EP2881967B1 - Magnetic trigger for a switching device - Google Patents

Description

The invention relates to a magnetic release for a switching device.

In tripping devices for switching devices, in particular circuit breakers, with electronically controllable triggers magnetic triggers are usually used to trigger a lock chain. The triggering can be done by energizing a coil of the magnetic release whose magnetic field de-energizes the magnetic field of a permanent magnet, so that an anchor held thereby can be pressed by a spring into a release position. Due to the electronic control of the magnetic release is also referred to as electronic or electronically controlled trigger (E-trigger).

The WO03 / 098651A1 describes a magnetic shutter with reduced current flow through a coil for triggering, but still ensures a safe attraction. This is achieved by dimensioning a non-magnetic layer, which is arranged between two permanent magnets, in such a way that, on the one hand, the remaining attractive force is large enough in the switched-on state to ensure reliable attraction of the permanent magnets, in particular also under mechanical shocks Trigger case, the repulsive force of the two permanent magnets is so large that frictional forces and inertia are overcome and an excess of force is present, which is sufficient to trigger a lock chain of a switching device.

The EP 0 051 231 A1 relates to a magnetic release with a fixed and a movable permanent magnet whose magnetic fields overlap to form a total magnetic field. Via the movable permanent magnet, the total magnetic field and thus the tripping sensitivity of the magnetic release can be adjusted. The DE 19 62 562 U also describes a magnetic release with an arrangement of two permanent magnets.

In order to expand the field of application and functionality, switching devices with electric triggers can also be equipped with modules that trigger a tripping when the system is switched on Voltage caused by so-called working (current) trigger (A-trigger) or in case of falling voltage by so-called undervoltage release (U-trigger). An A-trigger is mainly used for remote triggering, for example, if a power interruption should not lead to an automatic shutdown. A U-trigger operates at a too low voltage or a power interruption a triggering device, for example, to prevent the automatic restart of electric motors.

Since the space is limited in the usual switching devices, and the mechanical connection of the E-trigger to the switching drive already requires some space, currently only one additional module, so either an A or a U-trigger can be used in such switching devices.

Object of the present invention is therefore to propose an improved magnetic release for a switching device.

This object is solved by the subject matters of the independent claims. Further embodiments of the invention are the subject of the dependent claims.

One of the present invention, the underlying idea is to integrate the function of a U-trigger in a magnetic release for a switching device. This is inventively achieved in that the magnetic release is designed such that it can be adjusted by an E or A tripping function on a U-trip function. The adjustment is made by adjusting a total magnetic field generated by the superimposed magnetic fields of a first and second permanent magnet, which acts on the armature of the trigger. The total magnetic field may be adjusted for an E or A trip function to hold the armature in a latched position against the pressure of a spring urging the armature into a firing position. For a U-trip function, the total magnetic field can be set to a level that is not sufficient alone to hold the armature in the latched position against the pressure of the spring. In this case, the armature is held in the latched position by energizing a coil to move the armature so that when the voltage across the coil drops, a trip occurs and the U trip function is implemented. The integration according to the invention makes it possible to use the space normally required for an A or U release module for other functions. In addition, the electronic trip control and adjustable trip function of the E-Shutter allow for more flexible use, as various trip functions such as an A- and a U-trip can be integrated together with an E-trigger.

An embodiment of the invention relates to a magnetic trigger for a switching device with a movably mounted armature for triggering a lock chain of the switching device, a spring which exerts a force on the armature to push it to a position for triggering the lock chain of the switching device, a electrical coil which generates a force acting on the armature magnetic field in a tripping function dependent on the armature, which either moves the armature in the triggering position or holds the armature in a locked position against the pressure of the spring, a first and a second permanent magnet whose magnetic fields and an adjusting device for adjusting the total magnetic field generated by superposing the magnetic fields of the first and second permanent magnets on a first or a second strength, wherein the total magnetic field with the first strength is sized to the armature against the force of the spring in the latching position, and the total magnetic field is dimensioned with the second strength such that it alone is insufficient to hold the armature against the force of the spring in the latching position

The first and second permanent magnets may be arranged one behind the other on the axis of the armature and the adjusting device may comprise an adjusting unit for displacing the second permanent magnet.

The first and second permanent magnets may be disposed one behind the other on the axis of the armature, and the adjustment device may comprise a magnetic shield which may be interposed between the first and second permanent magnets.

A further embodiment of the invention relates to a tripping device for a switching device with an electronically controllable trigger having a magnetic trigger with adjustable tripping function according to the invention and as described herein, and an electronic trigger control that controls the electronically controllable trigger depending on a set triggering function. The triggering function can be set, for example electronically via appropriate signals depending on the design of the magnetic release on E, A and / or U-trigger, whereby the trigger control adjusts the magnetic release of the E-trigger to the desired function.

Finally, an embodiment of the invention relates to a switching device, in particular a circuit breaker, with a plurality of switching contacts, a switching drive for opening and closing the switching contacts, and a triggering device according to the invention and as described herein, which is mechanically coupled to the switching drive such that when triggered the Switch contacts can be opened.

Further advantages and possible applications of the present invention will become apparent from the following description in conjunction with the embodiments illustrated in the drawings.

In the description, in the claims, in the abstract and in the drawings, the terms and associated reference numerals used in the list of reference numerals recited below are used.

• Fig. 1 ein Schaltungsdiagramm eines Ausführungsbeispiels einer Auslösevorrichtung für ein Schaltgerät gemäß der Erfindung;
• Fig. 2 eine Explosionsdarstellung eines Ausführungsbeispiels eines Magnetauslösers gemäß der Erfindung;
• Fig. 3 eine Seitenansicht eines schematischen Aufbaus eines Ausführungsbeispiels eine Magnet-Auslösers gemäß der Erfindung;
• Fig. 4 eine Schnittansicht eines weiteren Ausführungsbeispiels eines Magnetauslösers mit einem horizontalen Schieber als Verstelleinheit für den zweiten Permanentmagneten gemäß der Erfindung; und
• Fig. 5 eine Schnittansicht eines weiteren Ausführungsbeispiels eines Magnetauslösers mit einem horizontalen Schieber als Verstelleinheit für den zweiten Permanentmagneten gemäß der Erfindung.

The drawings show in

• Fig. 1 a circuit diagram of an embodiment of a tripping device for a switching device according to the invention;
• Fig. 2 an exploded view of an embodiment of a magnetic release according to the invention;
• Fig. 3 a side view of a schematic structure of an embodiment of a magnetic release according to the invention;
• Fig. 4 a sectional view of another embodiment of a magnetic release with a horizontal slide as adjustment for the second permanent magnet according to the invention; and
• Fig. 5 a sectional view of another embodiment of a magnetic release with a horizontal slider as adjusting unit for the second permanent magnet according to the invention.

In the following description, identical, functionally identical and functionally connected elements may be provided with the same reference numerals. Absolute values are given below by way of example only and are not to be construed as limiting the invention.

Fig. 1 shows the diagram of a tripping device according to the invention with an E-trigger 10 and a microcontroller 14 for controlling the E-trigger 10 via an NPN transistor 32, the load path between a supply voltage 34 and a supply voltage terminal of the E-trigger 10 is connected. Microcontroller 14 and E-trigger 10 are further connected to a reference potential 36.

The microcontroller 14 is configured by a firmware for driving the e-trigger 10. In principle, the microcontroller 14 controls the E-trigger 10 via the transistor 32 so that it triggers at a state defined according to the E-trigger function. Additional trip functions can be provided via an A-trigger input 38 and a U-trigger input 40 are set on the microcontroller 14. The microcontroller 14 implements an electronic trigger control for the E-trigger, with which the E-trigger can also be operated as U or A trigger. The electronic trip control 14 may be housed in a separate module that may be coupled to switchgear having an e-trigger suitable for actuation by the electronic trip control 14.

The E-trigger 10 has the in Fig. 2 an armature 16 of the magnetic release 12 is pressed against a spring 20 on a holder 24, behind which a first permanent magnet 18 is disposed, by the magnetic field, the spring 20 below mechanical tension and the armature 16 can be held in a latching position. To release the stored energy in the tensioned spring 20, the magnetic field of the permanent magnet 18 can be de-energized by an electrical coil 22 to redirect it via an air gap to the housing 30 and the holder 24. Due to the thus weakened magnetic field of the permanent magnet 18, which pulls the armature 16 towards the holder 24, the force acting on the armature 16 of the spring 20 is stronger and can push it away from the holder 24, so that one end of the armature 16 from the housing 30 is pushed out and can cause a release of a lock chain of a switching device. The de-excitation of the magnetic field of the permanent magnet 18 is electronically controlled by the microcontroller 14, which energizes the coil 22 for an electronically controlled triggering by driving the transistor 32 accordingly.

According to the invention, the triggering function of the E-trigger 10 can be adjusted from the E-trigger function described above via an adjustment unit 21 to a U-trigger function. The adjusting unit 21 moves a second permanent magnet 19, which is arranged on the axis 17 of the armature 16 behind the first permanent magnet 18, from a first position to a second position, as shown in FIG Fig. 3 is shown schematically. The magnetic field of the second permanent magnet 19 is polarized opposite to the magnetic field of the first permanent magnet 18.

In the first position of the second permanent magnet 19, the air gap L between the first and second permanent magnets 18 and 19 is so large that the total magnetic field generated from the superposition of the magnetic fields of the two permanent magnets 18 and 19 a has first strength, which corresponds approximately to the strength of the magnetic field of the first permanent magnet 18 and is dimensioned such that the armature 16 is held against the force of the spring 20 in the latching position as described above.

In the second position, the second permanent magnet 19 is brought so close to the first permanent magnet 18 that its oppositely poled magnetic field attenuates the magnetic field of the first permanent magnet 18 so strongly that the total magnetic field thus generated has a second, low strength to the armature 16 against to keep the force of the spring 20 in the latching position. To still hold the armature 16 in the latching position, the electrical coil 22 is controlled by the transistor 32 controlled by the microcontroller 14 so that it generates a magnetic field that moves the armature 16 in the latching position and stops there. The armature 16 is held in the latching position as long as the electrical coil 22 is energized via the transistor 32. If a signal is present at the U trigger input 40 in order to initiate an undervoltage triggering, the microcontroller 14 switches off the energization of the electrical coil 22 via the transistor 32 so that the armature 16 is brought into a triggering position by the spring 20.

• Links oben ist der Auslöser 12 im Betriebszustand A-E-Auslöser und im nicht ausgelösten Zustand gezeigt, wobei die Spule 22 nicht bestromt ist. Der erste Permanentmagnet 18 zieht den Anker 16 an sich heran. Durch den Schieber 21 ist der zweite Permanentmagnet 19 soweit vom ersten Permanentmagneten 18 entfernt angeordnet, dass sein Magnetfeld keinen Einfluss auf das Magnetfeld des ersten Permanentmagneten 18 hat.

Fig. 4 shows a sectional view of a magnetic release 12 with a horizontal slide 21 as adjusting unit for the second permanent magnet 19. In Fig. 4 four different operating and adjustment states of the magnetic release 12 are shown, which are explained below:

• Upper left, the trigger 12 is shown in the operating state AE trigger and in the untripped state, the coil 22 is not energized. The first permanent magnet 18 attracts the armature 16 to itself. By the slider 21, the second permanent magnet 19 is arranged far away from the first permanent magnet 18 that its magnetic field has no influence on the magnetic field of the first permanent magnet 18.

Lower left, the shutter 12 is again shown in the operating state AE shutter and in the tripped state, the coil 22 is energized so that their magnetic field, the magnetic field of the first permanent magnet 18 so far attenuated that the armature 16 by the spring from the housing 30 partially as far as can be expressed that a lock chain of a switching device can be triggered. By the slider 21 is the second permanent magnet 19 so far away from the first permanent magnet 18 arranged that its magnetic field has no influence on the magnetic field of the first permanent magnet 18.

Top right, the trigger 12 is shown in the operating state A-E-U-trigger and in the untripped state, the coil 22 is energized. The slide 21 is now pressed into the magnetic release 12 so far that the second permanent magnet 19 is located just behind the first permanent magnet 18 and its magnetic field attenuates the magnetic field of the first permanent magnet 18. The coil 22 is now energized so that its magnetic field holds the armature 16 in the housing 30. If the current drops through the coil 22, the armature 16 by the spring from the housing 30 can be partially pushed out so far that a lock chain of a switching device can be triggered (U-trigger function).

Lower right, the trigger 12 is shown in the operating state A-E-U trigger and in the tripped state, the coil 22 is de-energized. The slider 21 is pushed back into the magnetic release 12 so far that the second permanent magnet 19 is located just behind the first permanent magnet 18 and its magnetic field attenuates the magnetic field of the first permanent magnet 18. The armature 16 is partially pushed out by the spring from the housing 30 so far that a lock chain of a switching device can be triggered (U-trigger function).

Fig. 5 shows a sectional view of a magnetic release 12 with a vertical slide 21 as adjusting unit for the second permanent magnet 19. In Fig. 5 again four different operating and adjustment states of the magnetic release 12 are shown, the in Fig. 4 shown operating and setting states of the magnetic release 12, so that the corresponding descriptions to Fig. 4 also for Fig. 5 be valid

Instead of an adjusting unit, which shifts the second permanent magnet 19, a magnetic shield for adjusting the total magnetic field can be used, which can be introduced between the first and second permanent magnets 18 and 19, respectively. For example, the magnetic shield between the first and second permanent magnets 18 and 19 are inserted when an E-trigger function is to be set. The inserted magnetic shield causes the total magnetic field acting on the armature 16 to have the first strength. When the magnetic shield between the two permanent magnets 18 and 19 is taken out, The magnetic fields of the permanent magnets 18 and 19 overlap to form a total magnetic field with the second strength.

reference numeral

10

E-timer

12

magnetic release

14

microcontroller

16

anchor

17

armature axis

18

first permanent magnet

19

second permanent magnet

20

feather

21

Adjustment unit for the second permanent magnet

22

electric coil

24

Bracket and shunt

26

baseplate

28

compensation ring

30

Housing and shunt

32

npn transistor

34

supply voltage

36

reference potential

38

A trigger input

40

U-trigger input

Claims (5)

1. Magnetic trigger (12) with an adjustable trigger function for a switching device with a movably supported anchor (16),
   a spring (20) which exerts a force on the anchor, and
   a first and a second permanent magnet (18, 19), the magnetic fields of which have opposite polarities,
   characterised by
   an electrical coil (22), which in connection with energisation dependent on a trigger function produces a magnetic field acting on the anchor, which either moves the anchor into the trigger position or holds the anchor in an locked position against the pressure of the spring and
   an adjusting device (21) for setting the total magnetic field, produced through superposition of the magnetic fields of the first and the second permanent magnet, to a first or a second strength, wherein the total magnetic field with the first strength is dimensioned so as to hold the anchor in the locked position against the force of the spring, and the total magnetic field of the second strength is dimensioned so that by itself it is not sufficient to hold the anchor in the locked position against the force of the spring.
2. Magnetic trigger according to claim 1, characterised in that the first and second permanent magnet (18, 19) are arranged behind each other on the axis (17) of the anchor, and the adjusting device has an adjusting unit (21) for displacing the second permanent magnet.
3. Magnetic trigger according to claim 1 or 2 characterised in that the first and the second permanent magnet (18, 19) are arranged behind each other on the axis (17) of the anchor and the adjusting device has a magnetic shielding which can be inserted between the first and the second permanent magnet.
4. Trigger device for switching device with

   - an electronically controllable trigger (10) comprising a magnetic trigger (12) with an adustable trigger function according to any one of the preceding claims and

   - an electronic trigger control (14) which controls the electronically controllable trigger in dependence on a set trigger function.
5. Switching device, more particularly power switch, with

   - several switching contacts,

   - a switching actuator for opening and closing the switching contacts, and

   - a trigger device according to claim 4 which is mechanically connected to the switching actuator in such a way that in the event of triggering the switch contacts can be opened.

Images