EP0103167A1 - Circuit breaker with leakage current release - Google Patents

Abstract

1. circuit breaker with fault-current tripping, consisting of adjacently arranged components constructed as switching rows (1, 2) in which the terminal paths for interrupting the phase conductors (L1) and the neutral conductor (N) are accommodated and which contain the latching mechanisms (26), which are coupled to each other, with the thermal (4) and magnetic (3a, 3b) tripping devices, in which arrangement no thermal tripping device (4) is arranged in the switching row (2) of the neutral conductor (N) but only the magnetic tripping device (3b) and components for the latching mechanism which are similar to the corresponding components in the switching rows (1) of the phase conductors (L1), in which arrangement the current path of the neutral conductor (N) is conducted between the connecting terminals (13b, 14b) of the switching row (2) of the neutral conductor (N) via the summation current transformer which also covers the phase conductors (L1), characterized in that a power-system-dependent electronic amplifying device (17) is arranged in the switching row (2) of the neutral conductor (N) and that the tripping coil of the magnetic tripping device (3b), which tripping coil is arranged in the switching row (2) of the neutral conductor (N), is connected to the power system via the amplifying device (17) when a fault current flows in the summation current transformer, as a result of which the magnetic tripping device (3b) is operated by the power system energy, that the neutral conductor (N) is conducted free of interruption through the summation current transformer (16) between the connecting therminals (13b, 14b) and that the amplifying device (17) and the checking device (15) are connected to one of the phase conductors (L1) by means of a connecting line (20a) via an interrupter contact (8a, 9a) the construction of which corresponds to the interrupt contacts (8, 9) of the phase conductors (L1).

Description

The invention relates to a circuit breaker with residual current release, consisting of juxtaposed components (switch alignments), in which the pole paths for the interruption of the phase conductor and the neutral conductor are housed and which contain the interlocked switch locks with the thermal and magnetic triggers, the switching alignment of the Neutral conductor is not a thermal release, but components for the magnetic release and the switching mechanism, which are similar to the corresponding components in the switching alignments of the phase conductors, are arranged, and the current path of the neutral conductor from the connection terminals via the summation current transformer, which also detects the phase conductors, to the interrupter contacts is led.

Residual current is abbreviated below by FI, line protection by LS.

Combined circuit breaker residual current protection switches are known. For example, DE-AS 1 169 015 describes such a switch in which a component which contains the residual current release is attached to a component designed as a circuit breaker transversely to the connecting line of the connection terminals. In this case, a transmission element is provided between the two components for the residual current release to act on the switching mechanism. DE-AS 1 256 775 attempts to solve the problem by arranging the receptacle spaces for the switch contacts in parallel with one another and parallel to the connecting line of the connection terminals in multipole switches and in that the switch space is divided into three parts, in which the switching poles and the arc-quenching device in one room part, short-circuit and overcurrent releases as well as switch mechanics and summation current transformers in a second room part, fault current relays and test equipment are housed in a third room part. In DE-AS 1 280 382 it is again proposed to make the circuit breaker part of each current branch independent of the other circuit breaker pole sections and to check all branches together for fault current. DE-AS 1 563 827 also uses a residual current circuit breaker for a combined residual current circuit breaker, to which independent switches, in particular line circuit breakers, are attached, the switch locks of which are coupled to one another in a suitable manner. In DE-AS 2 754 033, RCD switches and LS switches are connected to one another in such a way that only one common input terminal is present. The connection of two switching mechanisms for the residual current circuit breaker and the circuit breaker is also described in European Patent 0 014 871 and DE-AS 2 654 373. Combined FI-LS switches with line voltage-dependent amplification devices are described in a number of patents described, for example in DE-AS 2 730 874, DE-AS 2 825 881, DE-AS 2 338 785, DE-AS 2 924 122 and UK-PS 1 107 879. However, these solutions only describe the electrical function of the electronic circuits and not the basic structure of the FI-LS switch.

All of the above-mentioned designs are relatively complex and require either an additional switching arrangement or special lock parts and a special magnetic release which is either excited directly by the summation current transformer or responds via an amplifier when the fault current flows with the aid of the mains energy.

In the coming years, the need for miniature circuit breakers with residual current tripping will increase significantly. This is already evident in the development of the installation regulations, whereby the causes lie, on the one hand, in a desire for greater safety in the electrical systems and, on the other hand, in the need for greater reliability of the circuit breakers. In this context, it is known from the literature reference Biegelmeier, Hönniger, The principle of triple security for the protective measures for indirect contact ÖZE 34th vol. (1981), H 6, pp. 185 to 194 (Lit.1) that before For twenty years, an extended scope of protection for protective measures against indirect contact has been proposed as "complete error protection", which, however, was only able to establish itself slowly. The basic idea was to use highly sensitive residual current circuit breakers to protect against direct contact, in addition to the protective measures for indirect contact that were common at the time. With further discoveries and advances in electropathology, these thoughts became important and today, as in the literature reference Biegelmeier, we know about the tripping sensitivity and the tripping times of residual current circuit breakers, E u. M, 98 vol. 1981, H9, pp. 374 to 379 (Lit. 2), presented in detail, very precisely what requirements must be placed on the protective measures for indirect contact with regard to the release times.

However, the principle of triple safety will largely prevail in the coming years (see Ref. 1) and in all electrical systems the socket circuits or rooms with particular risk will be additionally protected by highly sensitive residual current circuit breakers. This development can already be seen in the IEC drafts, in which e.g. this additional protection is required for bathrooms. It is obvious that the required number of circuit breakers with rated fault currents below 30 mA will increase significantly. However, economic issues come to the fore and one will certainly combine overcurrent protection with residual current protection for the protection of these individual circuits, as is already the case with the state of the art. Accordingly, easy mounting and production of the switches is becoming more and more important.

Mounting the switch in the installation has certain difficulties. When connecting the switch, it is necessary to ensure that the mains and consumer side are not mixed up when connecting.

As is well known, every residual current circuit breaker has a test facility, when it is actuated in the switch via an artificial limiting resistor by an artificial fault current flows, which triggers the circuit breaker. This fault current is always higher than the tripping nominal fault current of the circuit breaker. The relevant regulations usually stipulate that when the test device is actuated, the number of excitation winding turns generated by the test current in the current transformer of the circuit breaker must not be higher than 2.5 times the number of ampere turns generated by the nominal value of the tripping fault current . Assuming, for example, a circuit breaker with a nominal tripping fault current of 0.5 A, a maximum of 1.25 A can flow when the test device is actuated. This means that a power of almost 300 W is implemented in the test resistor at a voltage of 220 V. The limiting resistances in the circuit breaker must be kept small for dimensioning reasons. They have nominal powers of a few watts and are therefore heavily overloaded by the test current. If the mains and consumer side are mistakenly swapped when connecting, the circuit breaker trips when the test button is pressed, but the test circuit remains live. If the test button is held in the ON position for a little too long, the test resistor burns out.

The dependence on the connection of the mains and consumer side is even more critical in the case of mains voltage-dependent electronic amplification devices. Devices of this type usually work with transistor amplifiers which, when the fault current flows through the voltage on the secondary winding of the summation current transformer, connect a thyristor whose current actuates the trip coil. However, if the switch is incorrectly connected, the electronic circuit remains energized even after being switched off, and the electronic components are unnecessarily stressed.

For the reasons stated above, the industry has been trying for years to bring residual current circuit breakers onto the market in which the connection of the mains and consumer side can be interchanged as desired.

For example, tries to lead the test circuit over an auxiliary contact, which has its counter contact on the movable switching bridge. If the switch turns off, then this contact is open, so that no current flow through the test circuit is possible even when the test device is operated (DE-PS 877 165). However, this solution has disadvantages. A contact in the vicinity of the main contacts is exposed to the aggressive arcing gases, and in addition, the routing of the test circuit to an auxiliary contact on the movable switching bridge of a main contact is complex in assembly. A similar solution with the same disadvantages is given in DE-PS 1 123 751. It is also expensive to install a thermal switch in the test circuit which is described in DE-PS 1 067 928. Even with a PTC resistor in the test circuit (CH-PS 460 139), the large differences in performance can hardly be mastered.

Several proposals have also been made for mechanical interlocking of the test device actuator. In DE-PS 1 020 404 a test button is used for this purpose, which is coupled to the drive axis of the switch. This solution is also structurally unfavorable because the actuator and test button are spatially dependent on one another and cannot be provided in those places that would be optimal from the point of view of the ease of operation. A mechanical test button lock also describes AT-PS 317 347. All solutions for testing direction, but can not eliminate the difficulties that exist with regard to the adverse influence of the electronic trigger unit if the network and consumer side are connected incorrectly.

The invention now aims to provide a circuit breaker with residual current release which offers significant advantages over the previously known solutions both in terms of economy and in terms of the reliability of the trip. In particular, the line circuit breaker with residual current release should be easy to install, so that when connecting the line and consumer side can be interchanged as desired.

This object is achieved in that a line voltage-dependent electronic amplifying device is arranged in the switching line of the neutral conductor and in that the tripping coil of the magnetic release arranged in the switching line of the neutral conductor is connected to the network via the amplifying device and the summation current transformer, as a result of which the magnetic trip unit flows when a fault current flows is operated.

The magnetic release in the switching alignment of the neutral conductor and the associated switching lock have essentially the same components as the magnetic release and the switching locks in the switching alignment of the phase conductors. The trigger coil of the magnetic release in the neutral circuit with the corresponding number of turns is connected to the mains via the electronic circuit and actuates the magnetic release when a fault current flows. The current path of the neutral conductor is via the summation current transformer from the connection terminals to the breaker contacts. It is achieved by this invention that practically the same components can be used for fault current tripping with the exception of the tripping coil as for overcurrent tripping in the switching lines of the phase conductors. This, however, is extremely economical and, in terms of reliability, the same level is achieved for residual current tripping as was previously the case with overcurrent tripping.

In an advantageous further development, the trigger coil of the magnetic release can be designed in two parts in the switching alignment of the neutral conductor, one coil being connected to the mains via a suitable electronic circuit and actuating the magnetic release when a fault current flows, and the neutral current flowing through the other coil and also actuates the magnetic release when a certain set value of the neutral conductor current is exceeded.

This solution ensures that, in the event of pure short circuits without a fault current to earth, the magnetic release in the switching alignment of the neutral conductor also responds and supports the opening movement of the assigned neutral conductor contact. This reduces the risk of welding the neutral conductor contact.

In order to achieve the required interchangeability of the network and consumer side when connecting, a circuit breaker with residual current release is proposed according to the invention, which carries out one instead of an interrupter contact in the neutral conductor Neutral conductor. The contact that becomes free in the switching alignment of the neutral conductor is used as an auxiliary contact for switching off the mains voltage supply for the test circuit and the electronic amplification device. Figure 7 shows the circuit diagram.

In order that mass production can be carried out as economically as possible, it is proposed according to the invention that the power supply line for the amplifier and test device has an interrupter contact which is similar in structure to the interrupter contacts of the phase conductors.

The current path of the neutral conductor is routed together with the current paths of the phase conductors via the summation current transformer, but is not routed via the break contact, i.e. it connects the two terminals for the mains and consumer-side neutral conductor connection directly. The interrupter contact in the neutral conductor switching alignment is used according to FIG. 7 as an auxiliary contact for switching off the mains voltage supply for the test circuit and the electronic amplification device.

For reasons of mass production alone, the movable contact bridge for the auxiliary contact will be designed in the same way as for a neutral conductor contact, i.e., prematurely closing and delaying opening. Since only small currents flow in the trip circuit, such a contact is extremely oversized and therefore reliable.

However, the invention not only reduces the various components required for such a circuit breaker, but also brings about the same triggering Reliability that was previously common with circuit breakers. The fact that the same switch lock parts are used for the residual current release as for the overcurrent release, results in a robust, reliable and economical switching device, which will be of great importance in the future, particularly for the protection of socket circuits.

In order to increase the ease of installation, it would be conceivable to provide such a device with terminals for the neutral conductor, which are designed in the form of the known neutral conductor disconnect terminals. This would make it easier to locate faults in the insulation of the neutral conductor in the protected system. As is known, in these cases the neutral conductor must be disconnected from the distribution for the insulation resistance measurement.

It is therefore proposed according to the invention to design one or both neutral conductor clamps in such a way that the connection to the neutral conductor can be separated easily and visibly using a tool (screwdriver) without moving it (neutral conductor disconnect terminal). The invention, further advantageous refinements and improvements and further advantages are to be explained and described in more detail with reference to the drawings, in which some exemplary embodiments of the invention are shown.

• Figur 1 eine Aufsicht auf den erfindungsgemäßen Schalter,
• Figur 2 eine Einsicht in den Leitungsschutzschalter,
• Figur 3 eine Einsicht in den Fehlerstrombauteil,
• Figur 4 den magnetischen Auslöser im Leitungsschutzschalter,
• Figur 5 eine weitere Ausgestaltung des Fehlerstrombauteiles und
• Figuren 6 u. 7 zwei Schaltungsanordnungen des Schalters gemäß der Erfindung.

It shows:

• FIG. 1 shows a top view of the switch according to the invention,
• FIG. 2 shows an insight into the circuit breaker,
• FIG. 3 shows an insight into the residual current component,
• FIG. 4 the magnetic release in the circuit breaker,
• Figure 5 shows a further embodiment of the fault current component and
• Figures 6 u. 7 two circuit arrangements of the switch according to the invention.

Figure 1 shows the elevation of a closed circuit breaker, consisting of juxtaposed components (switch alignments) 1 for the phase conductor L1 with the associated terminals 13a and 14a and 2 for the neutral conductor N with the associated terminals 13b and 14b. The actuating member of the circuit breaker consists of switching knobs 12a and 12b coupled together. The coupling of the switch locks inside the circuit breaker is not visible. Furthermore, the circuit breaker, which is designed as a line circuit breaker with residual current release and thus acts, has a test device 15, with which a test circuit is closed when the push button 15a is pressed, in which the test fault current flows. Such a test device as such is known.

FIG. 2 shows the interior of the switching alignment for the phase conductor L1. A connecting conductor 20 runs from the connecting terminal 13a through a first opening 21 in the housing side wall of the circuit breaker, through which it leads to the fault current component (see below). From there it is reinserted into the circuit breaker through a second opening 22 and is connected to one end of a thermal overcurrent release 4. At the other end of the overcurrent release 4 there is a connecting line 23 which leads to the coil of a magnetic release 3a. Its end is electrically conductively connected via a further connecting line 24 to a contact lever 5, the free end of which has a movable contact piece 8 which interacts with a fixed contact piece 9 fastened to an arc guide rail 25 which leads to the terminal 14a. The contact point 8/9 is assigned an arc quenching plate packet 10.

Inside the circuit breaker is a switch lock that consists of a rotatably mounted double arm lever 11 which is articulated to a knee joint lever arrangement 26 at one end; In the area of the knee of the lever arrangement 26, a connecting rod 27 to the switching toggle 12a is provided. The other end of the lever arrangement 26 is attached to the contact lever 5. The double arm lever interacts with a latching lever 28 in such a way that the double arm lever is supported against the arm 28. By means of a transmission lever 29, the movement of the bimetallic strip or the thermal release 4 is transmitted to the latching lever 28, so that under the pressure of a contact opening spring 30 when the lever 28 is pivoted counterclockwise the lock is released, so that the switching mechanism locks the movable contact lever 5 can spend in the off position. The lever 28 is additionally actuated by the magnetic trigger 3a, in such a way that the armature 6 is knocked out to the left of the magnetic trigger 3a when a short-circuit current occurs and thus sets the lever 28 in rotation. At the same time, the armature 6 of the quick release or the magnetic release 3a is additionally connected to the movable contact lever 5 via a mechanical coupling 7, which supports the opening movement of this contact lever. The arc is thereby driven rapidly into the arc-quenching plates 10 by the movable contact lever 5 and the fixed contact piece 9 interacting therewith.

A test line 31 is also connected to the arc guide rail 25 and has a contact point 32 which can be bridged by means of the test device 15. The test line 31 is replaced by a third Opening 33 in the housing leads to the residual current component (see below).

This fault current component is shown in FIG. 3. Corresponding components are used for the component in the arrangement according to FIG. 2, the same reference numbers. Figure 3 shows the interior of the switching alignment for the neutral conductor. The neutral conductor N, which is passed through a summation current transformer 16 and has its other end connected to a contact lever 5, is connected to the connecting terminal 13b. The line 20 is also passed through the summation current transformer, openings 34 and 35 being visible, which correspond to the openings 21 and 22 and through which the line 20 forming the phase conductor is led into and out of the component.

A secondary winding 16a is wound around the summation current transformer 16, which is connected to an amplifier device 17, the output of which is fed to the magnetic release 3b. The amplifier device 17 is supplied with current by means of the supply lines 36.

The test line 31 is introduced into the interior of the fault current component via an opening 37 and is fed to the amplifier 17 via the line section 18. The other connection of the amplifier is connected via a line 38 to the arc guide rail 25, to which the fixed contact piece 9 is attached, which arc guide rail 25 is connected to the terminal 14b.

The amplifier 17 is dependent on the mains voltage and the trigger coil of the quick release 3b is no longer in the main circuit; but becomes an error when flowing current through the amplifier to the mains voltage, whereby the circuit breaker is triggered with the help of the mains energy.

The main current path of the neutral conductor is conducted directly from the connection terminals 13b and 14b via the summation current transformer to the contacts 8/9.

FIG. 4 shows a partial illustration of an electromagnetic quick release with two release coils 3d and 3c. The coil 3d corresponds to the coil of the trigger 3b, lies in the main circuit and flows through the neutral conductor current. In the case of pure short circuits without fault current, it supports the opening movement of the movable contact piece or the contact lever 5 via the mechanical coupling 7. The coil 3c is connected when a fault current flows through the amplifier and thereby triggers the circuit breaker.

FIG. 5 shows the interior of the switching line for neutral conductor N, which is led through the summation current transformer 16, but does not end at the movable contact lever, but is connected to the connection terminal 14b. The neutral conductor N is electrically and galvanically connected via an intermediate line 40 both to a line branch 41 and to a line branch 42, which line branch is introduced into the line circuit breaker component via openings that are not numbered in more detail and contains the test device 15 there. The test device is connected to the fixed contact piece 9 via a conductor 43 and to the amplifier 17 via an intermediate piece 44. Furthermore, the phase conductor 20 is connected to the movable contact lever 5 via a connecting conductor 20a.

The tripping coil of the electromagnetic quick release 3b is no longer in the main circuit, but is connected to the mains voltage when a fault current flows through the amplifier, as a result of which the circuit breaker triggers with the aid of the mains energy. The main current path of the neutral conductor thus connects the terminals directly and leads via the summation current transformer. The power supply line from the test device and amplifier goes from the phase conductor to the break contact, the spring 30 providing the necessary contact pressure.

The mode of operation of the arrangement according to FIGS. 3 and 5 is illustrated in more detail with reference to FIGS. 6 and 7.

FIG. 6 shows the circuit arrangement of the component according to FIG. 3 including test device 15. The terminals of the phase conductor are 14a and 13a and those of the neutral conductor 14b and 13b. The terminals 14a and 14b are connected to the network and the terminals 13a and 13b are connected to the consumer. The test device is arranged at one end behind the contact point 8/9 in the phase conductor L1, so that when the contact point 8/9 has opened, no more current can flow to the amplifier via a series resistor 50 when the test device 15 is closed. However, if the network is connected to terminals 13a and 13b and the consumer side to terminals 14a and 14b, then there is the problem that when the test device 15 is closed, the full current on the network side can be applied to the test device 17. It can be seen that the configuration according to FIGS. 3 and 6 is dependent on the position in any case; the two pairs of terminals must not be confused with each other will.

This is not the case with the embodiment according to FIG. 7. It can be seen that the supply line leads from the phase conductor L1 to the test device via the contact point 8a / 9a, which opens when triggered together with the main contact point 8/9. This makes it irrelevant whether mains voltage is present at the terminal pairs 14a / 14b or at the terminal pairs 13a / 13b. In any case, the line to the test device 15 is opened by the two contacts 8a / 9a.

Claims (4)

1. Miniature circuit breaker with residual current release, consisting of components (1, 2) (switch alignments) arranged side by side, in which the pole sections for the interruption of the phase conductor (L1 70) and the neutral conductor (N) are housed and which interconnect the switch locks (5, 11,26) with the thermal (4) and magnetic (3) triggers, whereby in the switching alignment (2) of the neutral conductor a thermal release is not, but components for the magnetic release and the key switch, which correspond to the corresponding components in the switching alignment of the Phase conductors are the same, are arranged, and the current path of the neutral conductor (N) is led from the connection terminals (13b, 14b) via the summation current transformer, which also detects the phase conductors, to the interrupter contacts (8, 8a; 9, 9a) that in the switching alignment (2) of the neutral conductor (N) a mains voltage-dependent electronic amplification device (17) is arranged and that in de r Switching alignment (2) of the neutral conductor (N) arranged release coil of the magnetic release (3b) is connected to the network via the amplifying device and the summation current transformer (16), whereby the magnetic release (3b) is actuated when a fault current flows. , 2. Leitunhgsschutzschalter with residual current release according to claim 1, characterized in that the trigger coil of the magnetic release, which is housed in the component of the neutral conductor, is designed in two parts, with a coil (3b) on the mains voltage-dependent electronic amplification device (17) is connected to the mains and actuates the magnetic release when a fault current flows and the neutral current flows through the other coil (3c) and also actuates the magnetic release when a set value of the neutral current is exceeded. 3. Miniature circuit breaker with residual current release according to claim 1, characterized in that the mains lead (20) for amplifier and test device leads via an interrupter contact (5, 8, 9) which is similar in structure to the interrupter contacts of the phase conductors. 4. Miniature circuit breaker with residual current release according to claim 1 and / or 2, characterized in that the connecting terminals for the neutral conductor (13b and / or 14b) are designed such that the connection to the neutral conductor by means of a tool (screwdriver) without moving it, can be separated easily and visibly (neutral conductor disconnect terminal).

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