EP0813218B1 - Trip device for overload circuit breaker - Google Patents

Description

The invention relates to a tripping device for an overcurrent breaking device, such as e.g. Circuit breaker comprising a switch-actuated tripping armature, which can be actuated by a coil through which a current to be monitored flows, wherein the trigger armature indirectly by means of at least one elastic Coupling link and optionally one or more auxiliary anchors with the trip anchor connected, can be actuated by the coil directly movable magnetic armature. On overcurrent shutdown devices are essentially on the one hand fuses-they are only usable for a single shutdown and on the other re-activatable, therefore repeatedly usable circuit breaker in use.

In an electrical system is usually in the supply line overload protection of cited construction methods provided before this supply line in a variety of parallel divides circuits connected to each other. In each of these circuits are own Protective devices -in the rule consisting of personal protection (FI-circuit breaker od. Like.) and system protection (circuit breaker, fuses od. Like.) - Provided. If necessary, these circuits can turn into further, as well by Safeguards split further sub-circuits.

In such a circuit structure, there is a series connection of Protection of supply line, circuit and sub-circuit.

If an inadmissibly high current occurs in a subcircuit, it is desirable to if only the circuit breaker associated with this subcircuit triggers and thus disconnects its sub-circuit from the mains, however, all upstream circuit breakers switched on and thus all trouble-free circuits and sub-circuits with the network stay connected. Only when the occurring overcurrent is so great that it is no longer from the Circuit breaker of the sub-circuit can be turned off, the parent Address switch. Such a time-delayed switching of the upstream switch is referred to as "selectivity".

For fuses, this selectivity is due to the melting of the Melting wire required heating power, which is proportional to the square of the amperage and the duration of action of the overcurrent is determined.

In the field of circuit breakers are usually two tripping devices intended. A first device is for switching off only slightly above that Plant rated current lying over longer periods acting overcurrents provided. The second, so-called short-circuit current tripping is usually by a from to monitoring current flowing through coil with moving, causing the shutdown Anchor realized. To that explained in connection with the fuses To simulate the heating power and hence the current-dependent and time-dependent delay, are used by the current to be monitored through the flow of thermo-bimetallic strip, which bimetallic strip is analogous to the enamel wires proportional to the square of Current and time deform and delayed by this deformation the Enable switching operation of the short-circuit current tripping.

These bimetallic strips represent components that are mechanically precisely adjusted on the one hand and on the other hand require additional electrical connections. In summary So they bring a significant complication of the circuit breaker construction and thus a Deterioration of functional reliability and a more complicated production with it.

DE-C-438 518 shows a trigger of an overcurrent relay comprising a coil and an armature movable therefrom. Furthermore, a displaceable rod is provided, which is coupled to the armature via a helical compression spring. On the rod acts a timer, which allows a slow movement of the rod.

GB-PS-522 303 corresponds in function and structure substantially to DE-C-438 518 :

Again, there is a cylindrical coil within which a tubular magnet armature is arranged. Inside this magnet armature is a helical compression spring, which is supported at one end on the armature and the other end of the collar-shaped extension of a rod. This rod is formed by the armature piercing and communicates with a timer. If the solenoid is traversed by an overcurrent, the armature is pulled up while compressing the compression spring, because the rod is temporarily held by the timer. As a result, the compression spring expands, moving the rod upwards, this movement being inhibited by the timer as in DE-C-438 518 and thus slowed down.

The object of the invention is a triggering device of the type mentioned which has a selective triggering behavior, but only a few few, insensitive and easy to install to the conventional trip coil Has to be added components.

Other objects of the invention are located therein, the simplest possible ways of generating said holding power, options for adjusting the selectivity and in practice implementable, functionally reliable design examples of the invention Indicate triggering device. This is achieved by the recited in the subclaims Measures achieved.

In a tripping device for an overcurrent shutdown device, such. Circuit breaker comprising a switch-actuated tripping armature, which can be actuated by a coil through which a current to be monitored flows, the object is achieved in that the release anchor only in his Rest position is held with a predetermined holding force, and after exceeding this holding force starts moving suddenly.

It is thus a time delay of the switching action by electro-mechanical measures or arrangements possible, which compared to electrothermal-mechanical solutions is much more functionally reliable.

According to a first variant of the invention can be provided that the holding force on force generated by mechanical means, resulting in a robust and compact design of the triggering device according to the invention leads.

In this context, it may be provided that the holding force is a static friction force which is producible by components in contact with the triggering armature.

By changing the contact pressure exerted by the components on the release armature the holding force can be adjusted very easily.

According to another embodiment of the invention can be provided that the Holding force by acting on the trigger armature resilient components, such. a Snap spring is generated.

This can easily relatively large holding forces and thus strong Time delays are realized.

According to a preferred embodiment of the invention can be provided that the Holding force a magnetic, by at least one acting on the trigger anchor Permanent or electromagnet generated force.

Such systems show relatively accurately predictable and environmental influences constant magnetic properties, so that provided with triggering devices about the lifetime have almost constant time delays.

It may be advantageous that the holding force acting on the release armature changeable is because so the time delay of the triggering process changeable and with a switching device according to the invention provided switching device on him downstream protective devices is adjustable.

In this context, it may be particularly advantageous if it is provided that the Holding force is variable depending on the strength of the monitored current. For an adaptive behavior of the triggering device can be realized; depending on the size of the Short-circuit current increases the relative switch-off delay automatically.

In a further development of the invention can be provided that the holding force of a Electromagnet, which is directly proportional to the current to be monitored Electricity is flowing, can be generated.

This allows a particularly simple and functionally reliable implementation of the above described current-dependent holding force change.

Another feature of the invention may be that the at least one elastic Coupling member is formed by a coil spring, because such components have little space but at the same time have good and constant elasticity.

According to a particularly preferred embodiment of the invention can be provided that the magnetic armature is at least partially disposed in the interior of the coil. Thus, the magnetic anchor is exactly predictable by the magnetic forces of the current to be monitored.

In development of the above preferred embodiment can be provided that the Trigger armature is located inside the coil, the release armature is not off magnetizable material is formed.

This results in a relatively compact size of the triggering device.

Furthermore, it can be provided that the magnet armature as unilaterally closed pipe section is formed and that the triggering armature and the at least one coupling member at least are partially disposed within the cavity formed by the magnet armature. This allows a further geometric reduction of the tripping device according to the invention, it is essentially only dependent on the size of the coil, outside There are no moving parts anymore.

In a further embodiment of the invention can be provided that the release anchor a passing through the magnet armature, preferably parallel to the longitudinal axis of the Coil extending approach has on which approach the holding force acts.

Thus, the holding force introducing components can be arranged outside of the coil be so that they are arranged in the interior of the coil components in their Do not obstruct freedom of movement in any way.

Fig. 1 eine schematische Schnitt-Darstellung einer erfindungsgemäßen Auslöse-Einrichtung im Aufriß;

Fig.2 die Auslöse-Einrichtung nach Fig.1 mit einem zusätzlichen Hilfsanker;

Fig.3a,b die Auslöse-Einrichtung nach Fig.1 mit Bauteilen zur mechanischen Aufbringung der Haltekraft;

Fig.4 eine mögliche konkrete Ausführung der Erfindung im Aufriß im Schnitt;

Fig.5 eine andere mögliche Ausführung der erfindungsgemäßen Auslöse-Einrichtung im Aufriß im Schnitt und

Fig.6 die Ausführung nach Fig.5 ergänzt um zwei mögliche Varianten der elektrischen Beschaltung der Auslöse-Einrichtung.

The invention will be explained in more detail below with reference to the accompanying drawings. Showing:

Figure 1 is a schematic sectional view of a tripping device according to the invention in elevation.

2 shows the triggering device of Figure 1 with an additional auxiliary anchor.

3a, b, the triggering device of Figure 1 with components for the mechanical application of the holding force.

4 shows a possible concrete embodiment of the invention in elevation in section;

5 shows another possible embodiment of the tripping device according to the invention in elevation in section and

Fig.6 the embodiment of Figure 5 supplemented by two possible variants of the electrical wiring of the tripping device.

The tripping device for an overcurrent disconnecting device shown in Fig. 1, e.g. Circuit breaker, has a magnetic armature 5 consisting of a magnetizable Material such as iron, which magnetic armature 5 of a coil. 3 is directly movable. The current flowing through the coil 3 is the to be monitored and optionally off current itself. Furthermore, a trip anchor 1 provided, which can operate a switching mechanism 20, which 20 switching mechanism to from monitoring current flowing through contacts 21 opens. This operation can be as in the drawing shown on an integrally formed on the trigger anchor 1 trigger pin. 2 take place, alternatively, however, also carried out directly from the release anchor 1 itself become.

Mechanically, release armature 1 and magnetic armature 5 are connected to each other by an elastic coupling member 4, which is formed in the simplest case by a coil spring. The release armature 1 is not freely movable, but held with a predetermined holding force F _H in its rest position. In order to bring the release anchor 1 after tripping back into its rest position, a return spring 6 is provided, which is supported on the one hand on the release armature 1 and the other on a-only symbolically represented-housing part 7.

By this arrangement, the occurrence of an inadmissibly high and therefore to be switched off overcurrent reaches a time-delayed tripping.

Said triggering can be divided into two trigger phases, which are described below. In a first, the occurrence of the overcurrent immediately following the tripping phase, the overcurrent generated via the coil 3 a magnetic field proportional to its strength, which moves the magnetic armature 5 in the direction of the tripping armature 1. This movement is transmitted via the elastic coupling member 4 on the release armature 1, which, however, provisionally still-due to the holding force F _H acting on it remains - in its rest position. With further progressive deflection of the magnetic armature 5, the coupling member 4 is biased more and more, whereby the force acting on the trigger armature 1 increases. In this tripping phase magnetic armature 5 and coupling member 4 represent a vibration system which is energized by the magnetic force generated by the overcurrent. The time required by the magnetic armature 5 to bias the coupling member until the holding force F _{H is} exceeded and the trigger armature 1 is deflected from its rest position results in the time delay, the selectivity of the tripping device according to the invention.

If the force generated by the overcurrent exceeds the holding force F _H , the second tripping phase occurs. The release armature 1 comes suddenly in motion, whereby the switching mechanism 20 is actuated and subsequently the contacts 21 of the overcurrent protection device are opened. In this tripping phase, the now coupled masses of magnet 5 and tripping armature 1, in cooperation with the return spring 6, constitute the oscillation system. This functions like a conventional magnetic triggler, formed only from coil and armature, the excitation force resulting from the result of the force system Current force holding force F _H results.

The triggering is summarized so not by a direct through the overcurrent actuated armature initiated, but takes place indirectly by the movement of the means of elastic coupling member 4 connected to the trigger armature 1, from the coil. 3 directly movable magnetic armature 5.

The time delay of the triggering is essentially in the first triggering phase created. It is characterized by the mechanical properties of the vibration system -Magnet anchor mass, Spring rate of the coupling member 4 and Magnet Ankerhub- and through the Current determined. The current force is known to be proportional to the square of the current, Consequently, the movement of the magnetic armature 5. Thus, the delay to Current square proportional, just as in the aforementioned known, electrothermal functioning delay devices.

Although this would complicate the structure of the tripping device according to the invention, it is also quite conceivable, as shown in Figure 2, a - possibly even more auxiliary armature 11 to be arranged between the magnet 5 and the tripping armature 1. One behind the other, these auxiliary anchors 11 are mechanically connected via further elastic coupling members 40 and are acted upon analogously to the release anchor 1 in their rest positions with holding forces F _H. Such a mechanical series connection of several anchors leads to an addition of their holding forces F _H as well as to an enlargement of the deflection path to be traveled by the magnet armature 5 and thus to an extension of the delay time.

Described holding forces F _H can be generated in principle in any way. FIGS. 3a and 3b show examples of the holding force generation by mechanical means. According to Figure 3a, the holding force F _{H is} a static friction force, which is produced by standing in contact with the trigger armature 1 components 8, which pinch the trigger armature 1 between them.

The alternative according to FIG. 3 b provides for the holding force F _{H to be} generated by resilient components 9, such as a snap spring, acting on the release armature 1. This snap spring 9 is designed as a clamped on both sides and biased against the direction of movement of the trigger armature 1 leaf spring. If the force acting on it is large enough, it bends against its biasing direction, allowing movement of the trigger armature 1.

A contrary to these mechanical solutions type of holding force training is located in that the holding force F _{H is} a magnetic force generated by at least one acting on the tripping armature 1 permanent or electromagnet force. Examples of these are shown in FIGS. 4, 5 and 6. These drawings illustrate practical embodiments of the invention.

Here, the coil 3 is arranged on a non-magnetic winding body 10, wherein the Magnetic armature 5 is arranged in sections inside the coil 3. Furthermore, there is a yoke 23 provided of magnetizable material, the majority outside the coil. 3 runs and has a projection 24, which is closer to the switching mechanism 20 located at the end of Spool 3 protrudes into this. The magnetic field generated by a coil current closes via the yoke 23, the magnet armature 5, the working air gap a and the yoke 24.

This structure corresponds to the conventional, conventional design of a Magnetic release. Also, the trigger armature 1 is disposed inside the coil 3, must however, of non-magnetizable material, e.g. Aluminum or plastic be formed so that it is not moved by the magnetic forces generated by the coil 3 becomes.

The magnet armature 5 is formed as a closed side pipe section, wherein the Tripping armature 1 and the coupling member 4 within the magnetic anchor 5 formed Cavity are arranged.

The release armature 1 has a release pin 2 extending out of the coil 3 and is analogous to the illustration of Figure 1 by a return spring 6 in its rest position brought.

To allow the holding force to act on the release anchor 1, this one has passing through the magnet armature 5, preferably parallel to the longitudinal axis of the Coil 3 extending approach 12. This has freely accessible and therefore with forces loadable sections.

The approach 12 is not mandatory to provide, within the meaning of the invention, it is equally possible to let the holding forces F _{H act} directly on the trip anchor 1. For this purpose, however, the components required for this would have to be arranged in the interior of the coil 3, if appropriate recesses for them in the magnetic armature 5 are provided, so that it is not hindered in its freedom of movement.

As already indicated, the holding force F _H in this embodiment is generated by magnetic means, specifically by means of a permanent magnet 13. For this purpose, an anchor 26 is set at the upper end of the neck 12. Together with the yoke 25, which simultaneously serves as a mechanical support for the permanent magnet 13 according to Figure 4, and the permanent magnet 13, the armature 26 forms a magnetic circuit for the magnetic field generated by the permanent magnet 13. By resulting in this arrangement holding forces between the armature 26 and the yoke 25 of the release armature 1 is held in the illustrated rest position.

In said magnetic circuit formed by armature 26, yoke 25 and permanent magnet 13, there are air gaps 27 between armature 26 and yoke 25 and an air gap 28 between permanent magnet 13 and armature 26. The resulting holding forces F _H can be achieved by changing the size of these air gaps 27, 28 to be changed. Said air gap change can be achieved, for example, by selecting the height of the permanent magnet 13, by differently thick, arranged between the yoke 25 and armature 27 deposits of non-magnetizable material, by changing the length of the yoke legs or similar measures.

Upon the occurrence of a short-circuit current increases the strength of the prevailing in the working air gap a between the magnet armature 5 and the yoke 24 magnetic field and thereby acting between magnetic armature 5 and approach 24 attracting forces, causing the magnetic armature 5 moves toward approach 24. After the tripping armature 1 still stands still, the distance d between the magnet 5 and the tripping armature 1 decreases, the spring 4 being compressed. As soon as the forces transmitted via the spring 4 to the tripping armature 1 exceed the holding force F _{H of} the permanent magnet 13, the tripping armature 1 is also set in motion and as a result the tripping is triggered via the switching mechanism 20.

If the entire distance d from the magnet armature 5 are run through without this Movement of the tripping armature 1 has been reached, the magnetic anchor 5 strikes the Release anchor 1 and takes this in its further downward movement. In this Aufeinanderschlagen it comes to a shock process in which the magnetic armature. 5 Movement energy is withdrawn, which in turn delays the switching action and thus contributes to the selective shutdown of the device.

Important for the proper functioning of the described arrangement is the Dimensioning of the distances a, b, c, d. In particular, the distance d between magnet 5 and release armature 1 may be smaller than the distance a between magnet armature 5 and Jochansatz 24, so that is ensured that at the end of the possible path of movement of Magnetic anchor 5 -er then meets the yoke approach 24 on the release anchor 1, the switch lock 20 has pressed. In this connection, it is necessary that the movement path of the Tripping armature b is sufficiently long to operate the switching mechanism 20. It must continue be excluded that the armature 26 during the movement of the trigger armature 1 on Winding body 10 impinges and thus holds the trigger anchor 1. This will be done achieved that the distance c is greater than distance b.

In summary, for the ratios of the distances a, b, c, d the following relationships are given: a> b and a> d, and c> b.

The particularly preferred embodiment of Figure 5 is consistent with that of Figure 4 largely the same, but here is the permanent magnet 13 by an electromagnet - formed from winding 15 and yoke 25- replaced. As above is one with the approach 12th connected armature 26 is provided which forms a magnetic circuit with the yoke 25. For the mechanical support of the electromagnet, a separate component 14 is provided. For the Dimensioning of the distances is what is said in the description of Fig.4.

The change in the holding force F _H can also be done here again on the adjustment of the lengths of the air gaps 27,28. It is particularly advantageous not to provide the air gaps 27, so the armature 26 to rest on the yoke 25 and to make the inside of the winding 15 extending portion 25 'of the yoke 25 in the longitudinal direction of the winding 15 slidably. Thus, the holding force F _H can be adjusted by mechanical means.

In addition to this mechanical variability, the holding force F _{H can} also be changed by changing the current flowing through the winding 15. However, the variability of the holding force F _H is by no means limited to magnetic force generation. Also indicated in Figure 3a components 8 may be slidably disposed whereby the contact pressure on the release armature 1 and thus the holding force F _H can be changed.

It is particularly favorable if the holding force F _H is variable as a function of the strength of the current to be monitored. In the design variant according to FIG. 5, this can be realized in a particularly simple manner by virtue of the fact that the current flowing through the winding 15 is directly proportional to the current to be monitored.

In order to have the lowest possible circuit complexity, the mentioned proportionality is most easily achieved in that the overcurrent itself flows through the winding 15 of the electromagnet. For this purpose, as shown in FIG. 6 with continuous connecting lines 16, 17, the coil 3 and the winding 15 are connected in series with one another. For the same purpose coil 3 and winding 15 could, however, also be connected in parallel -Vgl. dashed connecting lines 18, 19; In this case, 15 series impedances can be switched in branch of the winding to adjust the current flowing through the winding 15 and thus the generated holding force F _H.

Although this would entail a relatively high overhead, it is in the sense of Invention equally possible, the winding 15 with a galvanic to be monitored from Electricity to apply separate power and this possibly also via appropriate Control circuits proportional to the overcurrent change.

A preferred field of application of the described triggering device according to the invention is in use in circuit breakers, but this is the application in other, over-current disconnecting devices should not exclude.

Claims (14)

1. A trip device for an overcurrent circuit breaker such as a miniature circuit breaker, comprising a tripping armature (1) which actuates a latching mechanism (20) and can be actuated by a coil (3) flowed through by the current to be monitored, with the tripping armature (1) being indirectly actuatable by a magnetic armature (5) which can be moved directly by the coil (3) and which is joined with a tripping armature (1) by at least one elastic coupling member (4) and optionally one or several auxiliary armatures (11), characterized in that the tripping armature (1) is held in its idle position with a predeterminable holding force (F_H) and is made to move abruptly after exceeding said holding force (F_H).
2. A trip device according to claim 1, characterized in that the holding force (F_H) is a force produced in a mechanical manner.
3. A trip device according to claim 2, characterized in that the holding force (F_H) is a static friction force which can be produced by components (8) which are in contact with the tripping armature (1).
4. A trip device according to claim 2, characterized in that the holding force (F_H) can be produced by components (9) acting resiliently on the tripping armature (1) such as a catch spring.
5. A trip device according to claim 1, characterized in that the holding force (F_H) is a magnetic force produced by at least one permanent or electromagnet (13; 14, 25) acting upon the tripping armature (1).
6. A trip device according to one of the claims 1 to 5, characterized in that the holding force (F_H) acting upon the tripping armature (1) is changeable.
7. A trip device according to claim 6, characterized in that the holding force (F_H) can be changed depending on the strength of the current to be monitored.
8. A trip device according to claim 7, characterized in that the holding force (F_H) can be produced by an electromagnet which is flowed through by a current which is directly proportional to the current to be monitored.
9. A trip device according to one of the claims 1 to 8, characterized in that the at least one elastic coupling member (4) is formed by a coil spring.
10. A trip device according to one of the claims 1 to 9, characterized in that the magnetic armature (5) is arranged at least in sections in the interior of the coil (3).
11. A trip device according to claim 10, characterized in that the tripping armature (1) is also arranged in the interior of the coil, with the tripping armature (1) consisting of a non-magnetizable material.
12. A trip device according to claim 11, characterized in that the magnetic armature (5) is arranged as a tubular element which is closed off on one side and that the tripping armature (1) and the at least one coupling member (4) are arranged at least partly within the hollow space formed by the magnetic armature (5).
13. A trip device according to claim 10, 11 or 12, characterized in that the tripping armature (1) comprises a projection which extends through the magnetic armature (5) and extends preferably parallel to the longitudinal axis of the coil (3) and on which the holding force (F_H) acts.
14. The use of a trip device according to one of the preceding claims as a fault-current trip device in a miniature circuit breaker.

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