SK176099A3 - Device for triggering an overload circuit breaker - Google Patents

Abstract

A device for triggering an overload circuit breaker, such as a line safety switch, has a triggering armature (11) which actuates a switch latch (18) and can be actuated by a coil (6) through which flows the current to be monitored. The triggering armature (11) is retained in its rest position by a spring (12) and an electromagnet (20) through the coil (7) of which flows the current to be monitored or a current proportional to the current to be monitored. The coil (7) can be short-circuited when a predeterminable current strength is reached.

Description

The invention relates to a trip mechanism for an overcurrent tripping device, such as a line circuit breaker, comprising a trip anchor controlling the circuit breaker lock which is operable by a coil through which the monitored current flows.

BACKGROUND OF THE INVENTION

In the case of overcurrent tripping devices, basically, both fuse-links are used, but they can only be used for a single trip and, on the other hand, can be re-switched and therefore reusable automatic machines. In an electrical device, an overload protection of this kind is normally provided in the supply line before the supply line is divided into a plurality of parallel circuits connected in parallel. In each of these circuits there are provided protective devices, which generally consist of mechanisms for the protection of persons (protective switches FI or similar) and mechanisms for protecting the devices (line protective switches, fuses or the like). These current circuits can optionally be further subdivided into further undercurrent circuits, also protected by protective mechanisms.

With such a wiring structure, the protective devices of the supply line, the current circuit and the undercurrent circuit are often connected in series. If an unacceptable high current is now flowing in the undercurrent circuit, it is necessary to switch off the protective switch assigned only to this undercurrent circuit and thereby separate the undercurrent circuit from the mains, but all the preceding circuit breakers should remain closed. where no fault has occurred, they should remain connected to the network. Only if the resulting overcurrent is so large that it can no longer be disconnected by the undercurrent circuit breaker, does the override switch operate. Such a delayed switch-off of the upstream switch is referred to as selectivity.

Two trigger mechanisms are generally provided in the area of line protective switches. The first trigger mechanism is intended to shut off overcurrents whose magnitude is only slightly greater than the rated current of the device and which operate over a longer period of time. The second trip mechanism, the so-called short-circuit trip mechanism, is usually constructed as a coil through which the monitored current flows, having a movable anchor causing the trip. In order to mimic the delay depending on the heating power and hence the current and time intensities explained above on the fuses, thermal bimetallic strips are used to flow the monitored current, the bimetallic strips deforming analogously to the flux wires directly proportional to the square of intensity current and time, and this deformation allows a time-delayed tripping of the trip mechanism at short-circuit current.

These bimetallic strips are components which must be mechanically precisely positioned on the one hand and additional electrical connections are necessary. All in all, bimetallic tapes thus represent a significant complication in the design of the circuit breakers and thus a deterioration in their functional reliability and manufacture. Another disadvantage of such constructions is that the time delayed shutdown caused by the bimetal elementary remains independent of the magnitude of the monitored current. Thus, even at very high short-circuit currents, which must be disconnected without delay in order to protect the device, the protection device is delayed in operation.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a trigger mechanism of the aforementioned type, which will selectively switch off and which will therefore contain only a few insensitive components of a simpler embodiment compared to the known trigger coil. Furthermore, the trigger mechanism according to the invention should lose its selectivity and achieve its activation without delay if the monitored current reaches a predetermined value.

SUMMARY OF THE INVENTION

This is accomplished by a trip mechanism for an overcurrent tripping device, such as a line circuit breaker, comprising a trip anchor controlling the circuit breaker lock which is operable by a coil through which the monitored current flows, according to the invention. an electromagnet, the coil of which flows the monitored current, or a current proportional to the monitored current, the coil being short-circuiting when the predetermined current intensity is reached.

The actuation of the trigger armature is therefore delayed due to these simple construction measures only until the force exerted by the coil and acting on the trigger armature exceeds the holding force of the electromagnet. In addition, selectivity automatically adjusts to the current intensity of the monitored current, but a short circuit that results in an immediate release of the magnetic hold is suddenly canceled.

According to a further preferred embodiment of the invention, the windings of the outer coil layer can be parts without insulating material, and an electrically conductive bridge is provided, which is brought into contact with these parts when a predetermined current intensity is reached. This makes it possible to save a short-circuit contact connected in parallel to the coil, which would have to be dimensioned relatively large with respect to the expected high currents.

In this connection, according to a further embodiment, the coil can be made to comprise only one winding layer, and not all the windings of this layer are provided with an insulating material. This embodiment allows each coil thread to be short-circuitable, thereby guaranteeing a particularly rapid magnetic field cancellation.

According to a further particularly preferred embodiment of the invention, the electrically conductive bridge is mounted on a short-circuiting anchor, which is displaceable from a rest position to a bridge contact position with parts of the threads not provided with insulating material by the electromagnet.

Therefore, in addition to the existing electromagnet, only one contact component, namely a short-circuit anchor, must be provided. This makes it possible to have a particularly compact and functionally reliable construction. By suitably dimensioning the holding force of the short-circuiting anchor, it is very easy to adjust the value at which the coil is short-circuited.

In this connection, another embodiment of the invention can be used, in that the holding force holding the shorting bolt in its rest position can be effected by a resilient component connected to the shorting bolt and to the trigger mechanism body. Such parts have only small dimensions, so that the overall size of the construction of the trigger mechanism according to the invention increases only insignificantly.

In this case, it may be particularly advantageous if the spring component is formed by a coil spring, preferably a compression spring, since such parts can be manufactured very simply with the force required for this application.

According to a further particularly preferred embodiment of the triggering mechanism according to the invention, the triggering anchor can be operated indirectly by a magnetic anchor movable directly by the coil, the magnetic anchor being preferably connected to the triggering anchor by at least one resilient coupling member or one or more auxiliary anchors.

With this elastic coupling, the magnetic anchor can also be moved before the holding force has been reached, whereby the force acting on the triggering anchor through the coupling member is continuously generated. This embodiment is particularly advantageous for overcurrents with a long rise time, since the magnetic anchor has already traveled a large part of its path here when the switching threshold is reached, but with a stiffer coupling or a direct action of the coil on the starting anchor values first released and would have to go all the way to the switch lock.

According to another embodiment of the invention, the at least one binding spring may be. At the same time, such couplers require good flexibility, which remains for a long time.

In a preferred embodiment, the winding member comprises little space but has a relatively constant

It may be particularly advantageous if the magnetic anchor is arranged at least partially inside the coil. In this embodiment, the magnetic anchor is movable in a precisely predictable manner by the magnetic force of the monitored current.

It may furthermore be advantageous if the trigger armature is arranged inside the coil, the trigger armature being made of a non-magnetic material. This provides a further possibility of reducing the overall size of the trigger mechanism.

According to a further preferred embodiment, the lowering armature may be provided with an extension, preferably arranged parallel to the longitudinal axis of the coil and the magnetic anchor passing therethrough, on which the component of magnetic material is fastened, which is held by an electromagnet. This allows a further geometric reduction of the trigger mechanism according to the invention, which, irrespective of the electromagnet holding the trigger anchor, is dependent only on the size of the coil outside of which there are no moving parts.

Another advantageous embodiment of the invention is that the electromagnet has a Y-shaped yoke, whose transverse rib supports the coil and whose first pair of arms acts through the component on the trigger armature and whose second pair of arms acts on the short-circuit armature. This results in a particularly simple construction of the electromagnet, which nevertheless, in general, still fulfills the requirements imposed on it.

According to a further preferred electromagnet, shorten the longitudinal longitudinal axis of the lowering armature.

In the embodiment of the invention, the axis is arranged perpendicularly to the entire length

According to a short-circuiting short-circuiting embodiment of the invention, there is a lamella. In such a visibly made lower loss of another preferred anchor made of the anchor, it is caused by premagnetization and eddy currents, thereby accelerating the movement of the shorting anchor so that in the end effect the time of actuation of the triggering mechanism can be reduced.

Overview of the drawings

The invention will be further explained by way of example with reference to the accompanying drawings, in which: FIG. 1a, 1b show diagrammatically in front view two possible embodiments of the trigger mechanism according to the invention, FIG. 2a, 2b show in plan view a preferred embodiment of a holding magnet with two different kinds of holding force generation, FIG. 3 shows, in an axonometric view, an embodiment for the holding magnet according to FIG. 2a, 2b, FIG. 4 is a schematic front view of a particularly preferred embodiment of the trigger mechanism according to the invention; and FIG. 5 is a longitudinal section of a line circuit breaker provided with a trigger mechanism according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The triggering mechanism for the overcurrent tripping device, for example the line circuit breaker shown in FIG. 1a and 1b, it comprises a trigger armature 11 which can actuate a switch lock 27 via a pin-shaped extension 27 The switch lock 18 is operable to communicate with one or more movable current-carrying contacts 28 and opens these contacts 28 when actuated by the pin 27 The trigger anchor 11 is arranged inside the coil 6 through which the monitored current flows and can be moved by the magnetic field formed by the coil 6 in the direction of the switch lock 18, as symbolically indicated by the arrow 110, since it is made of magnetic material. The return armature 11 is brought back to its rest position, as indicated by the arrow 120, by a spring 12, the first end of which rests on a fixed part 34, indicated only symbolically, and the other end of which rests on the armature 11 itself.

The trigger arm 11 is in its rest position, in which the pin 27 is spaced from the switch lock 18, held by an electromagnet 20. This electromagnet 20 has a yoke 14 carrying a coil 7, with the monitored current flowing through the coil 7. This is achieved by the series connection of both coils 6 and 7, shown in solid lines. The anchor bolt 11 is provided with an adapter 24 at the end of which a component 13 of magnetic material is fastened. This component 13 forms, with the electromagnet spring 14, a magnetic circuit, by which the above-described holding of the anchor triggering in its rest position is achieved.

The purpose of holding the lower armature 11 in its rest position is thereby to achieve a lowerable start delay. Indeed, triggering can only occur if the force exerted by the coil 6 on the trigger armature 11 is greater than the resultant of the elasticity 12 and the holding force of the electromagnet 20. By the electromagnet 20 itself being energized by the monitored current, the trigger delay, also called selectivity, depending on the current current intensity, so that large current intensity means great selectivity.

Of course, to achieve this selectivity adjustment property, the monitored current need not flow through the coil 7, so it is sufficient if the current 7 is flowing in the coil 7, which is directly proportional to the monitored current. Such a current can be produced, for example, by passing a portion of the monitored current through a parallel resistor 29 connected in parallel to the coil 7, as shown in dotted lines in FIG. Ia. This embodiment makes sense if the electromagnet 20 is constructed in such a way that only a part of the monitored current is sufficient to carry out the described selectivity and a complete current could cause the trigger arm 11 to be held too intensely in its rest position. By changing the parallel resistor 29, selectivity can be influenced in a particularly simple manner.

Although this embodiment entails a relatively greater complexity, it is also within the meaning of the invention that a current separated by a galvanic current from the monitored current but directly proportional to the monitored current can pass through the coil 2.

At particularly high current intensities, a delayed switch-off is no longer desirable and, in the interest of a downstream appliance, such particularly high currents should be switched off as soon as possible. Therefore, it is necessary to eliminate the delay caused by the electromagnet 20 at such high currents, which according to the invention is achieved by a short coil connection

7th

contact 30, wired arranged control

This short connection can be realized in different ways. In FIG. 1 is therefore arranged in parallel to the coil 7. Next to it is a circuit 31 which detects the current intensity, as shown in FIG. When the maximum permissible current intensity is reached, the control circuit 31 closes the switching contact 30, thereby abruptly abolishing the magnetic field passing through the component 13 and the spring 14. Thus, the trigger armature 11 is released and can be operated immediately. switch lock 18.

The embodiment according to FIG. 1b corresponds substantially to the embodiment of FIG. 1a, but the short connection of the coil 7 is made differently here.

In order to make the coil 7, it is necessary to ensure that the coil 7 is provided with only one winding layer in the illustrated embodiments. This is a convenient option, but in. this is by no means a limitation since the coil 7 can have any number of winding layers.

Referring to FIG. 1b all windings have a single coil winding layer 7 of part 71 without insulating material. In addition, an electrically conductive bridge 17 is provided, which can be brought into contact with these parts 71 when a predetermined current intensity is reached.

A further electromagnet consisting of an anchor is provided for the movement of the bridge 17 in the direction of the arrow 170 required for this purpose.

32 connected to the bridge 17 and from the coil 32 acting on the armature 32. This electromagnet is constructed analogously to the embodiment of FIG. 1a by the control circuit 31 as described above. The two embodiments described so far have the disadvantage that a control circuit 31 with associated current measuring devices is required.

In contrast, the embodiments of FIG. 2a and 2b for the movement of the bridge 17, a magnetic field already existing and formed by the coil 7 itself and also representing a measure of the intensity of the monitored current. The bridge 17 is therefore mounted on the shorting anchor 15, the shorting anchor 15 being held in its rest position by a predetermined holding force and displaceable by the electromagnet 20 from this rest position to a position in which the bridge 17 is in contact with the parts 71 without insulating material.

Fixing or holding the short-circuit armature 15 in the rest position is necessary to maintain the start delay created by the electromagnet at low current intensities. The holding force of the short-circuit armature 15 is dimensioned so that, when the current intensity to be delayed is reached, it exceeds the magnetic force generated in the air gap 19 and acting on the short-circuit armature 15. This shortens the short-circuit armature 15, then coils T_ shortly, and the start-up takes place.

The holding force that holds the short-circuit anchor 15 in its rest position may be produced in any manner, for example by frictional forces or the like formed by the parts contacting the short-circuit anchor 15. According to a particularly preferred embodiment shown in FIG. 2a, there is therefore provided a resilient part 16, which is formed by a coil spring made in function of a compression spring. This spring is arranged between the fixed part 21 and the longitudinal extension 151 of the short-circuit armature 15.

In FIG. 2b shows an embodiment corresponding to the embodiment of FIG. 2a, whereby in this embodiment a tension spring 16 mounted on the short-circuit armature 15 and on the fixed part 21 serves as the resilient part 16. The connection of the bridge 17 with the short-circuit anchor 15 is made by means of a contact spring 35.

In FIG. 2a and 2b, a preferred construction of the electromagnet 20 can be clearly discerned. Its yarmol4 has an H-shape, whose transverse rib 140 carries a coil 7, a pair of first arms 141 of which 142 acts through the component 13 and a lowering armature 11, and whose pair of second arms 143 and 144 act on the short-circuit anchor 15.

In FIG. 3, another embodiment of the electromagnet 20 is shown. The pair of first legs 141, 142 is arranged perpendicular to the pair of second legs 143. 144. This arrangement at right angle is not again limiting since the selected angle between the pairs of legs 141, 142, 143 is 144. it is irrelevant to the electrical function and can therefore be of arbitrary value as needed and according to design requirements.

In FIG. 4 shows another embodiment modified from the embodiment of FIG. Ia. A peculiarity of this embodiment is that the trigger armature 11 is not directly controlled by the coil 6, but there is a further armature which will be referred to as the magnetic armature 10. This magnetic armature 10 is controlled by the coil 6, in the direction of the arrow 100 and in connection with the trigger armature 11 via a resilient coupling member 22 formed by a coil spring. The anchor bolt 11 therefore moves by the coil 6 only indirectly in the direction of the arrow 110. This indirect connection can, of course, be expanded by arranging between the magnetic anchor 10 and the anchor bolt 11 auxiliary anchors (not shown) with corresponding other resilient couplers.

To hold the trigger armature 11, the trigger armature 11 is analogous to the embodiment of FIG. 1a, 1b, provided with an extension 24 carrying a magnetic component 13 which extends through a corresponding opening of the magnetic anchor 10 and is arranged approximately parallel to the longitudinal axis of the coil 6.

The triggering of such an arrangement can be divided into two phases, which will now be described. In the first start-up phase, immediately after the overcurrent has occurred, the overcurrent through the coil 6 creates a magnetic field proportional to the current intensity which causes the magnetic anchor to move towards the trigger arm 11. This movement is transmitted to the trigger arm 11 by the resilient coupler. however, it first remains in its rest position due to the holding force exerted by the electromagnet 20. As the magnetic armature 10 continues to deflect, the coupler 22 becomes steadily compressed, thereby decreasing the holding force acting on the trigger arm 11. At this stage of lowering represent a magnetic anchor 10 and a coupling member 22 oscillating system, which is excited by the magnetic force generated by the overcurrent. the time required by the magnetic anchor 10 to compress the coupler 22 to the extent that the holding force is exceeded and the trigger anchor 11 is deflected from its rest position, a time delay occurs, i.e. selectivity of the trigger mechanism according to the invention.

If the overcurrent force exceeds the holding force, the second phase of lowering occurs. In this case, the trigger arm 11 suddenly starts to move, whereby the switch lock 18 is actuated and, as a result, the contacts 28 open. At this start-up phase, the masses of the magnetic armature 10 and the trigger armature 11, in cooperation with the return spring 12, are now an oscillating system. This oscillating system operates as a known magnetic actuation mechanism consisting only of a coil and an anchor, the excitation force being generated by the resultant of the force caused by the current and the holding force.

The lowering, in other words, is not triggered by the overcurrent-controlled armature, but is realized indirectly by the movement of the magnetic armature 10 connected by the resilient coupler 22 to the trigger armature 11 and moved indirectly by the coil 6.

a time delay is created essentially in the first start-up phase. It is determined by the mechanical properties of the oscillating system, the mass of the magnetic anchor 10, the elasticity of the coupler 22 and the stroke of the magnetic anchor 10 and the force exerted by the current. The force exerted by the current is directly proportional to the current intensity and consequently also to the movement of the magnetic armature 10. Therefore, the delay is also proportional to the square of the current intensity, as in the known electrothermal gasification devices mentioned in the introduction.

In FIG. 5 is a longitudinal sectional view of a line circuit breaker provided with a triggering device according to the invention in the closed state. The current path extends from the first terminal 1a through the bimetal 2 and through the flexible braid 2 to the contact bridge 4, thence through the movable contact 28 and the fixed contact 36 to the carrier 5 of this fixed contact 36, further through the coil 6 to the coil 7 and from there to the second terminal lb.

The trigger mechanism of the present invention is in principle made according to FIG. 2a.

The design details that serve to mention and which contribute to the reduction of the overall design size are:

The magnetic anchor 10 as well as the trigger anchor 11 are arranged at rest partially inside the coil 6. In order to prevent the trigger anchor 11 in this arrangement from moving by the magnetic pole of the coil 6, it has to be made of a non-magnetic material such as plastic.

The magnetic anchor 10 is formed as a tubular member closed on one side and a trigger anchor 11 is located at least partially within its cavity 11. In the illustrated embodiment, no resilient coupling member 22 is provided between the magnetic anchor 10 and the trigger anchor 11. If the coupling member 22 is to be provided in this embodiment, it will preferably also be arranged in the cavity of the magnetic anchor 10.

As in the embodiment of FIG. 4, the extension arm 24 extends through the magnetic armature 10 and again carries a component 13 of magnetic material which, in cooperation with the electromagnet 20, causes the armature 11 to be held in its rest position.

The electromagnet 20 has an H-shaped yoke 14 and its longitudinal axis 25 is arranged perpendicular to the longitudinal axis 26 of the trigger armature 11. Thus, the foot overall height of the circuit breaker is substantially reduced, but for purposes of the invention it is also possible to arrange the electromagnet 20 at any angle relative to the longitudinal axis 26 of the lowering armature 11.

The short-circuit armature 15 is preferably made of lamellas to reduce losses due to premagnetization and eddy currents and thereby to guarantee a particularly rapid movement of the short-circuit armature 15.

The switch lock 18 is a conventional and known embodiment. Both the bimetal 27 and the pin 27 provided on the lowering anchor 11 acts on the contact bridge 4. This contact bridge 4 is resiliently biased, so that the slight deflection caused by the two lowering mechanisms is intensified until fully deflected to the off position.

Claims (15)

PATENT REQUIREMENTS overcurrent circuit breakers, comprising (18) a circuit breaker which: A trigger mechanism for devices such as a circuit breaker, a trigger arm (11) controlling the lock, is operable by a coil (6) through which the monitored current flows, characterized in that the trigger arm (11) is held by a spring (12) in its rest position. ) and an electromagnet (20) whose coil (7) flows a monitored current or a current proportional to the monitored current, the coil (7) being short-circuited when a predetermined current intensity is reached. Trigger mechanism according to claim 1, characterized in that the coil windings (7) have parts (71) without insulating material, wherein an electrically conductive bridge (17) is provided which is capable of contacting when a predetermined current intensity is reached. with these parts (71). Trigger mechanism according to claim 2, characterized in that the coil (7) has only one winding layer, all windings of this winding layer having parts (71) without insulating material. Trigger mechanism according to claim 3, characterized in that the electrically conductive bridge (17) is mounted on a short-circuit armature (15) which is movable by the electromagnet (20) from a resting position to a position in which the bridge (17) is in contact. with parts (71) without insulating material, the shorting armature (15) being held in its rest position by a predetermined holding force. Trigger mechanism according to claim 4, characterized in that the holding force holding the short-circuit armature (15) in its rest position can be produced by a resilient member (16) connected to the short-circuit armature (15) and the fixed part (21) of the trigger mechanism. Trigger mechanism according to claim 5, characterized in that the spring part (16) is formed by a coil spring, namely a compression spring. Trigger mechanism according to one of the preceding claims, characterized in that the trigger armature (11) is actuable by a magnetic indirectly actuable coil (6) by the trigger armature (11), in particular by means of at least one resilient coupling member (22) and optionally one or more auxiliary devices. berthed. an anchor (10) which is and is connected to the anchor Trigger mechanism according to claim 7, characterized in that the at least one resilient coupling member (22) is formed by a coil spring. Trigger mechanism according to claim 7 or 8, characterized in that the magnetic armature (10) is arranged at least partially inside the coil (6). A trigger mechanism according to claim 9, characterized in that the trigger armature (11) is also arranged inside the coil (6), wherein the trigger armature (11) is made of a non-magnetic material. Trigger mechanism according to claim 10, characterized in that the magnetic anchor (10) is formed as a tubular part on one side, wherein the trigger anchor (11) and the at least one coupling member (22) are arranged at least partially within the cavity formed in the cavity. a magnetic anchor (10). Trigger mechanism according to claim 9, 10 or 11, characterized in that the trigger armature (11) is provided with an extension (24) arranged mainly parallel to the longitudinal axis of the coil (6) and the magnetic armature (10) passing therethrough. a part (13) of magnetic material is fastened to the adapter (24) and is held by the electromagnet (20). Trigger mechanism according to one of Claims 4 to 12, characterized in that the electromagnet (20) has an H-shaped yoke (14) whose transverse rib (140) carries a coil (7), the pair of first arms (141, 142) acts through the component (13) on the lowering armature (11) and whose pair of second legs (143, 144) acts on the shorting armature (15). Trigger mechanism according to claim 13, characterized in that the longitudinal axis (25) of the electromagnet (20) is arranged perpendicular to the longitudinal axis (26) of the trigger armature (11). Lowering mechanism according to one of Claims 4 to 14, characterized in that the short-circuit anchor (15) is made of slats.