Disconnecting device for interrupting a direct current of a current path as well as a circuit breaker

Abstract

A disconnecting device interrupts a direct current of a current path containing a hybrid switch which has a current-carrying mechanical contact system and a semiconductor switching system connected in parallel thereto. The contact system has a fixed contact and a moving contact. The moving contact is mounted on a contact bridge being coupled to a drive system moving the moving contact in a switching movement from an open position into a closed position resting against the fixed contact with a contact force. A first magnet element is mounted on the contact bridge and spaced apart from a stationary second magnet element by an air gap such that, when a current flows through the contact bridge, a magnetic field is produced in the first magnet element and the first and second magnet elements are magnetically attracted. The attraction produces a magnetic force directed in the same direction as the contact force.

Claims

1. A disconnecting device for interrupting a direct current of a current path, comprising: a hybrid switch having a current-carrying mechanical contact system and a semiconductor switching system connected in parallel with said current-carrying mechanical contact system, said current-carrying mechanical contact system having at least one stationary fixed contact, at least one moving contact, a current-carrying contact bridge, and a drive system; said at least one moving contact is mounted on said current-carrying contact bridge and is coupled to said drive system, which moves said at least one moving contact in a switching movement from an open position into a closed position resting against said at least one stationary fixed contact with a contact force; and said current-carrying mechanical contact system further having at least one first magnet element and a stationary second magnet element, said at least one first magnet element mounted on said current-carrying contact bridge, said at least one first magnet element being spaced apart from said stationary second magnet element by an air gap such that, when a current flows through said current-carrying contact bridge, a magnetic field is produced in said at least one first magnet element and said first and second magnet elements are magnetically attracted defining an attraction, said attraction producing a magnetic force directed in a same direction as the contact force.

2. The disconnecting device according to claim 1, wherein: said at least one stationary fixed contact is one of two fixed contacts; and said at least one moving contact is one of two moving contacts.

3. The disconnecting device according to claim 1, wherein said at least one first magnet element and said stationary second magnet element are each made of a soft magnetic material.

4. The disconnecting device according to claim 2, wherein: said current-carrying contact bridge is a vertical U-shaped member having free ends; and said two moving contacts are each disposed on one of said free ends of said vertical U-shaped member.

5. The disconnecting device according to claim 4, wherein: said at least one first magnet element is an anchor plate disposed along said vertical U-shaped member, and said stationary second magnet element is one of two second magnet elements implemented as magnet yokes, said two second magnet elements are disposed in an area of said fixed contacts, and each of said two second magnet elements have two vertical U-shaped members, which encompass a respective oppositely disposed said vertical U-shaped member of said current-carrying contact bridge, at least in sections.

6. The disconnecting device according to claim 4, wherein a switch movement of said current-carrying contact bridge is a swivel or rotational movement.

7. The disconnecting device according to claim 3, wherein said soft magnetic material is a soft magnetic ferrous material.

8. The disconnecting device according to claim 1, wherein the disconnecting device is a part of a circuit breaker.

9. A circuit breaker, comprising: a disconnecting device according to claim 1.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a schematic view of a current path with a direct current power source and with a consumer as well as with a circuit breaker switched in between;

(2) FIG. 2 is a perspective view of a mechanical contact system of the circuit breaker;

(3) FIG. 3 is a cross-sectional view of the contact system;

(4) FIG. 4 is a perspective view of the contact system;

(5) FIG. 5 is a side view of the contact system;

(6) FIG. 6 is a top view with sight of a lower side of the contact system;

(7) FIG. 7 is a perspective view of an alternative embodiment of the contact system in a closed position;

(8) FIG. 8 is a perspective view of the alternative embodiment of the contact system in an open position;

(9) FIG. 9 is a side view partially showing the contact system in the alternative embodiment;

(10) FIG. 10 is a cross-sectional view of a longitudinal section of the contact system; and

(11) FIG. 11 is a cross-sectional view of a transverse section of the contact system.

DETAILED DESCRIPTION OF THE INVENTION

(12) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:

(13) Parts and scales that correspond to one another are always referred to with the same reference signs in all figures.

(14) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a schematic and simplified representation of a current path 2 for carrying of a (direct) current I. The current path 2 has a direct current power supply 4 with a positive pole 4a and with a negative pole 4b, between which there is an operating voltage U. A load or consumer 6 is switched in the current path 2. A circuit breaker 8 is switched between the positive pole 4a and the load 6, for example, in the form of a hybrid power relay.

(15) The circuit breaker 8 is connected on the one side, by means of a power supply connection 10, to a power supply line that is located on the supply side and is thus current-carrying, and on the other side is connected, by means of a load connection 12, to the load-side current output line.

(16) The circuit breaker 8 has a series connection of a hybrid disconnecting device 14 and a breaker 15. The disconnecting device 14 is herewith configured with a hybrid switch 16, which has a mechanical contact system 18 and a series connection of a semiconductor switching system 20 and an (auxiliary) relay 21 connected in parallel. The semiconductor switching system 20 is represented in FIG. 1, as an example, by means of a controlled power semiconductor switch, in particular, by means of an insulated gate bipolar transistor (IGBT).

(17) The additional relay or disconnecting element 21 hereby ensures a galvanic disconnect of the current path 2 in the case of a triggering of the disconnecting device 14. The disconnecting device 14 is suitable and set up to securely carry the current I in the case of a residual or overload current until the breaker 15 trips. Secure carrying of the current I means, in particular, that the contacts of the mechanical contact system 18 are not interrupted or removed.

(18) In the following, a first embodiment of the contact system 18 is explained in more detail using FIG. 2 to FIG. 6.

(19) The contact system 18 shown in FIG. 2 has two stationary fixed contacts 22a, 22b, which are electrically conductively connected to the supply connection 10 on the one side and to the load connection 12 on the other side. The fixed contacts 22a, 22b are each conductively connected to an associated electrical connection 23a, 23b, by means of which the contact system 18 can be connected to current path 2.

(20) The contact system 18 also has two moving contacts 24a, 24b, which are carried by a common, current-carrying contact bridge 26. The contact bridge 26 is coupled with a drive system 28, by means of which the contact bridge 26 can be moved towards or away from the fixed contacts 22a, 22b.

(21) To switch the contact system 18, the contact bridge 26 can be moved from an open position to a closed position by means of the drive system 28 in the course of a switching movement. FIGS. 2 to 6 show the contact system 18 in the closed position, in which the moving contacts 24a, 24b at the respective contact points are in electrically conductive contact with the respective opposite fixed contacts 22a, 22b.

(22) In the embodiment example of FIGS. 2 to 6, the switching movement brought about by the drive system 28 when opening and closing the contact system 18 takes place linearly along a (operating) direction of the drive system 28 which is perpendicular to the contacts 22a, 22b, 24a, 24b.

(23) The elongated, straight, more or less plate-shaped contact bridge 26 is, for example, manufactured as a stamped copper part. The moving contacts 24a and 24b are arranged on the opposing end faces of the more or less rectangular contact bridge 26. The moving contacts 24a and 24b are arranged on the flat surface or lower side 30 of the contact bridge 26 facing the fixed contacts 22a and 22b. The drive system 28 is located on the opposing flat side or top surface 32 of contact bridge 26.

(24) FIG. 3 shows a cross-sectional view of a longitudinal section of the contact system 18 along the III-III line shown in FIG. 2. As can be seen in a comparatively clear manner in the cross-sectional view of FIG. 3, the drive system 28 has a spring-loaded plunger 34 for actuating or moving the contact bridge 26.

(25) The plunger 34 is surrounded at least in sections by a spring element 36 which is designed, for example, as a coil spring and which is also hereinafter referred to as a contact pressure spring. The contact pressure spring 36 is arranged in such a way that, in the closed position, there is at least a certain spring tension, the restoring force of which acts as contact force Fk or contact pressure on the contact bridge 26 and thus on the moving contacts 24a and 24b (FIG. 4). In other words, the moving contacts 24a and 24b are subjected to a contact pressure by means of the actuator system 28, which ensures a secure contact of the contacts 22a, 22b, 24a, 24b. The contact force Fk is oriented along the direction of actuation of the drive system, i.e. in the direction along which the linear switching movement of the contact system 18 takes place.

(26) A magnetic element 38 is arranged on the contact bridge 26. The magnetic element 38 is designed as a more or less horseshoe-shaped or U-shaped magnet yoke, the horizontal U-shaped member 38a of which is located at the top side 32 of the contact bridge 26. The U-shaped member 38a has a central, further unspecified, circular recess through which the plunger 34, at least in sections, is passed. The U-shaped member 38a is arranged transversely, i.e. substantially perpendicular to the contact bridge 26.

(27) A vertical U-shaped member 38b is formed onto the opposite end faces of the U-shaped member 38a. The U-shaped members 38b are oriented perpendicular to the U-shaped member 38a and the contact bridge 26, i.e. essentially parallel to the plunger 34. The U-shaped members 38b hereby encompass the contact bridge 26, so that the U-shaped members 38b, at their free ends, at least partially protrude from the lower side 30 of the contact bridge 26 axially, i.e. they protrude beyond the lower side 30. A second magnetic element 40 is arranged at a distance from the free ends of the U-shaped members 38b. The magnetic element 40, which is designed as a flat, more or less rectangular anchor plate, is arranged parallel to the U-shaped member 38a, i.e. transverse to the contact bridge 26.

(28) In the closed position shown in the figures, the free ends of the U-shaped members 38b are each kept at a distance from the anchor plate 40 by means of an air gap 42. The anchor plate 40 is stationary, i.e. arranged fixed to a housing of the disconnecting device 14 or of the circuit breaker 8. The magnet yoke 38 and the anchor plate 40 are each made of a soft magnetic material, in particular of a soft magnetic ferrous material.

(29) As can, in particular, be seen in FIG. 4 and FIG. 5, the U-shaped members 38b have a more or less funnel-shaped cross-sectional shape in the plane defined by the longitudinal directions of the U-shaped members 38b and the contact bridge 26. The U-shaped member 38b hereby has a truncated cone or trapezoid-shaped area, which is formed at the base on the U-shaped member 38a, and a more or less rectangular area, which is formed on the base side of the trapezoid-shaped area opposite the base. The rectangular area hereby forms the free end of the U-shaped member 38b. The U-shaped member 38b can have a circular recess 44, as shown in FIG. 4.

(30) As can be seen, in particular, in the top view with a view of the underside 30, shown in FIG. 6, the anchor plate 40 has a more or less hourglass-shaped, cross-sectional shape, i.e. dual-tapered to the center, in the plane spanned by the longitudinal directions of the contact bridge 26 and the U-shaped member 38a. The waisted or tapered section is located centrally along the respective long side and in the area of the fixed contacts 22a and 22b.

(31) As schematically shown by arrows in FIG. 4, the electrical current I is supplied into the contact bridge 26 via the fixed contact 22a and the moving contact 24a, and is discharged from the contact system 18 via the moving contact 24b and the fixed contact 22b. Due to magnetic effects, at each of the contact points formed by the contact pairs 22a, 24a and 22b, 24b, a constriction force Fe occurs which is oriented opposite to the contact force Fk.

(32) The contact force Fk, i.e. the spring strength of the contact pressure spring 36, is, in particular, dimensioned in such a way that in the case of a normal current, i.e. an electric current I with a current strength less than or equal to a normal or nominal value, the constriction force Fe is reliably compensated. This means that the contact force Fk at a normal current is always greater than the constriction force Fe, so that unwanted lifting of the moving contacts 24a, 24b from the fixed contacts 22a, 22b is reliably and simply prevented.

(33) The magnetic elements 38 and 40 hereby prevent the constriction force Fe from separating the contacts 22a, 22b, 24a, 24b from each other in the event of a residual or overload current where the current I exceeds the nominal value. In the event of such an overcurrent, the contact force Fk of the contact pressure spring 36 is not sufficient to reliably compensate for the increasingly large constriction force Fe.

(34) When a current flows through the contact bridge 26, the current I generates a magnetic field around the contact bridge 26. The magnetic field polarizes the soft magnetic yoke 38 and the soft magnetic anchor plate 40, whereby the magnetic flux density in the area of the magnetic elements 38, 40 is significantly increased compared to the surroundings. A magnetic circuit is thereby formed between the magnet yoke 38, the air gap 42 and the anchor plate 40.

(35) The spacing by means of the air gap 42 thus creates an attracting magnetic force Fm between the magnet yoke 38 and the anchor plate 40. Since the anchor plate 40 is arranged stationary or fixed in the housing in the circuit breaker 8, the magnet yoke 38 is pulled towards the anchor plate 40. The resulting magnetic force Fm is therefore in the same direction as the contact force Fk of the contact pressure spring 36, so that the magnetic force Fm and the contact force Fk add up to a resulting total force which counteracts the constriction force Fe. The contact pressure between the contacts 22a, 22b, 24a, 24b is thereby increased, which reliably and securely counteracts lifting of the contacts 22a, 22b, 24a, 24b, even in the event of a residual or overload current.

(36) The current-carrying contact bridge 26 thus generates a magnetic field supporting the drive system 28, the magnetic field being used to increase the contact pressure. When current flows through the contact bridge 26, the magnetic elements 38, 40 thus act as an additional electromagnetic actuator or solenoid, the magnetic force Fm of which acts through the U-shaped member 38a directly on the contact bridge 26 and thus on the moving contacts 24a, 24b.

(37) In the following, an alternative, second embodiment of the contact system 18′ is explained in more detail using FIG. 7 to FIG. 11.

(38) In this embodiment, the contact bridge 26′ is designed as a substantially U-shaped copper part, with the two moving contacts 24a, 24b, each arranged at one free end of a vertical U-shaped member 26′a.

(39) A magnetic element 38′ is respectively arranged in the form of an anchor plate along the vertical U-shaped members 26a′ of the contact bridge 26′. In this embodiment, the drive system 28′ of the contact device 18′ is configured as a hinged armature magnet system, whereby only a more or less U-shaped spring element 46 coupled to the hinged armature is shown. The U-shaped members 26′a and the anchor plates 38′, as well as the U-shaped members 46a are substantially stacked on top of one another.

(40) The vertical U-shaped members 46a of the spring element 46 are substantially arranged flush with the U-shaped members 26a′ of the contact bridge 26′, wherein the horizontal U-shaped members 46b of the spring element 46 are spaced apart from the horizontal U-shaped members 26′b of the contact bridge 26′. In other words, the U-shaped members 46a have a greater length along the longitudinal direction of the member than the U-shaped members 26′a, so that the U-shaped member 46b is arranged above the U-shaped member 26′b along the longitudinal direction of the member.

(41) The spring element 46 is made of a flexible elastic material, e.g. spring steel, so that a swiveling or rotational movement of the drive system 28′ is realized by the substantially free-standing U-shaped member 46b. In particular, the U-shaped members 46a of the spring element 46 are herein held pivotable or rotatable in relation to a swivel or rotation axis S running parallel to the U-shaped member 46b.

(42) In this embodiment, the switching movement is thus carried out, in particular, by swiveling the contact bridge 26′ about the swivel axis S. This swivel movement is indicated in FIG. 7, which shows the contact system 18′ in a closed position, and in FIG. 8, which shows the contact system 18′ in an open position. Comparatively large separation distances between contacts 22a, 22b, 24a, 24b are achieved due to the swivel or rotational movement.

(43) In this embodiment, two stationary magnetic elements 40′ are provided, which are fixed to an insulating, i.e. electrically non-conductive housing 48 of circuit breaker 8. The magnetic elements 40′ are designed in cross-section as horseshoe-shaped or U-shaped magnet yokes, which extend at least in sections along the longitudinal direction of the U-shaped members 26′a, 46′. The magnet yokes 40′ are herein substantially designed as cylindrically-shaped parts with a horseshoe or U-shaped base or cross-sectional area.

(44) The magnetic elements 40′ each have a horizontal U-shaped member 40a′ oriented parallel to the U-shaped members 26′a, 46′ in the closed position. Two vertical U-shaped members 40′b are formed onto the back-like U-shaped member 40a′ of the magnet yoke 40′. In the closed position, the U-shaped members 40′b of the magnet yoke 40′ embrace, at least in sections,—as, for example, shown in FIG. 9—the respective oppositely arranged vertical U-shaped member 26′a of the contact bridge 26′, so that the air gap 42 is formed between the free ends of the U-shaped members 26′a and the respective anchor plate 38′.

(45) As can be seen from the cross-sectional representations in FIG. 10 and FIG. 11, the current I generates a magnetic field B when flowing through the members 26′a, 26′b of the contact bridge 26′, which, independent of the direction of the current, produces the magnetic force Fm, attracting the magnetic elements 38′, 40′ to each other, thus increasing the contact force Fk due to the spring tension of the spring element 46.

(46) The invention is not limited to the embodiments described above. Instead, other variants of the invention can be derived by the person skilled in the art without leaving the scope of the subject matter of the invention. In particular, all individual features described in connection with the examples of implementation can also be combined with one another in other ways without going beyond the scope of the subject matter of the invention.

LIST OF REFERENCE SIGNS

(47) 2 current path 4 direct current power source 4a positive pole 4b negative pole 6 load/consumer 8 circuit breaker 10 power supply connection 12 load connection 14 disconnecting device 15 breaker 16 hybrid switch 18, 18′ contact system 20 semiconductor switching system 22a, 22b fixed contact 23a, 23b connection 24a, 24b moving contact 26 contact bridge 26′ contact bridge 26′a, 26′b U-shaped member 28, 28′ drive system 30 flat surface/lower side 32 flat surface/top side 34 plunger 36 spring element/contact pressure spring 38 magnet element/magnet yoke 38a, 38b U-shaped member 38′ magnet element/anchor plate 40 magnet element/anchor plate 40′ magnet element/magnet yoke 40′a, 40′b U-shaped member 42 air gap 44 recess 46 spring element 46a, 46b U-shaped member 48 housing U operating voltage I current Fk contact force Fm magnetic force Fe constriction force S swivel axis/axis of rotation B magnetic field