EP2737506B1 - Switch for direct current operation - Google Patents

Description

The invention relates to a contactor for DC operation, comprising a first and a second contact, which are formed as fixed contacts, and a third and a fourth contact, which are arranged on a contact bridge. Furthermore, the contactor comprises a guide, by means of which the contact bridge is movably mounted along a direction of movement, and a magnet arrangement for generating electromagnetic force on electric arcs. The first and third contact and the second and fourth Kantakt respectively form pairs of contacts between which contact contact is made when the contact bridge is in a closed position.

In particular, when opening the contacts may cause an electric arc, so a spark with gas discharge. The occurrence of arcing during the switching process has a negative impact on the contactor. The electric arc maintains the flow of current between the contacts even after the physical separation of the respective contact surfaces, thereby increasing the switching time. The electrical discharge in the arc also releases a relatively high amount of heat, causing unwanted heating takes place in the contactor. In particular, the heating leads to a high degree of wear ("burning off") of the contacts if the arc remains at the location of the contacts for a long time. This eventually leads to a reduction in the lifetime of the contactor. In contactors with so-called double interruption, an arc generally occurs at each of the two contact pairs.

In order to solve the above-described problem, DC motors and arc quenching apparatuses are usually used for DC applications. The permanent magnets are arranged in the vicinity of the contact pairs. They each generate a magnetic field, which generates a force on the respective arc at a suitable polarity, which is usually referred to as "magnetic blast". The arcs are driven by this force in the direction of arranged next to the contact pairs arc extinguishing devices such as extinguishing chambers.

For unidirectional operation, the permanent magnets may have the same polarity. In this arrangement, both arcs are driven with proper use each in one of the extinguishing chambers. However, if the contactor is connected with incorrect polarity, both arcs will not be moved into the quenching chambers due to the effect of the blast fields, but in the opposite direction, which may cause them to remain in one place for too long, thus causing the negative effects described above.

If the contactor is to be operated bidirectionally, the permanent magnets usually have a mutually opposing polarity. The two arcs are thus moved in the same direction due to the oppositely directed current flow. As a result, regardless of the polarity, one arc is always driven in the direction of the quenching chamber and the other is driven away from the quenching chamber. Therefore, appropriate measures must be taken to prevent the negative effects caused by one of the arcs.

In the DE 10 2006 035 844 B4 describes a contactor for DC and AC operation, which in addition to the two permanent magnets with opposite polarity comprises two puff coils. The puff coils are activated only when one of the arcs, driven by the magnetic field of one of the permanent magnets, jumps over a suitably arranged arc guide plate. Due to the effect of the coil magnetic field, the arc is then directed in the direction of a quenching device. The disadvantage here is the increased space required for the additional extinguishing device in the contactor, the heating by the current flow in the coil and not least the increased by the use of additional coils manufacturing cost of the contactor.

From the DE 102 12 948 B4 is a contactor for AC and DC operation is known in which the contact bridge on the side remote from the blowing direction has a transverse to the blowing direction, sharp-edged groove. Will an arc of the Flushing chamber driven away, so the formation of the groove prevents further movement of the arc, which hangs on the edge of the groove. In a reversal of the direction of current flow in AC operation, the arc is finally driven into a quenching chamber: The disadvantage here, however, that remains in DC operation of the arc in the case described above for a relatively long time in the central region of the contact bridge.

document EP 0 473 013 A2 discloses a DC contactor according to the preamble of claim 1.

The present invention is therefore based on the object to provide an improved contactor for bidirectional DC operation.

The object is achieved by the features of claim 1. Accordingly, the contactor according to the invention is characterized in that the movable contact bridge has at least one recess which is arranged between the guide and the third contact, wherein the at least one recess is formed such that an opening is provided on the contact bridge; through which an arc produced at the third contact can occur in the direction of the direction of movement of the contact bridge. Through this opening arcs can escape, which are blown by the magnetic field for guidance.

Also, between the guide and the fourth contact, a corresponding recess may be arranged. This further recess can be identical in terms of their design and their spatial arrangement to the recess between the guide and third contact. The following comments on the last-mentioned recess therefore also refer to the recess between the guide and the fourth contact.

The contactor according to the invention further comprises in a preferred embodiment in each case a contact pair associated permanent magnets and arc quenching devices. The two magnets are preferably oppositely poled. Arcing when opening the contacts arcs, so regardless of the current direction in the contactor always one of the arcs is driven by the magnetic field of one of the magnets in the direction of the associated extinguishing device. The other arc, however, moves towards the leadership of the contact bridge. However, the recess prevents the arc from damaging the guide wreaks. Rather, the arc is guided by suitable Umleitbleche through the recess and away from the contacts. In this way, damage to the materials in the region of the contacts and the leadership of the contact bridge can be prevented.

Preferably, at least one of the permanent magnets is provided with a pair of pole plates, which at least partially surround the contact pair, which is associated with the permanent magnet, laterally. The pole plates provide a relatively homogeneous magnetic field in the area of the contacts, which further strengthens the force on the arcs. Again, that the other permanent magnet can be equipped with pole plates accordingly.

In a preferred embodiment, the contact bridge comprises a substantially strip-shaped basic body with an upper side, a lower side, two longitudinal sides and two narrow sides. The contact bridge can be made of a metal strip.

According to a preferred embodiment, the at least one recess in the contact bridge is formed in the form of an indentation, which is open to one of the longitudinal sides of the contact bridge. In this case, the indentation is understood as a spatial area that is accessible both from the top side, the underside, as well as from one of the longitudinal sides of the contact bridge.

According to one embodiment, the contact bridge has said two recesses each in the form of indentations, wherein the recesses may be open to the same longitudinal side of the contact bridge or opposite longitudinal sides of the contact bridge. The at least one recess in the contact bridge may be L-shaped.

The contact bridge preferably has an extension on at least one of its narrow sides, which has an angle to the main body of the contact bridge. Correspondingly, another extension can also be formed on the other narrow side, which can be identical or approximately identical to the first-mentioned extension in terms of shape and arrangement.

The extension extends substantially away from the fixed contacts and can serve to guide the arcs in the direction of suitable extinguishing devices. The extension preferably extends substantially perpendicular to the main body of the contact bridge. The extension and the base are at an angle of 90 °. However, the extension can also be designed such that it extends substantially parallel to the main body. Extension and body form two mutually spaced U-legs. The angle at U-shaped arrangement of the extension is then 180 °. Depending on the contactor, the angle can also assume values of 90 ° to 180 °, for example 120 or 150 °.

In the region of the recess, the cross-section of the contact bridge is reduced. In order to reduce the thereby increased electrical resistance in this area, the contact bridge there preferably has a widening or a widening section. The widenings may be formed for example as additional bends, which are integrally formed on one of the longitudinal sides of the base body.

Between the guide of the contact bridge and the third contact, a first deflecting plate may be arranged, which at least partially engages in the at least one recess of the contact bridge. The contactor may have a further, second deflecting plate, which engages in the other recess of the contact bridge. In this case, the first deflecting plate is arranged between the guide of the contact bridge and the third contact, while the second deflecting plate is arranged between the guide of the contact bridge and the fourth contact. With a suitable polarity of the magnet arrangement, one of the arcs can thus be conducted away from the contact assigned to this deflecting plate via one of the deflecting plates. The baffles may be formed integrally with the fixed contacts.

According to a further preferred embodiment, the first deflecting plate comprises an angled section. In this case, the angled section preferably forms a substantially right angle with the remaining part of the deflecting plate.

Preferably, the contactor according to the invention comprises a first partition, which is arranged between the guide of the contact bridge and the third contact, preferably between the guide of the contact bridge and the first baffle. The first partition at least partially engages in the at least one recess of the contact bridge. It is made of an insulating material such as ceramic or plastic and serves as an additional protection against the damage caused by an arc. The contactor may have a further, second partition which is arranged between the guide of the contact bridge and the fourth contact and engages in the other recess of the contact bridge.

A further preferred embodiment of the invention provides that a respective quenching chamber is arranged adjacent to the contact pairs. At least one of the arcs can be directed by the magnetic field of one of the permanent magnets in a suitable polarity in one of the extinguishing chambers. For this purpose, arc guide plates are arranged between each of the pairs of contacts and the extinguishing chamber arranged adjacent thereto. The arc guide plates are designed such that the distance between baffles leading to the same quenching chamber, increases in the direction of this quenching chamber.

Figur 1

eine perspektivische Teilansicht eines erfindungsgemäßen Schützes in geöffneter Stellung der Kontakte zeigt;

Figur 2a

eine Seitenansicht des Schützes der Figur 1 im Längsschnitt zeigt;

Figur 2b

eine weitere Seitenansicht des Schützes der Figur 1 im Längsschnitt zeigt;

Figur 3

eine perspektivische Ansicht einer Kontaktbrücke zeigt;

Figur 4

eine Draufsicht der Kontaktbrücke der Figur 3 zeigt; und

Figur 5

eine perspektivische Teilansicht einer Magnetanordnung zeigt.

The invention will be further described in conjunction with the accompanying drawings, wherein

FIG. 1

shows a partial perspective view of a contactor according to the invention in the open position of the contacts;

FIG. 2a

a side view of the contactor of FIG. 1 in longitudinal section shows;

FIG. 2b

another side view of the contactor of FIG. 1 in longitudinal section shows;

FIG. 3

shows a perspective view of a contact bridge;

FIG. 4

a plan view of the contact bridge of FIG. 3 shows; and

FIG. 5

shows a partial perspective view of a magnet assembly.

In FIG. 1 is a partial perspective view of a contactor 1 according to the invention shown. The contactor 1 comprises a first contact 21 and a second contact 22, a third contact 31 and a fourth contact 32. The first contact 21 and the second contact 22 are formed as fixed contacts. The third contact 31 and the fourth contact 32 are arranged on a contact bridge 4. The contact bridge 4 is movably mounted on a guide 9. The contact bridge 4 can by the movable mounting between a closed position in which a contact contact between a first contact pair, consisting of the first contact 21 and the third contact 31, and a second contact pair consisting of the second contact 22 and the fourth contact 32nd , is given and moved to an open position. In the open position, no contact is made between the first contact 21 and the third contact 31 and the second contact 22 and the fourth contact 32. The contact bridge 4 is located in FIG. 1 in the open position.

Furthermore, the contactor 1 comprises a magnet arrangement, which consists of two permanent magnets 51, which are oppositely poled. The direction of the magnetic fields is indicated by the arrows 52.

The contact bridge 4 comprises two recesses 42, which are each arranged between one of the contacts 31, 32 and the guide 9 of the contact bridge (a detailed description of the contact bridge is later in the context of the description of the Figures 3 and 4 ). Furthermore, the contactor 1 comprises two deflecting plates 7, which are each arranged between one of the contacts 31, 32 and the guide 9 of the contact bridge. Each of the two baffles 7 engages in one of the recesses 42. Adjacent to the baffles 7 insulating on their side facing the guide 9 of the contact bridge 4 side partitions 71 are arranged, each of which partially engage in one of the recesses 42.

The contactor 1 further comprises two arc extinguishing chambers 81 and arc guide plates 82. The arc guide plates 82 are designed such that the distance between baffles 82, which lead to the same quenching chamber 81, increases in the direction of this quenching chamber. The magnetic fields of the permanent magnets 51 generate a force on each of the arcs formed when the contacts are opened. Due to the opposite polarity of the permanent magnets, one of the arcs is always directed away from the contacts, via the arc guide plates 82 into an arc extinguishing chamber 81, where it can be extinguished.

In FIG. 2a is a side view of the contactor 1 shown in longitudinal section. Regarding the individual components and peculiarities is therefore on the description too FIG. 1 pointed. The magnetic fields of the permanent magnets 51 generates a force on each of the arcs 8 formed when the contacts are opened. The arcs 8 are in FIG. 2a only shown in a schematic representation. The direction of force is in FIG. 2a sketched by a vector arrow based on the arc. Due to the opposite polarity of the permanent magnets, one of the arcs 8 is always directed away from the contacts, via the arc guide plates 82 into an arc extinguishing chamber 81, where it can be extinguished. The respective other arc 8, however, is driven in the direction of the guide 9 of the contact bridge 4.

FIG. 2b shows the contactor 1 according to FIG. 2a but at a later date. Due to the design of the arc guide plates 82, which widen in the direction of the quenching chamber 81, the arc 8 now in the vicinity of the quenching chamber 82 is also widened, which additionally contributes to its cooling. The other arc 8, however, is guided away from the third contact 31 through the recess 42 and via the deflecting plate 7. Optionally, 4 arc quenching plates can be arranged over the contact bridge, so that the deflected arc 8 can finally be driven between the quenching plates and deleted there.

FIG. 3 shows a perspective view of the contact bridge. 4 FIG. 4 shows the contact bridge in plan view. The contact bridge 4 has a substantially strip-shaped basic shape with a top 401, a bottom 402, two longitudinal sides 403 and two narrow sides 404. At the bottom of the contact bridge 4 are the third contact 31 and the fourth contact 32nd

In the middle contact bridge 4, two slots 45 and 46 are formed, which cooperate with the guide (not shown). Furthermore, the recess has an elevation 47, by means of which the position of one end of a spring 91 can be determined. The contact bridge 4 comprises the two recesses 42, in the form of Indentations are formed. The two recesses 42 are open to a longitudinal side 403 of the contact bridge 4. In addition, the two recesses 42 are viewed from above ( FIG. 4 ) L-shaped.

The recesses 42 are configured such that movement of an arc 8 (FIG. FIG. 2a . 2 B ) is interrupted along the contact bridge 4 on a direct path between one of the contacts 31, 32 and the elevation 47. If, for example, an arc 8 arises at the third contact 31, then it will first be activated by the action of the permanent magnets 51 (FIG. FIG. 1 ) are driven along the contact bridge 4 in the direction of the elevation 47. However, its movement in the direction of the elevation 47 is stopped at the recess 42 and the arc 8 can be deflected in the direction of movement of the contact bridge 4. In this way, the arc 8, the guide 9 ( FIG. 1 ) do not reach.

Furthermore, the contact bridge on its narrow sides 404 extensions 43. The extensions 43 extend substantially away from the third contact 31 and the fourth contact 32 and form a substantially right angle with the main body of the contact bridge 4. In the region of the recesses 42, the contact bridge 4 along one of the longitudinal sides 403 widening portions 44, which serve to increase the cross section of the contact bridge 4. Thus, despite the recesses 42, the contact bridge has sufficient cross-section to conduct current without much resistance between the contacts 31, 32 can.

FIG. 5 shows a schematic representation of a magnet arrangement of the contactor 1 according to the invention FIG. 1 and 2a-b with a permanent magnet 51 and two pole plates 53. The permanent magnet 51 and the pole plates 53 generate a magnetic field whose direction is indicated by the arrows 52. A contact pair, consisting of the first and the third contact or of the second and the fourth contact (not shown), is preferably arranged between the two pole plates 53.

List of reference numbers

1

contactor

21.22

first contact, second contact

31.32

third contact, fourth contact

4

Contact bridge

42

recess

43

Extension of the contact bridge

44

expansion section

45.46

slot

47

increase

401

Top of the contact bridge

402

Bottom of the contact bridge

403

Longitudinal side of the contact bridge

404

Narrow side of the contact bridge

5

magnet assembly

51

permanent magnet

52

Direction of the magnetic field

53

pole plate

7

Umleitblech

71

partition wall

8th

Arc with force vector

81

Arc chute

82

arc guide

83

Arc splitters

9

Guiding the contact bridge

91

feather

Claims (16)

1. Contactor for DC operation, comprising:

   - a first contact (21) and a second contact (22) that are formed as fixed contacts, and a third contact (31) and a fourth contact (32);

   - a contact bridge (4) which supports the third contact and the fourth contact (31, 32);

   - a guide (9) through which the contact bridge (4) is movably positioned in a direction of movement; and

   - a magnet arrangement (5) for generating electromagnetic force on electric arcs (8) which arise when the contacts (21, 22, 31, 32) are opened, contact being produced between a first contact pair, comprised of the first and third contact (21, 31), and between a second contact pair, comprised of the second and fourth contact (22, 32), in a closed position of the contact bridge (4), characterised in that the movable contact bridge (4) comprises at least one recess (42) which is arranged between the guide (9) and the third contact (31), the at least one recess (42) being configured such that an opening is provided in the contact bridge (4), through which opening an arc (8), arising at the third contact (31), can pass in the direction of movement of the contact bridge (4).
2. Contactor according to claim 1, characterised in that the magnet arrangement (5) comprises a first and a second permanent magnet (51), the first permanent magnet (51) being associated with the first contact pair and the second permanent magnet (51) being associated with the second contact pair, each permanent magnet (51) being arranged adjacent to the contact pair associated therewith and both permanent magnets (51) having opposite polarities.
3. Contactor according to claim 2, characterised in that at least one of the permanent magnets (51) is provided with a pair of pole plates (53), which laterally enclose the contact pair, with which the permanent magnet (51) is associated, at least in part.
4. Contactor according to any of claims 1 to 3, characterised in that the contact bridge (4) has a substantially strip-shaped base body having an upper side (401), a lower side (402), two longitudinal sides (403) and two narrow sides (404).
5. Contactor according to claim 4, characterised in that the at least one recess (42) is in the form of an indentation that is open towards one of the longitudinal sides (403) of the base body of the contact bridge (4).
6. Contactor according to claim 5, characterised in that the movable contact bridge (4) has two recesses (42) in the form of indentations, the indentations being open towards the same longitudinal side (403) or towards an opposite longitudinal side (403) of the contact bridge (4).
7. Contactor according to any of claims 4 to 6, characterised in that the movable contact bridge (4) has an extension (43) on at least one of the two narrow sides (404) thereof, which extension is at an angle to the base body.
8. Contactor according to claim 7, characterised in that the angle between the extension (43) and the base body is substantially 90°.
9. Contactor according to claim 7, characterised in that the angle between the extension (43) and the base body is substantially 180°.
10. Contactor according to any of claims 1 to 9, characterised in that in a region of the at least one recess (42), the contact bridge (4) has at least one expanded portion (44) for increasing the cross section of the contact bridge (4).
11. Contactor according to any of claims 1 to 10, characterised in that the at least one recess (42) in the contact bridge (4) is L-shaped.
12. Contactor according to claims 1 to 11, characterised in that a baffle plate (7) is arranged between the guide (9) of the contact bridge (4) and the third contact (31) and is engages in the at least one recess (42) of the contact bridge (4) at least in part.
13. Contactor according to claim 12, characterised in that the baffle plate (7) has a substantially right-angled portion.
14. Contactor according to claims 1 to 13, characterised in that an insulating partition (71) is arranged between the guide (9) of the contact bridge (4) and the third contact (31) and engages in the at least one recess (42) of the contact bridge (4) at least in part.
15. Contactor according to any of claims 1 to 14, characterised in that an arcing chamber (81) is arranged adjacent to each of the two contact pairs.
16. Contactor according to claim 15, characterised in that first arc baffles (82) are arranged between the first contact pair and the quenching chamber (81) adjacent thereto, and that second arc baffle plates (82) are arranged between the second contact pair and the quenching chamber (81) adjacent thereto, which arc baffle plates are each associated with one of the arcing chambers (82) and, with an appropriately polarised magnet arrangement (5), guide one of the two arcs (8) towards the arcing chamber (81) associated therewith, and in that the arc baffle plates (82) are designed such that the distance between the first and the second arc baffle plates (82) increases towards the arcing chambers (81) associated therewith.

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