EP1078381B1 - Bistable magnetic drive for a switch - Google Patents

Abstract

Disclosed is a magnetic drive for an electrical switch, including a linear armature (26) displaceable between two ends positions, a shunt body (27) mounted at a distance from said armature and means (24, 25, 30, 31) for generating a magnetic field. The magnetic field exerts a force on the armature (26) retaining the latter in the end positions. By joining the shunt body (27) with the armature (26), the course of the flow lines of the magnetic field are changed in such a way that the retaining force exerted on the armature (26) is reduced and the latter is displaced to the other end position, optionally by a force exerted externally on the armature (26), and retained in the position by the magnetic field. Disconnection is effected by the shunt body (27), were after being joined with the shunt body (27) the armature (26) is moved from the end position opposite the shunt body (27) to the end position facing the shunt body (26). Fixing means (37-40, 42-45) are especially provided which hold the shunt body (27) in the end position opposite said shunt body and which joins the shunt body with the armature (26) when the electric switch (1) is disconnected requiring little energy/force expenditure.

Description

The invention relates to a bistable magnetic drive for a switch, in particular for an electrical switch, with a linearly displaceable between two end positions in a room, cooperating with at least one movable switching contact anchor, with a substantially on the axis of displacement of the armature and at a distance therefrom arranged, formed of a magnetizable material shunt body, as well as means for generating a magnetic field, on the armature a force holding them in the end positions exerts, wherein the merging of the shunt body with the armature, the course of the flux lines of the magnetic field is changed so that the holding force is reduced to the armature.

Magnetic drives of the affected type are mostly used in the field of electrical switching technology, especially for circuit breakers that turn on rated currents or overcurrents under specified conditions and interrupt and isolate electrical circuits from each other. Since these switches have two stable states, namely an open state in which the electrical insulation of the affected circuits is maintained, and a closed state in which the set nominal current flows continuously and an overcurrent is withstood for a certain time, it is necessary in particular that the underlying drives at the switches also have two stable states, d. H. Retirement homes that require retention.

A bistable magnetic drive for an electrical switch of the type described above is known from DE-OS 196 19 835 , to which reference is made in the present context, known. In this magnetic drive is a linearly displaceable between two end positions, with at least one movable switching contact connected anchor provided, which is kept stable in the end positions under the influence of magnetically generated forces. Further, a ferromagnetic shunt body is provided, wherein the armature and the shunt body are arranged one behind the other in a space between a first and a second stop. The stops are formed as pole faces of magnetic circuits caused by a pair of permanent magnets holding the slidable armature in the two stable end positions. In addition, a pair of electromagnets is provided whose variable magnetic field serves to move the armature between the two stable end positions. In particular, the shunt body serves to invert in the direction and to transmit to the shunt body by applying to the armature the force exerted on the armature by the permanent magnets, possibly with a force exerted on the armature from outside, whereby the shunt body and the shunt Anchor to be moved to its second stable end position and held therein.

The magnetic circuit is thus designed so that the lines of force of the permanent magnets, depending on whether the armature and the shunt body are separated or abut each other, so close outside of the armature and the shunt body that the outgoing of the permanent magnet force in each of the both directions of movement of the armature or the shunt body is directed.

In the known drive, the armature can assume two stable positions in which it rests, on the one hand, on the first stop and, on the other hand, on the bypass body, which in turn rests against the second stop in the second stable position of the armature. It is thus prevented that the armature that drives the movable contact, "stuck" in an intermediate position between the end positions. When the switching of the armature position has been initiated by switching on the electromagnets or the application of the shunt body to the armature, the switching takes place automatically and quickly. Despite the relatively low opening power selected, no stable intermediate position between the two end positions of the armature is possible. H. a once initiated switching process inevitably leads to an opening or closing of the switch.

A special requirement in the case of the switches concerned here is that the most reliable and, in particular, rapid disconnection, particularly in an emergency situation ("emergency stop"), must be ensured. In the known switches therefore technically complex mechanical accessories (eg lever devices) are provided by means of which the armature can be moved to the 'OFF' position of the switch and therefore the elimination is accomplished only with a relatively high energy consumption.

The present invention is therefore an object of the invention to improve a magnetic drive of the type mentioned in that the required when switching off the power switch operated with the drive force and energy consumption is minimized and overall reliability is increased, in particular to the effect that an emergency shutdown can be done as quickly as possible and reliable. At the same time, the technical design of the drive should be as simple as possible in terms of its production, in order to ultimately minimize manufacturing costs. In addition to these requirements, however, should not be waived the use of a shunt body of the type mentioned with the particular advantage of less effort in the movement of the armature.

This object is achieved in a magnetic drive of the type mentioned according to the invention that a lock is provided for the shunt body, by means of which the shunt body in this facing end position durable and from this end position with little energy / effort is solvable. With this lock, the shunt body during the turn-off, especially in the event of an emergency shutdown of the operated electrical switch, with little energy / effort and relatively quickly be merged with the anchor.

According to the invention, therefore, the bypass body is advantageously used when turning off the switch. In particular, the speed of movement of the bypass body is decisive for the switch-off time. However, this requirement is precisely taken into account by the proposed mechanical holding device in that the shunt body can be detached from its holding position and thus also relatively quickly with little energy / effort.

According to a first exemplary embodiment of the invention, the strict safety requirements for trouble-free functioning of switching off a switch operated with the magnetic drive according to the invention, in particular in the event of an emergency stop, are fulfilled by the shunt body being lockable in the end position by means of mechanical holding means. The proposed mechanical holding device for the shunt body is less susceptible to interference, for example, electrical or magnetic holding devices and also in emergency situations, which are often associated with a power failure, still fully functional.

According to a preferred embodiment of the magnetic drive according to the invention, the mechanical holding means are realized by a mechanical lock, by means of which the shunt body facing in the shunt body End position is maintained, wherein acts on the bypass body after a release of the lock, a spring force in the direction of the armature. In this embodiment, therefore, due to, for example, a mechanical compression spring, the shunt body receives a supporting force for movement in the direction of the armature, which counteracts the force caused by the permanent magnet (s) and automatically acts on the shunt body as soon as the mechanical sheath of the shunt body has been removed.

In the mechanical holding means may be provided in particular that a mechanical locking of the bypass body has a connected to the shunt body guide rod which is pivotally connected to a cooperating with a sensing device lever arm.

Alternatively, in the case of the mechanical holding means, a mechanical threshold or barrier can also be provided, by means of which the shunt body is held unstably in the end position facing the shunt body by a small holding force, so that the shunt body can be detached from this end position by overcoming this low force potential and with the anchor is merge.

According to a further embodiment of the Magnetic drive according to the invention can be provided that the shunt body can be locked in the end position by means of magnetic holding means.

Further features, details and advantages of the invention will become apparent from the appended claims and with reference to an embodiment of the magnetic drive according to the invention shown in a drawing.

Fig. 1

einen Mittel- oder Hochspannungs-Leistungsschalter mit einem erfindungsgemäßen linearen magnetischen Antrieb in Seitenansicht, teilweise im Schnitt;

Fig. 2a,b

eine schematische Seitenansicht eines erfindungsgemäßen Magnetantriebs mit jeweils zwei unterschiedliche Positionen aufweisendem Anker und Nebenschlusskörper;

Fig. 3

die in Fig. 2a und 2b gezeigte Ausführungsform des magnetischen Antriebs in schematischer Seitenansicht mit einer detaillierten Darstellung einer erfindungsgemäßen mechanischen Verriegelung für den Nebenschlusskörper;

Fig. 4a-c

drei unterschiedliche Arbeitsphasen des magnetischen Antriebs repräsentierende Seitenansichten entsprechend Fig. 3;

Fig. 5a-e

schematische Seitenansichten des erfindungsgemäßen magnetischen Antriebs während sechs unterschiedlicher Arbeitsphasen und der entsprechenden Magnetfeldlinien.

Show it:

Fig. 1

a medium or high voltage circuit breaker with a linear magnetic drive according to the invention in side view, partially in section;

Fig. 2a, b

a schematic side view of a magnetic drive according to the invention, each with two different positions exhibiting anchor and shunt body;

Fig. 3

the embodiment of the magnetic drive shown in Figure 2a and 2b in a schematic side view with a detailed illustration of a mechanical lock according to the invention for the bypass body.

Fig. 4a-c

three different working phases of the magnetic Drive representing side views corresponding to FIG. 3;

Fig. 5a-e

schematic side views of the magnetic drive according to the invention during six different working phases and the corresponding magnetic field lines.

With reference to Fig. 1, a use of the magnetic drive according to the invention in a medium or high voltage circuit breaker will be explained first. A circuit breaker 1 includes three switch poles 2, 3, 4, each having a switching chamber 5, in which there are a stationary, not shown switch contact and a movable, also not shown switching contact. The switching chamber 3, z. As a vacuum switch, is conventional design. The movable switching contact is connected to a shaft 7, which is mounted longitudinally displaceable under bias of a spring 8 on a shaft 6. In switch-on or closed position of the circuit breaker, the springs 8 of the switch poles 2, 3, 4 are stretched, ie the springs 8 relax when opening the circuit breaker. As a result, the movement of the shaft 7 required for an elimination is assisted by the spring force of the springs 8 or a so-called "opening spring"('44' in FIG. 1). The shaft 6 is rigidly connected to a rod 9, the z. B. via a bolt 10 to the one end of a pivotally mounted Knee lever 11 is articulated, the other end is pivotally connected to a rod 9 displaceable in a housing 12 at a right angle to the rod. The housing 12 carries the switch poles 2, 3, 4, which are arranged in a row.

At one end of the rod 13, the one end of another pivotally mounted in the housing 12 toggle lever 14 is hinged, the other end is pivotally connected to a rod 15 which is in turn connected at its other end with a linear magnetic drive 16 according to the invention.

In the following part, a preferred embodiment of the magnetic drive according to the invention will now be described, wherein identical components shown in the various figures are designated by matching reference numerals.

The linear magnetic drive 16 shown in FIGS. 2 a and 2 b (FIG. 2 a for an open switch 1 and FIG. 2 b for a closed switch) has a yoke 20 of magnetizable material, for example of laminated soft iron sheets, which is rectangular on the outside , The outer shape of the yoke is immaterial to the invention and can be freely selected in the context of all conceivable forms, for example as a cylindrical shape. In the interior of the yoke 20, a recessed space 21 is provided, in which two on each other opposite sides of pole pieces 22, 23 protrude inward. Permanent magnets 24, 25 are arranged on the inner surfaces of the pole shoes. However, the permanent magnets 24, 25 may also be integrally formed, while the space 21 in the amount of the pole pieces ring surrounded. The permanent magnets 24, 25 are facing each other with the same poles and thus form a corresponding pair of magnets.

In the space 21 in the interior of the yoke 20, an armature 26 and a shunt body 27 are arranged one behind the other linearly movable. Both the armature 26 and the shunt body are made of magnetizable material, preferably of magnetizable metal. The movement space for the armature 26 and the bypass body 27 is limited at one end by a first stop 28 and at the other end by a second stop 29. Laterally, the movement space of the armature 26 is also limited by the permanent magnets 24, 25.

In further, provided above the permanent magnets and outside the movement space 21 recesses of the yoke, a coil 30 for opening the switch 1 and a coil 31 for closing the switch 1 are respectively provided. The magnetic field generated by the coil 31 thus enables or causes an armature movement in the direction of the upper stop 29, whereas that generated by means of the coil 30 Magnetic field allows an armature movement in the direction of the bypass body 27 or causes.

The movement space for the armature 26 and the bypass body 27 is bounded at the top by an inserted into the recess of the yoke upper plate 33 and below by a corresponding lower plate 34.

At the anchor further comprises a through hole 35 is provided, into which a bolt, not shown, is inserted, with which the armature 26 is fixed to a through yoke 20, shunt body 27 and armature 26 running shaft 36. About the shaft 36, the movement of the armature 26 is transmitted to the switch assembly shown in Fig. 1, for example. Via the knee joint 14 shown in FIG.

In this embodiment, the bypass body 27 is held in the provided on the lower stop 28 of the lower plate 34 position by means of a locking mechanism. In particular, a guide rod 37 is attached to the shunt body 27, which in turn is pivotally connected to a hinge 38. The joint 38 is held in the position shown by way of a lug 39, which cooperates with a half-shaft 40, in the direction of rotation of the half-shaft 40 shown here, whereby the shunt body 27 is in turn retained on the lower stop 28.

In an alternative embodiment, the shunt body 27 is held by means of a mechanical threshold (not shown here), for example, may be formed as a retaining spring, in which the bypass body 27 can be 'triggered' by overcoming a spring force potential. The person skilled in the art corresponding holding devices from many fields of technology are familiar.

In the situation shown in Fig. 2b, the armature 26 abuts the upper stop 29 of the upper plate 33 and the shunt body 27 is again in abutment with the armature 26. The required movement of the bypass body 27 is first triggered by the fact that by turning the Half-wave 40, the nose 39 is no longer with the upper half-shaft 40 to stop and thus the joint 38 is free to move. Due to the spring force of a compression spring 41 thus the bypass body 27 moves in the direction of the released by the movement of the armature 26 free space until it is in abutment with the armature 26.

In Fig. 3, a preferred embodiment of a locking mechanism according to the invention is shown in detail. In this embodiment, a bolt or a bracket 42 is attached to the half-shaft 40, which is controlled by an externally controllable movement mechanism, here via a push-button 43, for the operation of the Lock performs necessary rotational movement of the half-wave. The pivotable connection between the guide rod 37 and the joint 38 is realized in the present embodiment by a mounted on the guide rod 37 bolt 44 which engages in a provided at one end of the hinge 38 recess 45. The illustrated shape of the continuous slot 45 is essentially predetermined due to the game caused by the rotational movement of the joint.

Various working phases of the magnetic drive according to the invention will be described with reference to FIGS. 4a to 4c.

In Fig. 4a, the armature is in one of the two stable end positions, wherein the operated by the magnetic drive switch 1 is in the "open" ("OFF") position. In this stable end position, both the armature 26 and the shunt body 27 are respectively on stop and on the lower abutment surface 28 of the yoke 20th

In the situation shown in Fig. 4b, the armature 26 has moved due to the total of the permanent magnet 25 and the electromagnet 31 generated by superposition magnetic field upwards and is now at the upper stop surface 29 at. This second stable end position of the armature 26 is characterized in particular in that the armature 26 and the bypass body 27 are separated from each other. This separation is now effected by the locking mechanism shown in FIG. In contrast, the stability of the illustrated end position of the armature 26 is essentially caused by the action of the outgoing from the permanent magnet 25 field. The phenomenology of the underlying magnetic field and its force acting on the armature 26 will be explained in detail below with reference to FIGS. 5a to 5f.

The stable end position shown in Fig. 4b is set by the bypass body 27 back into an unstable state, which corresponds to the situation shown in Fig. 4c. By loosening the lock, the bypass body 27 has moved due to the spring action of the compression spring 41 in the direction of armature 26 and is now in abutment with this. Due to the resulting change in the course of the magnetic flux lines, a force reversal now takes place downwards, whereby the armature 26, together with the shunt body 27, can be moved down again with relatively little effort, which then sets the situation shown in FIG. 4a again in which the armature 26 assumes the other stable end position.

FIGS. 5a to 5e show simplified, partially sectioned side views of the magnetic drive according to the invention already shown in FIGS. 2 to 4.

In particular, the positions of armature 26 and shunt body 27 during five different operating phases of the magnetic drive are shown. To clarify the mode of operation, the magnetic field lines 50 present in the individual work phases are also schematically drawn.

The sub-figure 5a shows the drive in the open position ("OFF") of the circuit breaker. The subfigure 5b shows the situation at the beginning of the movement of the armature 26 in the closed position ("ON") of the circuit breaker. In the sub-figure 5c, the magnetic field distribution is shown during the switch-on, wherein the armature 26 is in a central position on the way to the closed position of the circuit breaker. In the sub-figure 5d, the magnetic field distribution in the closed position ("ON") of the circuit breaker is shown and in the sub-figure 5e, the phase at the beginning of the movement of the armature in the open position ("OFF") of the circuit breaker, the shunt body 27 previously with the armature 26 has been brought into contact.

During the working phases of the magnetic drive shown in the subfigures 5a to 5d, the shunt body is held by the holding device according to the invention (not shown here) at the lower stop, so that the armature 26 - under separation from the shunt body 27 - under Action of the magnetic field 51 to the upper stop 29 can move.

In Fig. 5e, the bypass body 27 moves due to the force of the spring 41 in the direction of the armature 26 and goes to abutment with this after the (not shown here) locking has been solved.

Claims (8)

1. Magnetic drive for a switch, in particular for an electric switch(1), comprising an armature (26) which is linearly displaceable between two end positions in a space (21) and is suitable for cooperating with at least one moveable switch contact, comprising a shunt body (27) which is formed substantially on the displacement axis of the armature (26) from a magnetisable material and is also displaceable along the displacement axis of the armature (26), and comprising means (24, 25, 30, 31), for producing a magnetic field which exerts a force on the armature (26) so as to hold the latter in the end positions (28, 29), the path of the flux lines of the magnetic field being changed by bringing together the shunt body and the armature (26) so that the retaining force on the armature (26) is reduced, characterized by a lock for the shunt body (27) by means of which the shunt body (27) can be held in the end position (28) facing it and can be released from this end position (28) with application of little energy/force.
2. Magnetic drive according to Claim 1, characterized in that the shunt body (27) can be locked in the end position (28) by a mechanical retaining means (37-40, 42-45).
3. Magnetic drive according to Claim 2, characterized in that a mechanical lock (37-40, 42-45) is provided as mechanical retaining means, by means of which the shunt body (27) can be fixed in the end position (28), and in that a spring force (41) acts on the shunt body (27) in the direction of the armature (26) after opening of the lock.
4. Magnetic drive according to Claim 2, characterized in that a mechanical threshold is provided as mechanical retaining means, by means of which the shunt body (27) can be fixed in the end position (28) and can be brought together with the armature (26) with application of little energy/force.
5. Magnetic drive according to Claim 1, characterized in that the shunt body (27) can be locked in the end position (28) by magnetic retaining means.
6. Magnetic drive according to Claim 3, characterized in that the mechanical lock (37-40, 42-45) of the shunt body (27) has a guide rod (37) which is connected to the shunt body (27) and is pivotably connected to a lever arm (38) cooperating with a sensing device.
7. Magnetic drive according to one or more of Claims 1 to 6, characterized in that the electric switch (1) is closed in that end position of the armature (26) which faces away from the shunt body (27) and is open in that end position of the armature (26) which faces the shunt body (27).
8. Magnetic drive according to one or more of Claims 1 to 7, characterized in that the armature (26), the yoke (20) and the upper plate (33) are provided with slots for avoiding eddy currents.

Images