil former (4), characterised in that arranged opposite the yoke plate (6) is a magnetic plate (10) resting against the terminal connection (7), wherein a recess (19) is embodied on magnetic plate (10) in such a way as to enable a coil (5) wound onto the coil former (4) to be welded directly onto the terminal connection (7).
2. Short-circuit release (1) according to claim 1, characterised in that the magnetic plate (10) and terminal connection (7) are mutually arranged in a form-fit manner.
3. Short-circuit release (1) according to claim 1 or 2, characterised in that a depression (17) has been provided in the magnetic plate (10).
4. Short-circuit release (1) according to claim 3, characterised in that the depression (17) in the magnetic plate (10) is arranged axially parallel to the middle of the axis of the short-circuit release (1).
5. Short-circuit release (1) according to claim 3 or 4, characterised in that a recess is embodied in terminal connection (7) corresponding to the depression (17) in the magnetic plate (10).
6. Short-circuit release (1) according to claim 1, characterised in that the terminal connection (7) has a recess (20) in the region of the coil-terminal weld.
7. Short-circuit release (1) according to claim 1, characterised in that a welding region (21) that is bent round is embodied on the terminal connection (7) so as to provide an area (22) for the weld joint between the coil (5) and terminal connection (7).

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