DE19734676A1 - Line protection switch with two series-connected switch points - Google Patents

Abstract

Each extinguishing chamber has two fixed switch contacts, each with a fixed contact, a movable, fork-shaped bridge member (23) with two counter contacts (24, 24'). Each of the latter coacts with one fixed contact, while free ends of the contacts form light arc conductors (26, 26'). Each of the latter has a first section (261, 261'), applicable to each fixed contact and counter contact and moving obliquely to the partition. The first sections of the fixed contacts and the bridge member lie at the shanks of a V-opening towards the extinguishing baffles.

Description

TECHNICAL AREA

The invention is based on a switching device according to the preamble of claim 1. Such switching devices are preferably as line protection trained switch and then serve to protect lines in one Low-voltage network against impermissible, short-circuit or overload caused warming. The effect of a large short circuit current is it is desirable that this device switches off quickly, so that the disconnected line and the associated consumer from excessive To protect warming.

STATE OF THE ART

The invention relates to a prior art as described in CH 543 174 is specified. A line protection described in this prior art switch contains two switching points connected in series. These switching points is each one of two each containing fire-fighting sheets and by a partition arcing chambers spaced apart from one another. The quenching chambers are each surrounded by a U-shaped iron jacket. The switch points also two fixed contact pieces, each with a fixed contact and one Movable, fork-shaped bridge contact piece with two each one of the two fixed contacts cooperating counter contacts and Arc guiding elements, which form the free ends of the contact pieces. At the Two of the current to be switched off are switched off between the contacts flowing arcs. These arcs are created by yourself generated, in the iron jacket reinforced magnetic fields along the arc guide elements pushed into the quenching chambers, cooled on the quenching plates and deleted.  

An electrical contact arrangement for a switching device with two in series Switching points is published in EP 0 736 887 A2. Bridged on this switching device in the closed position one movable bridge contact two fixed arranged and each connected to a power connector. At the Two contacts switch off in opposite directions from Arcs through which the current flows are formed, which are caused by the force their own magnetic fields directed away from each other on deflectors and then be deleted.

SUMMARY OF THE INVENTION

The invention, as specified in claim 1, is the object based on specifying a circuit breaker of the type mentioned, the despite the narrow width across the partition, it can be switched off particularly quickly enables.

In the switching device according to the invention, the arc guiding elements of the two fixed contact pieces and / or the bridge contact piece each one each of the two fixed contacts and / or on each of the two counter contacts starting section, which runs obliquely to the partition. On the two fixed contact pieces and / or sections located on the bridge contact piece each lie on the legs of one facing the quenching chamber or Extinguishing sheets opening V. Arcs formed when switching off bump because of their own magnetic fields and become oblique to the partition extending sections of the arc guide elements away from each other outwards and at the same time also led into the arcing chambers. Depending on the size of the angle between the partition and the arc guide elements act accordingly dimensioned force components on the arcs, which the arcs with drive correspondingly high speeds into the quenching chambers. the period the arc from the contacts into the quenching chambers is considerably shortened and thus a particularly quick extinguishing of the arcs or a quick one Interruption of the current to be switched off reached. Particularly effective Force components in the direction of the arcing chambers are reached when the  Opening angle of the V is between approx. 30 ° and 120 °. If the angle is less than 30 °, so only relatively small force components act on the arcs. Is the angle greater than 120 °, large force components act on the arcs, however the arcs are then pushed far away from the partition. The switching device must then be undesirably wide. With regard to the Switch-off speed and the dimensions of the switching device as special An opening angle between 50 ° and 100 ° has been found to be advantageous.

Preferred embodiments of the invention and the others achievable therewith Advantages are explained below with reference to drawings.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 is a side view of the contact arrangement and arc chutes of a circuit breaker designed as a first embodiment of the switching device according to the invention in the off state upon opening of its housing,

Fig. 2 is a plan view to the left on a longitudinal section through II-III guided the switching device according to Fig. 1,

3 is a plan III-II on the longitudinally guided to the right section.,

Fig. 4 is a perspective view of the contact arrangement and the extinguishing chambers of the switching device of FIG. 1 from the left;

Fig. 5 is a perspective view of the contact arrangement and the extinguishing chambers of the switching device of FIG. 1 from the right,

Fig. 6 is a side view of the contact arrangement and arc chutes of a circuit breaker designed as a second embodiment of the switching device according to the invention in the off state upon opening of its housing,

Fig. 7 is a plan view to the left of a section taken along VII-VIII through the switching device according to Fig. 6, and

Fig. 8 is a right view of the section taken along VII-VIII.

WAYS OF CARRYING OUT THE INVENTION

The switching device shown in FIGS . 1 to 5 has an insulating material housing 10 , in which a contact arrangement 20 and two quenching chambers 30 , 30 'with quenching plates 31 , 31 ' spaced apart by a partition 11 made of insulating material are accommodated. The contact arrangement comprises two fixed, essentially mirror-symmetrical switching pieces 21 , 21 ', each with a fixed contact 22 , 22 ', and a fork-shaped bridge switching piece 23, which is movable by a drive (not shown) and has two mating contacts, each of which cooperates with one of the two fixed contacts 22 , 22 ' 24 , 24 '.

The fixed switching pieces 21 and 21 'are in electrically conductive connection with one of two power connections, not shown, of the switching device. The free end of the fixed switching element 21 or 21 'which faces away from the power connection (not shown) is in each case curved downward in the direction of the assigned arcing chamber 30 or 30 ' and serves as an arc guiding element 25 or 25 '. It is guided downwards past the upper part of the assigned arcing chamber 30 or 30 '.

The two fork ends of the bridge contact piece 23 are also each formed downward in the direction of the respectively assigned quenching chambers 30 and 30 'and serve as arc guiding elements 26 and 26 '. In contrast to the fixed contact pieces 21 and 21 ', the arc guiding elements 26 and 26 ' are only guided up to the upper edge of the associated quenching chamber 30 and 30 '. In the switched-off position of the switching device, the arc guiding elements 26 and 26 'interact with fixed arc guiding rails 27 and 27 ', which, in accordance with the arc guiding elements 25 and 25 ', lead past the upper edge of the quenching chambers downwards.

The arc guiding elements 25 , 25 ', 26 and 26 ' each have a section 251 , 251 ', 261 and 261 ' which is attached to the associated contact 22 , 22 ', 24 and 24 ' and is guided at an angle to the partition 11 . These sections are located on the legs of a to the quenching plates 31 or 31 'opening towards V. The portion 251, 251', 261 or 261 'is followed by a guided parallel to the partition wall 11 portion 252, 252', 262 and 262 ', which extends past the upper edge of the assigned arcing chamber 30 or 30 ' downwards.

The arc guide rails 27 and 27 'are interconnected. As with the bridge contact piece 23, this connection can be arranged at the top in the region of the sections 262 and 262 'of the bridge contact piece or at the bottom at the bottom of the arcing chambers 30 and 30 '.

The operation of this switching device is as follows: In the switched-on state, the bridge contact piece 23 rests on the two fixed contact pieces 21 and 21 '. Current is now conducted from the fixed contact 21 via its fixed contact 22 , the mating contact 24 of the bridge contact 23 , an unspecified contact carrier, the mating contact 24 'and the fixed contact 22 ' to the fixed contact 21 '. When switching off, the bridge contact piece 23 is removed from the fixed contact pieces 21 , 21 'by the drive (not shown) and brought into the position shown in the figures. In this case, two switching points lying in series with one another and through which the current to be switched off flow are opened and two switching arcs are formed. The force of the magnetic fields of these two arches causes them to repel each other and quickly separate them. The base points of the arcs on the sections 251 , 251 ', 261 and 261 ' running obliquely to the partition 11 are quickly removed from the contacts 22 , 22 ', 24 and 24 ' used for continuous current transmission and first outwards and downwards and then after impact led to the sections 252 , 252 ', 262 , 262 ' exclusively down to the arcing chambers 30 and 30 '. The running time of the arcs from the contacts into the quenching chambers is thus considerably shortened, thereby achieving a particularly rapid quenching of the arcs or a quick interruption of the current to be switched off.

In the second embodiment of the switching device according to the invention shown in FIGS. 6-8, the angle between the partition 11 and the section 251 , 251 ', 262 and 262 ' is smaller than in the previously described embodiment. The effective component of the force generated by the magnetic fields is then less. The switching arcs are then not removed from contacts as quickly as in the previously described embodiment, but the force then acts over a longer distance and, with the same width of the switching device, the switching arcs can then be inserted into the quenching plates 31 , 31 'of the quenching chambers in a particularly secure manner 30 , 30 'are pushed.

It is not necessary for the arc-guiding elements of all switching elements to have sloping sections 251 , 251 ', 261 , 261 '. For an application which is improved compared to the prior art, it is sufficient if these sections are provided either only on the two fixed contact pieces 21 , 21 'or only on the bridge contact piece 23 .

Reference list

10th

Insulating housing

11

partition wall

20th

Contact arrangement

21

,

21

'' fixed contact pieces

22

,

22

'Fixed contacts

23

Bridge contact

24th

,

24th

'Counter contacts

25th

,

25th

,

26

,

26

'' Arc guide elements

27

,

27

'' Arc guide rails

251

,

251

',

261

,

261

'first sections

252

,

252

',

262

,

262

'second sections

30th

,

30th

'' Fire chambers

31

,

31

'' Extinguishing sheets

Claims (4)

1. Switching device, in particular a circuit breaker, with two switching points connected in series, to which one of two quenching chambers ( 30 , 30 '), each containing two quenching plates ( 31 , 31 ') and spaced apart by a partition ( 11 ), is assigned, with two fixed ones Switching pieces ( 21 , 21 '), each with a fixed contact ( 22 , 22 '), a movable, fork-shaped bridge switching piece ( 23 ) with two counter-contacts ( 24 , 24 ') each interacting with one of the two fixed contacts ( 22 , 22 ') and with arc guiding elements ( 25 , 25 ', 26 , 26 ') forming the free ends of the switching elements ( 21 , 21 ', 23 ), characterized in that the arc guiding elements of the two fixed switching elements ( 21 , 21 ') and / or the bridge switching element ( 23 ) one at each of the two fixed contacts ( 22 , 22 ') and / or at each of the two counter contacts ( 24 , 24 '), which is guided at an angle to the partition ( 11 ) has section ( 251 , 251 ', 261 , 261 '), and that the first sections located on the two fixed contact pieces and / or on the bridge contact piece are each on the legs of a V opening towards the extinguishing plates ( 31 , 31 ') . 2. Switching device according to claim 1, characterized in that the Opening angle of the V between 30 ° and 120 °, preferably between 50 ° and 100 °. 3. Switching device according to one of claims 1 or 2, characterized in that on the first section ( 251 , 251 ', 261 , 261 ') a second section ( 252 , 252 ', 262 , 262 ) guided parallel to the partition ( 11 ) ') connects. 4. Switching device according to one of claims 1 to 3, characterized in that two with the two arc guide elements ( 26 , 26 ') of the bridge contact ( 23 ) cooperating, fixed and electrically conductively connected arc guide rails ( 27 , 27 ') are provided with accordingly the free ends of the arc guiding elements ( 26 , 26 ') are formed and interact with them when the rail ends are switched off.