EP0006894A1

EP0006894A1 - Protective circuit-breaker operated by leakage current.

Info

Publication number: EP0006894A1
Application number: EP78900088A
Authority: EP
Inventors: Nicolas Gath
Original assignee: Individual
Current assignee: Individual
Priority date: 1977-08-22
Filing date: 1978-08-18
Publication date: 1980-01-23
Also published as: DE2860745D1; WO1979000105A1; IT1098158B; JPS5453275A; LU78012A1; EP0006894B1; IT7826862A0

Abstract

Le conducteur (8) du courant de service est associe a un noyau (3) dont le flux d'induction magnetique provoque, en cas de fuite de courant, la mise en action d'un declencheur. En ce cas, une armature (4) du declencheur tombe en raison de l'interference d'un champ magnetique permanent (11) avec un champ du circuit magnetique du declencheur produit par le courant de fuite. Le noyau (3) est enroule en plusieurs spires autour du conducteur (8) du courant de service; il forme en outre une partie du circuit magnetique (1) du declencheur.The service current conductor (8) is associated with a core (3) whose magnetic induction flow causes, in the event of a current leak, the activation of a trigger. In this case, an armature (4) of the trigger falls due to the interference of a permanent magnetic field (11) with a field of the magnetic circuit of the trigger produced by the leakage current. The core (3) is wound in several turns around the conductor (8) of the operating current; it also forms part of the magnetic circuit (1) of the trigger.

Description

Residual current circuit breaker

The invention relates to a residual current circuit breaker, the operational conductors are chained to a core, the magnetic induction flow in the event of a fault causes the triggering of a trigger by an armature of the trigger drops when a permanent magnetic field is superimposed with a magnetic field caused by the residual current from the magnetic system of the trigger.

In the case of the conventional residual current circuit breakers, the residual current is determined in that the operating current-carrying conductors are wound as coils over the core of a summation current transformer. If a fault current flows, which consists of alternating current, an alternating oil current is generated in a secondary coil, which is conducted through the coil of the magnetic system, with a permanent magnet, of the release. The flow generated thereby reduces the induction flow generated by the permanent magnet and thus the attraction force on the armature of the trigger. The armature is released, it drops, causing the residual current circuit breaker to switch off.

However, if a fault current consisting of direct current flows, it will not be transmitted by the conventional converter and the shutdown will not take place. If the direct current is so strong that the induction of the permanent magnet of the release is in the saturation area, such a residual current circuit breaker no longer reacts as intended even with an additional occurring residual current with AC components.

A residual current circuit breaker, whose magnetic flux in the armature is canceled by superimposing two magnetic fluxes, works on the counter-excitation principle.

According to the blocking magnet principle, the magnetic flux to the armature is prevented. It is known to lead the operating current-carrying conductors directly through pole leg windows of the blocking magnet in a residual current circuit breaker operating according to the blocking magnet principle (DE-OS 19 09 085). With such a residual current circuit breaker, the remanence has a more unfavorable effect than with the current ones

Residual current circuit breakers that work on the counter-excitation principle. This is due to the larger magnetic systems required to hold the armature, since the thick conductors carrying the operating current are placed through a window of the magnetic system, the so-called blocking magnet. The length of the magnetic lines of force is about ten times greater than that of the current residual current circuit breakers that work according to the counter-excitation principle. On the other hand, one does not want to enlarge the dimensions of the armature, since otherwise the energy required to trigger it increases. However, a remanent magnetism existing in the magnetic system has a much stronger effect on a small anchor. The consequences of this remanence can be that the Schialter can no longer remain switched on after a previous shutdown that has left a remanent magnetism.

The object of the invention is to develop a residual current circuit breaker which can respond to direct current components and does without electrical transmission means, such as a secondary coil. The solution to the described problem is that the core itself surrounds the operating current-carrying conductors in several turns and that the core is part of the magnetic system of the release.

In the case of direct current in a certain direction, the residual current circuit breaker can respond, since a direct current fault current can also generate a magnetic flux in the magnetic system of the release because the operating current-carrying conductors are led directly through the core. However, the disadvantages of the known residual current circuit breakers, which operate on the principle of the blocking magnet, are avoided, since the operating current-carrying conductors in the residual current circuit breaker according to the invention cause an increased flow.

A second magnetic system, which responds with direct current of opposite polarity, can therefore be used to build a residual current circuit breaker which responds to direct current fault currents in any direction, as is known per se (DE-OS 21 63 402).

In addition, you can reduce the remanence after further training that the core at least on one Part of its length is divided into two tracks and that on each of these tracks a coil is wound, which is connected to an AC power source, and which together form a magnetic sense of rotation. The core can also be made hollow so that it can receive an electrical conductor which is connected to an AC power source.

A residual current circuit breaker based on the counter-excitation principle can be constructed in such a way that the magnetic system of the trip unit consists of three legs connected to one another at both ends, one leg of which forms the core for the operating current-carrying conductors and in one of which the permanent magnet and the armature of the trip unit are arranged in one of the other legs are. This shortens the path length of the magnetic flux generated by the permanent magnet, which holds the armature, and reduces the leakage flux. You can also build the magnetic system of the trigger from three legs connected to each other at both ends, one of the legs forming the core for the operating current-carrying conductors and the permanent magnet or the armature of the trigger being arranged in the other legs.

A magnetic voltage can be impressed in the magnetic system of the release of the residual current circuit breaker, the induction flux in the magnetic system of the release then becoming independent of the internal resistance of the permanent magnet. This is achieved simply by the permanent magnet resting laterally on one leg of the magnetic system, as is illustrated in FIGS. 4, 5 and 2.

A residual current circuit breaker according to the invention can be used also build up simply by the fact that the magnetic system of the release forms a closed circuit in which at least one permanent magnet lies between the core for the operating current-carrying conductors and the armature of the release and that in the case of two permanent magnets these are arranged in a flow direction.

The invention will be explained in greater detail on the basis of exemplary embodiments shown roughly schematically in the drawing:

1 and 2 illustrate how one can produce a voltage source with an impressed magnetic voltage. 3 shows the basic structure of a residual current circuit breaker.

4 shows a configuration of the residual current circuit breaker. 5 shows a further embodiment of the residual current circuit breaker.

A development of the residual current circuit breaker is shown in FIG. 6.

In Fig. 7, a differently developed residual current circuit breaker is shown.

3 has a magnetic system 1 made of magnetically conductive material. Soft iron or a highly permeable nickel-iron alloy is suitable for this. A core 3, which is wound around the operating current-carrying conductors 8, is part of the magnetic system. The core 3 can consist of soft iron or a highly permeable nickel-iron alloy. This wire is passed, for example, several times through the hole or window of the coils 5, for one conductor 8 carrying operating current. For the sake of simplicity, only one coil 5 for an operating current-carrying conductor 8 is shown in the figures of the drawing. The operating current-carrying conductor 8 could also be implemented simply, ie not in the form of a coil, through the coil-shaped core 3.

Just as with a transformer the electrical voltage of the secondary coil increases the higher the number of turns of the secondary coil, so the magnetic voltage increases with the number of turns of the core. This increases the flooding caused by the conductor carrying the operating current.

3, the magnetic flux for holding an armature 4 is generated by permanent magnets 11a and 11b. The permanent magnets 11a and 11b are arranged in such a way that they generate magnetic induction in one direction of rotation and that as little scatter lines as possible can occur between the armature 4 and the core 3. The armature 4 acts in the usual way on a switching lock 6. 7 shows the direction of rotation of a magnetic induction generated by the permanent magnets 11a and 11b. The core 3 encloses the operating current-carrying conductors 8 in several turns. A minimal distance between the individual turns of the core 3 can be achieved in that a sleeve made of non-magnetic material is drawn around the magnetically conductive material as a spacer.

The arrangement according to FIG. 3 can be connected in series a magnetic voltage source, consisting of the permanent magnets 11a and 11b, with a core 3 and the armature 4. The residual current circuit breaker responds when a residual current in the core 3 generates a magnetic flux against the induction direction 7, so that no or only so little magnetic flux flows through the armature 4 that the armature 4 fall off and the switch 6 can trip. This then causes the supply current-carrying conductors to be interrupted in the usual manner at the provided switching contacts.

To suppress the remanent magnetism, the length of the core according to FIG. 6 can be divided into two tracks. The induction flux conductor of the magnetic system is divided there into tracks 3a and 3b. A coil 61 and 62 is wound on each of these tracks. Coils 61 and 62 are connected at one end at 63 and at their other ends 64 and 65, respectively, to an AC power source 66. The structure otherwise corresponds to that of FIG. 4, the permanent magnet being designated 11. The induction flow generated by the coils 61 and 62 runs in the direction of the circulating sense 7 if the alternating current flows from point 65 to point 64 at the moment of observation.

The induction flow generated by the two coils 61 and 62 runs over the tracks 3a and 3b of the core, but not over the leg of the release magnet with the armature 4. It therefore does not interfere with the magnetic flux that holds the armature 4; however, it reduces the residual magnetic flux. The tracks 3a and 3b of the core advantageously have the same cross section. The remanence can also be reduced by making the core 3 hollow and receiving an electrical conductor 71 which is connected to an alternating current source 66, as illustrated in FIG. 7 with the basic structure according to FIG. 4. Operating current-carrying conductors are drawn in individually, L1, L2, L3, N, and together with 8. 7, the induction flux conductor for the core 3 is, for example, a tube made of soft magnetic material. An electrically insulated copper wire can be passed through this tube. The alternating current flowing through it causes an induction flow which describes a path within the wall of the tube which has the shape of a circle, the center of which lies on the imaginary central axis of the tube.

To shorten the distance that the magnetic flux, which holds the armature of the trigger, has to cover, that is, between a permanent magnet serving as a magnetic voltage source and the armature, the magnetic system 1 of the trigger can be designed according to FIG. 4. This residual current circuit breaker, like the one according to FIG. 3, also works on the principle of counterexcitation. The operating current-carrying conductors 8, only one coil 5 is shown in the exemplary embodiment, are linked to the coil-shaped core 3. The magnetic system 1 of the trigger consists of three legs 41, 42 and 43 which are connected to one another at both ends. The connection points are designated by 44 and 45.

The residual current circuit breaker according to FIG. 4 triggers when the only one coil 5 shown again in the arrangement of the coils 5, of which .s'egen for clarity is flowing current in the core 3 causes a magnetic flux that runs here from left to right. Part of this river flows over the leg 41. Here it overlaps the river holding the anchor - flow direction 7. Since both rivers have opposite directions, the total flow flowing over the anchor decreases and the anchor falls off.

5 can also be constructed from three legs 41, 42, 43 which are connected to one another at both ends, one leg again forming the core 3 for the conductors carrying the operating current and the permanent magnet 11 in the other legs 42, 41 or the anchor 4 are arranged. This fault current circuit breaker also works on the principle of counterexcitation; the anchor 4 thus drops when a flux is induced in the core 3, which - based on the drawing, runs from left to right, that is to say from the connection point 44 via the core 3 to the connection point 45.

If you place a permanent magnet according to FIG. 1 on a flat induction flux conductor, i.e. on a magnetically conductive body, as shown in FIG. 2, the distance between permanent magnet 11 and induction flux conductor 22 being exaggerated, an arrangement is obtained which can be obtained can be referred to as a magnetic voltage divider, that is to say as a voltage divider for magnetic voltage, based on the mode of operation of an electrical voltage divider. The permanent magnet 11 can be regarded as a source of an induction flux, the internal resistance of which is high. 2, most of the induction flow flows from the north pole N via the induction flow conductor 22 underneath to the south pole S. The between the north pole and south pole occurring drop in the magnetic voltage represents part of the original voltage available from the permanent magnet. The arrangement according to FIG. 2 therefore acts externally as a source of magnetic voltage. A tubular permanent magnet, which is magnetized in the longitudinal direction and is pushed over an induction flux conductor according to FIG. 3, also represents such a magnetic voltage source. In both cases, the prerequisite is that the leg portion which is in contact with the permanent magnet or is enclosed by the tubular permanent magnet, is magnetically unsaturated. This means that the flux entering the leg from the permanent magnet is not too strong.

Otherwise, when the magnetic leg is saturated, one has a source of constant magnetic flux, which will be called flow source in the following. A magnetic flux source can also be obtained if an induction flux conductor, for example a leg of the magnetic system, is separated and a permanent magnet is inserted. With such a source, the magnetic flux is constant and quite independent of the magnetic resistance of the connected circuit.

In the three basic versions listed above, for the first two cases, e.g. 3 and 4, the magnetic voltage source is the most suitable, however, for the third embodiment, for. 5, the magnetic flux source is most suitable.

The suppression of the remanent magnetism by an alternating current source 66 in the case of residual current circuit breakers according to FIG. 6 and according to FIG. 7 makes it possible to produce the contact surfaces of the armature 4 precisely ground. One nevertheless avoids the danger that the armature knew stick by remanent magnetism if it should switch off due to a fault current. The construction of a residual current circuit breaker according to the invention can be applied both to circuit breakers that work on the principle of the blocking magnet and to those that work on the principle of counterexcitation. In the illustrated residual current circuit breakers, which work according to the principle of counterexcitation, one can achieve tripping for DC residual currents of any polarity by two systems, one of which responds to one polarity and the other system to the other polarity. Such a circuit breaker can then be equipped with two triggers, the permanent magnets of which are otherwise reversed, otherwise the same design. It is then expedient to connect the two armatures to one another by means of a web and to allow this to act on the switch lock.

7 claims 7 figures

Claims

1. Residual current circuit breaker, whose operating current-carrying conductors are chained to a core, the magnetic induction flow of which triggers a trigger in the event of a fault by an armature of the trigger dropping from the magnetic system of the trigger when a permanent magnetic field is superimposed on a magnetic field caused by the fault current, characterized in that Core (3) in turn surrounds the operating current-carrying conductors (8) in several turns and that the core (3) is part of the magnetic system CD of the release.

2. Residual current circuit breaker according to claim 1, d urcharged that the core is divided at least over part of its length into two tracks (3a, 3b) and that on each of these tracks a coil (61; 62) is wound, which is at an AC power source (66) is connected and which together give a magnetic sense of rotation (7) (Fig. 6).

3. Residual current circuit breaker according to claim 1, that the core (3) is hollow and accommodates an electrical conductor (71) which is connected to an alternating current source (66) (Fig. 7).

4. Residual current circuit breaker according to claim 1 and one of the preceding claims, dadurchgeken nz eichnet that the magnetic system (1) of the trigger consists of three legs (41, 42, 43) connected end-to-end, one leg of which forms the core (3) for the operating current-carrying conductors (8) and in one of the other legs of which the permanent magnet (11) and the armature (4) of the trigger are arranged (FIG. 4).

5. Residual current circuit breaker according to claim 1 and one of claims 2 to 3, dadurchgekennzeic hn et that the magnetic system of the trigger consists of three legs (41, 42, 43) connected end-to-end with one another, one leg (43) of the core (3rd ) for the operating current-carrying conductors (8), the permanent magnet (11) or the armature (4) of the trigger being arranged in the other legs (41, 42) (FIG. 5).

6. Residual current circuit breaker according to claim 4 or 5, that the permanent magnet (11) on the leg (41; 42) bears laterally (Fig. 4, Fig. 5, Fig. 2).

7. Residual current circuit breaker according to claim 1 and one of claims 2 to 3, dadurchgekennzeic hn et that the magnetic system (1) of the trigger forms a closed circuit in which between the core (3) for the operating current-carrying conductor and the armature (4) the trigger has at least one permanent magnet (11a, 11b) and that two permanent magnets are arranged in a direction of flow (7) (FIG. 3).

CHANGED CLAIMS (received at the International Bureau on February 9, 1979 (February 9, 1979))

1. Residual current circuit breaker, the operating current-carrying conductors are chained to a core, the magnetic induction flow in the event of a fault the response of a

The trigger causes an armature of the trigger to drop from the magnetic system of the trigger when a permanent magnetic field is superimposed on a magnetic field caused by the fault current, the core being part of the magnetic system of the trigger, characterized in that the core (3) in turn has the operating current-carrying conductor in several turns Encloses head (8).

INARTICLE 19 DECLARATION

We are asked to replace claim 1 after the annex with the original main claim. This is followed by claims 2 to 7 in the original version.