EP2927927B1 - Dc contactor with additional switching for ac loads and polling contrary to the preferred power direction - Google Patents

Description

The present invention relates to a direct contact DC contactor according to the preamble of independent claim 1. Such a DC contactor has a double break with two contact points each comprising a fixed contact and a movable contact. The movable contacts are arranged on a contact bridge. Furthermore, the generic DC contactor to an arc quenching device and a blowing device, wherein the blowing device is adapted to blow a switching arc, which arises at the first contact point when opening the contact points when switching in the preferred direction of flow in the arc quenching device. Further, in the generic DC contactor adjacent to the movable contact of the first contact point, a commutating plate is disposed, wherein the contact bridge and the commutating are electrically isolated from each other, and wherein the commutation is electrically connected to the fixed contact of the second contact point, so that the resulting at the first contact point Switching arc when switching in the preferred direction of current skips due to the effect of the blowing device of the contact bridge on the commutation and thereby the resulting at the second contact point switching arc is bridged.

A generic DC contactor is for example off DE 10 2010 031 907 B9 known. The contactor is very simple and is used, for example, in railway applications to switch DC up to about 3 kV nominal voltage. Since in the generic contactor of the second switching arc is bridged at the second contact point when skipping the first switching arc of the contact bridge on the commutation, the second switching arc is simply brought to extinction. It remains only the first switching arc stand, which in turn is blown by the blowing device in the arc quenching device and extinguished there.

Out EP 2463876 A1 a switching device with two contact points is known, each contact point are each associated with a quenching chamber and an auxiliary quenching chamber.

In the railway industry, some high demands are placed on DC contactors. In this area, it sometimes happens that reversible or AC switching loads must be switched, the reversible or AC switching loads to be switched, however, are generally much lower than the rated switching load in DC operation in the preferred direction of current. Particularly low such loads can be switched with a generic DC contactor. However, the demands placed on the contactors used in the field of railway technology are becoming increasingly greater. There is therefore a need for DC contactors with improved switching capability for AC loads and polarity against the preferred direction.

Object of the present invention is therefore to provide a DC contactor of the generic type with improved switching capability for AC loads and polarity against the preferred direction.

The object is achieved by the features of independent claim 1. Accordingly, then a solution according to the invention is the task before when the DC contactor has a Hilfsbogenbogenlöscheinrichtung, which is arranged between two contact rails which connect the two fixed contacts with terminals of the DC contactor, wherein the blowing device such is dimensioned and designed that the resulting at the first contact switching arc is skipped when switching against the preferred direction of flow due to the action of the blowing of the contact bridge on the fixed contact of the second contact point and is blown between the two fixed contacts through the auxiliary arc quenching device.

The invention provides a very simple solution to significantly improve the switching capability of the generic DC contactor for AC loads and polarity against the preferred direction. The DC contactor according to the invention is furthermore extremely simple in design and can therefore be manufactured easily and inexpensively. By virtue of the solution according to the invention, the auxiliary arc quenching device can be accommodated in a particularly space-saving manner in the DC contactor, resulting in an overall compact design of the DC contactor according to the invention.

The main arc quenching device of the DC contactor according to the invention, referred to below as an arc quenching device, comes only when switching in Preferred direction for use. It is preferably arranged adjacent to the first contact point. The resulting at the first contact switching arc then only has to cover a small way to the arc quenching device and is therefore quickly brought to extinction. Further preferably, the contact bridge and the Kommutierblech are separated by an air gap. Further preferably, the commutation plate is designed as an arc guide plate and surrounds an edge region of the arc quenching device at least partially. One of the arc root points of the resulting at the first contact point switching arc is performed in this embodiment on the arc guide along the arc quenching device. As a result, the switching arc is stretched and blown into the arc quenching device.

Advantageous embodiments of the present invention are the subject of the dependent claims.

Preferably, the two contact rails take on the task of directing the switching arc in the auxiliary arc quenching device, and are therefore each designed as an arc guide plate. Further preferably, the contact rail connected to the fixed contact of the first contact point simultaneously forms the second arc guide plate for the arc quenching device and the first arc guide plate for the auxiliary arc quenching device. The contact rail connected to the fixed contact of the second contact point preferably forms the second arc guide plate for the auxiliary arc quenching device.

In a further preferred embodiment of the present invention, the auxiliary arc quenching device is dimensioned smaller than the arc quenching device. Since the DC contactor usually only in exceptional cases must have a switching capability for AC loads and polarity against the preferred direction, and the loads to be switched are usually less than the rated switching load of the DC contactor, this results in a particularly compact design. More preferably, the auxiliary arc quenching device has fewer quenching elements than the arc quenching device.

In a further preferred embodiment of the present invention, the arc quenching device and / or the auxiliary arc quenching device comprise a plurality of ceramic quenching elements. Ceramic extinguishing elements have opted for the deletion of Switching arcs proven. Further preferably, at least some of the extinguishing elements of the arc quenching device are combined to form an externally removable insert, to facilitate accessibility to the first contact point for maintenance and inspection purposes. It is particularly advantageous if the insert is mechanically locked or unlocked.

In a further preferred embodiment of the present invention, flow channels are formed between the extinguishing elements, the flow channels each having a scattering section, wherein the scattering sections adjacent flow channels are formed differently inclined, so that a fanning of the exiting from the extinguishing elements gases is achieved. This embodiment has the advantage that a plasma generated by the switching arc can be removed particularly quickly. As a result, the switching arc is extinguished very quickly.

In a further preferred embodiment of the present invention, the contact bridge is tapered at an end facing the commutation plate. Preferably, the contact bridge is tapered at this end. This ensures that the switching arc jumps in the preferred direction of current quickly and reliably on the commutation.

In a further preferred embodiment of the present invention, the blowing device has a permanent magnet, which is arranged adjacent to one end of the contact bridge, wherein a ceramic protective element is arranged between the permanent magnet and the end of the contact bridge. As a result, the permanent magnet is protected from damage by the switching arc. Preferably, the protective element is plate-shaped. Further preferably, the permanent magnet is arranged at that end of the contact bridge, which faces the Kommutierblech.

In a further embodiment of the present invention, the commutation plate is at least partially covered on a side facing away from the arc quenching device by a shielding. As a result, further electrical or electronic components of the DC contactor can be arranged in the region of the outer side of the commutation plate, without causing any disturbing effects or damage due to the switching arc. The electrical or electronic components may be part of the control of the DC contactor, for example, or it may be an auxiliary switch.

In a further preferred embodiment of the present invention, the contact points and the commutation are insulated by an insulating film at least partially against a drive and / or a control of the DC contactor. As a result, taking into account the required clearance and creepage distances a more compact design can be achieved. In order to avoid erosion of the insulating film in the region of the second contact point, a protective covering is preferably arranged between the insulating film and the second contact point. Preferably, this is plate-shaped and made of steel.

• Fig. 1 eine Schrägansicht eines erfindungsgemäßen Gleichstromschützes,
• Fig. 2 das erfindungsgemäße Gleichstromschütz aus Fig. 1 mit teilweise geöffnetem Gehäuse, und
• Fig. 3 eine Detailansicht eines der Löschelemente des erfindungsgemäßen Gleichstromschützes aus den Figuren 1 und 2.

An advantageous embodiment of the present invention will be explained in more detail below with reference to drawings. Show it:

• Fig. 1 an oblique view of a DC contactor according to the invention,
• Fig. 2 the DC contactor according to the invention Fig. 1 with partially open housing, and
• Fig. 3 a detailed view of one of the extinguishing elements of the DC contactor according to the invention from the FIGS. 1 and 2 ,

For the following statements applies that the same parts are designated by the same reference numerals. If reference signs are contained in a drawing, which are not discussed in detail in the associated description of the figures, reference is made to preceding or subsequent description of the figures.

An oblique view of a DC contactor 1 according to the invention is shown in FIG Fig. 1 shown. The inner structure of the DC contactor 1 is in Fig. 2 shown. The DC contactor 1 has a double break with two contact points 2 and 3. The first contact point consists of the fixed contact 4 and the movable contact 5, the second contact point 3 comprises the fixed contact 6 and the associated movable contact 7. The two movable contacts 5 and 7 are arranged on a contact bridge 8. The contact bridge 8 is actuated by an electromagnetic drive 25, which is controlled by the controller 23. The controller 23 is arranged outside the housing 31 of the DC contactor 1 according to the invention and therefore also in Fig. 1 to recognize. Each of the two fixed contacts 4 and 6 is connected via a contact rail 14 or 15 with a corresponding terminal contact 27 of the DC contactor. When opening the contact points creates a switching arc, which must be brought to extinction as quickly as possible in order to avoid damage to the contacts or other components of the DC contactor. For this purpose, the DC contactor 1 is equipped with an arc quenching device 9 and a blowing device 10, which consists essentially of a permanent magnet. The magnetic field of the permanent magnet 10 is aligned such that a switching arc emerging at the first contact point 2 in the preferred current direction is driven into the arc quenching device 9. In order to ensure that the magnetic field is built up at the critical points, corresponding pole plates 30 known from the prior art are arranged on both sides of the housing. One of the two pole plates is in Fig. 1 shown.

The DC contactor 1 according to the invention has a so-called commutation plate 11, which starts near the first contact point 2 and engages in the left edge region of the arc quenching device 9 like a clamp. The Kommutierblech 11 is electrically connected via a Verbindungslitze 12 with the fixed contact 6 of the second contact point. In the preferred direction of the resulting switching arc at the first contact point jumps due to the effect of the magnetic field from the contact bridge 8 on the commutation plate 11 and thereby bridges the resulting at the second contact point switching arc. The Kommutierblech 11 and connected to the first fixed contact 4 contact rail 14 then act as Lichtbogenleitbleche. Through it, the resulting at the first contact point 2 switching arc is stretched while it is blown by the permanent magnet 10 in the arc quenching device 9. As a result, a fast and safe deletion of the switching arc is achieved.

In order to favor the skipping of the switching arc of the contact bridge 8 on the Kommutierblech 11, which is located at the contact point 2 end 20 of the contact bridge 8 is formed tapering. In order to prevent the switching arc from penetrating from the contact bridge 8 to the adjacently arranged permanent magnet 10, a plate-shaped ceramic protective element 21 is arranged between the end 20 of the contact bridge 8 and the permanent magnet 10.

If a voltage polarized opposite to the preferred direction is applied to the fixed contacts of the DC contactor according to the invention, then it can be at the first contact point 2 resulting switching arc can not be deleted by the arc quenching device 9. The magnetic field of the permanent magnet 10 ensures in this case that the resulting at the first contact point 2 switching arc is blown away from the arc quenching device 9 down. In order to ensure reliable deletion of the switching arc in this case too, the DC contactor according to the invention is equipped with an auxiliary arc quenching device 13. This is located between the two contact rails 14 and 15 of the two fixed contacts 4 and 6. The resulting at the first contact point 2 switching arc is due to the action of the magnetic field along the contact bridge 8 from the movable contact 5 of the first contact point in the direction of the movable contact 7 of the second Pad driven and jumps over on the adjacent fixed contact 6 of the second contact point or merges with the resulting at the second contact point 3 switching arc. In any case, the switching arc produced at the second contact point 3 is extinguished as soon as the switching arc arising at the first contact point jumps from the contact bridge 8 to the fixed contact 6 of the second contact point 3. From this point on, the two contact rails 14 and 15 act as arc guide plates. The switching arc is driven by the blowing action of the permanent magnet 10 along these two Lichtbogenleitbleche in the auxiliary arc quenching device 13 and extinguished there. The DC contactor according to the invention is therefore also suitable for switching off currents against the preferred direction or AC loads to a certain degree safely and reliably. In order to achieve a compact design, the contact points and the commutation are insulated by an insulating film 24 to drive and control. In order to avoid erosion of the insulating film in the region of the second contact point 3, caused by the switching arc generated at the contact point 3, the insulating film 24 is covered in this area by a protective covering in the form of a small steel plate 26. In order to protect the controller 23 from interference, a shielding element 22 is arranged between the controller 23 and the commutation plate 11 or the arc quenching device 9.

Both the arc quenching device 9 and the auxiliary arc quenching device 13 consist of several ceramic quenching elements 16. One of the quenching elements is shown in detail in FIG Fig. 3 shown. How out Fig. 3 becomes clear, in each case between two adjacent extinguishing elements, a flow channel 17 is formed through which the through the Switching arc generated plasma is led to the outside. Towards the outlet end 19, the flow channel has a scattering section 18, the scattering sections of adjacent flow channels being differently inclined, so that a fanning out of the gases emerging from the extinguishing elements is achieved. As a result, the plasma generated by the switching arc can be transported away faster, whereby the switching arc can be deleted faster.

For maintenance and inspection purposes, some of the extinguishing elements of the arc quenching device 9 can be removed without having to disassemble the housing 31 of the DC contactor according to the invention for this purpose. The removable extinguishing elements are by means of in the FIGS. 1 and 2 shown staples 28 summarized to a removable insert. This can be done by means of in Fig. 1 bolt shown 29 are locked or unlocked. The insert in this case comprises those extinguishing elements by which the first contact point 2 is covered. By removing the insert, the contacts can be checked accordingly.

Claims (9)

1. A direct-current contactor (1) with preferential current direction, comprising a double break with two contact points (2, 3), which each comprise a fixed contact (4, 6) and a movable contact (5, 7), the movable contacts (5, 7) being arranged on a contact bridge (8), and further comprising an electric arc extinguishing device (9) as well as a blowing device (10, 30), said blowing device (10, 30) being configured to blow a switch arc, which forms at the first contact point (2) when the contact points (2, 3) are being opened, into the electric arc extinguishing device (9), when switching takes place in the preferential current direction, wherein a commutating plate (11) is arranged adjacent the movable contact (5) of the first contact point (2), wherein the contact bridge (8) and the commutating plate (11) are electrically insulated from one another, and wherein the commutating plate (11) is potentially connected to the fixed contact (6) of the second contact point (3), so that, when switching takes place in the preferential current direction, the switch arc forming at the first contact point (2) jumps from the contact bridge (8) to the commutating plate (11) due to the effect produced by the blowing device (10), thus bridging the switch arc formed at the second contact point (3), characterized in that the direct-current contactor (1) comprises an auxiliary electric arc extinguishing device (13) arranged between two contact rails (14, 15), which connect the two fixed contacts (4, 6) to connecting contacts (27) of the direct-current contactor (1), the blowing device (10, 30) being dimensioned and configured such that, due to the effect produced by the blowing device (10, 30), the switch arc forming at the first contact point (2) jumps, when switching takes place in a direction opposite to the preferential current direction, from the contact bridge (8) to the fixed contact (6) of the second contact point (3) and is caused to pass between the two fixed contacts (4, 6) and into the auxiliary electric arc extinguishing device (13) by means of blowing.
2. The direct-current contactor (1) according to claim 1, characterized in that the auxiliary electric arc extinguishing device (13) is dimensioned such that it is smaller than the electric arc extinguishing device (9).
3. The direct-current contactor (1) according to one of the claims 1 to 2, characterized in that the electric arc extinguishing device (9) and/or the auxiliary electric arc extinguishing device (13) comprise a plurality of extinguishing elements (16) made of ceramics.
4. The direct-current contactor (1) according to claim 3, characterized in that flow passages (17) are formed between the extinguishing elements (16), said flow passages (17) being each provided with a dispersing portion (18), the dispersing portions (18) of neighboring flow passages (17) being configured such that they have different inclinations, so that the gases discharged from the extinguishing elements will be fanned out.
5. The direct-current contactor (1) according to one of the claims 1 to 4, characterized in that the contact bridge (8) narrows at an end (20) facing the commutating plate (11).
6. The direct-current contactor (1) according to one of the claims 1 to 5, characterized in that the blowing device (10, 30) includes a permanent magnet (10) disposed adjacent to an end (20) of the contact bridge (8), a ceramic protection element (21) being arranged between the permanent magnet (10) and the end (20) of the contact bridge (8).
7. The direct-current contactor (1) according to one of the claims 1 to 6, characterized in that the commutating plate (11) is covered, at least partially, by a shield element (22) on an outer side facing away from the electric arc extinguishing device (9).
8. The direct-current contactor (1) according to one of the claims 1 to 7, characterized in that the contact points (2, 3) and the commutating plate (11) are insulated, at least in certain areas thereof, from a drive (25) and/or a control unit (23) of the direct-current contactor (1) by means of an insulating foil (24).
9. The direct-current contactor (1) according to claim 8, characterized in that a protective cover (26) is arranged between the insulating foil (24) and the second contact point (3).

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