DE202011051972U1 - Circuit arrangement for driving a switching device - Google Patents

Abstract

Circuit arrangement for controlling a switching device, which has a first switching position and a second switching position and can be switched between the first switching position and the second switching position, - with at least one electromagnetic actuating device for generating an actuating force for switching the switching device between the first switching position and the second switching position and - A control circuit for controlling the electromagnetic actuating device, characterized in that the control circuit (3) has a converter (W), an intermediate circuit (ZK) connected to the converter (W) and a switching stage (SS) connected to the actuating device (ZM1, ZM2). The converter (W) is designed to convert an intermediate circuit voltage (UZK) from a control voltage (U duration) applied to the converter (W) to the intermediate circuit (ZK) to generate the actuating force (ZM1, ZM2) (F) is supplied.

Description

The invention relates to a circuit arrangement for driving a switching device.

Such a circuit arrangement is used to control a switching device having a first switching position in which the contacts of the switching device are not closed and the switching device is thus opened, and a second switching position in which the contacts of the switching device are connected to each other and the switching device thus turned on is, and can be switched between the first switching position and the second switching position. The circuit arrangement comprises an electromagnetic actuating device for generating a setting force for switching the switching device and a drive circuit for actuating the actuating device. The actuating device is used for switching the switching device between the first switching position and the second switching position and generates, driven by the drive circuit, the required actuating force.

Such a circuit arrangement can be used, for example, as a battery protection switch for connecting a battery to a vehicle electrical system of a vehicle, for example a rail vehicle. In such battery circuit breakers conventional switching devices with an electromagnetic actuator z. B. used in the form of a pull magnet, which have stable switching positions (on / off) and thus can be switched in a bistable manner between the two switching positions. Such switching devices need only in the tightening and breaking moment (electrical) energy to remain in the currently set switching position, in contrast to monostable switching devices that automatically switch back from a deflected position to the starting position after interrupting the power supply.

Battery circuit breakers of this type are used to connect a battery to a vehicle electrical system or to disconnect from the electrical system when needed. In this respect, such battery protection switches fulfill a fuse and switch function for protecting a battery circuit or a battery.

For switching the switching device by means of the actuating device, a control voltage, for example the battery voltage, is conventionally switched to the actuating device designed as a pull magnet, for example, in order to directly excite the actuating device for generating the actuating force and to switch the switching device by means of the actuating force. The switching device is then switched via the actuating device, the actuating device and / or the switching device generally having mechanical armatures or levers which bring about a closing or opening of the switching contacts of the switching device. In order to avoid a current consumption of the switching device for holding in the currently occupied switching position, the switching positions of the switching device are mechanically fixed.

Because in such a switching device, the available control voltage directly to the actuator, for. As a pull magnet is switched, the force generated by the actuating force is usually not the force-displacement characteristics of the switching device, so the course of the required force on the travel adjusted.

In addition, problems may arise because, for example, in the case of rail vehicles, the voltage range of the voltage available at a battery during operation may be great (eg 75 V to 150 V). This can result in that in a lower voltage range of the battery, the control voltage is insufficient to ensure switching of the switching device. At the same time, the control voltage can be so high in an upper voltage range of the battery, so that too great a force is provided which leads to a bouncing of the switching device when reaching a switching position and thus the desired switching position is not taken safely.

The object of the present invention is to provide a circuit arrangement for the switchable connection of a battery to a vehicle electrical system of a vehicle, which enables a safe and mechanically gentle operation of the switching device over a large range of an available control voltage.

This object is achieved by an article having the features of claim 1.

Accordingly, it is provided that the drive circuit has a converter, an intermediate circuit connected to the converter and a switching stage connected to the actuating device, wherein the converter is designed to generate from a voltage applied to the converter control voltage to the intermediate circuit an intermediate circuit voltage, via the Switching stage is supplied in pulsed manner to the actuating device for generating the actuating force.

The intermediate circuit voltage provided via the converter can advantageously be approximately constant. The control voltage supplied via the switching stage in a pulsed manner to the actuating device can then generate a setting force on the actuating device, which can be transmitted via the actuating path of the actuator Actuator is variable and corresponds to a predetermined force-displacement characteristic.

The idea of the present invention is not to feed the control voltage directly to the actuating device via the drive circuit, but first to convert the control voltage into a (constant) DC link voltage via a converter and then to supply it to the actuating device via a switching stage in a pulsed manner , About the converter is achieved so that regardless of the actual available control voltage always the same DC link voltage is generated. Regardless of whether the control voltage is currently in a lower voltage range or an upper voltage range, the DC link voltage is (approximately) constant. The DC link voltage is then supplied in a pulsed manner in the manner of a pulse width modulation for generating a variable over the travel variable actuating force of the actuator, so that the mean value of the voltage across the actuating variable variable via the travel, thus the current consumption of the actuator also variable and the force of a desired force Path characteristic is adjusted.

Characterized in that the actuating force can be variably adjusted by the pulsed control of the actuator, the force of the force-displacement characteristic of the switching device can be adjusted. This ensures a mechanically gentle operation of the switching device with a mechanically low load of the components to be moved.

In addition, by converting the control voltage to the intermediate circuit voltage and the pulsed control of the actuating device when supplying the intermediate circuit voltage to the actuator safe operation in a wide voltage range of the control voltage can be ensured. Both at a low control voltage (in the lower voltage range) and at a high control voltage (in the upper voltage range), switching between the switch positions takes place reliably.

The first switching position advantageously corresponds to a switch-off position of the switching device, ie a position of the switching device in which the switching contacts of the switching device are not in communication and the switching device is thus opened. In contrast, the second switching position corresponds to a switch-on of the switching device in which the contacts of the switching device abut each other and the switching device is thus closed to connect a battery to a vehicle electrical system. The force-displacement characteristic can in this case be such that the actuating force at the beginning of the travel from the first switching position corresponds to an initial force. To transfer the switching device from the first switching position to the second switching position, the actuating device is then controlled such that from a pressure point, the actuating force increases with the travel up to a maximum force, wherein the maximum force is reached at a maximum point on the travel. Behind this maximum point, the actuating force drops with the travel and, in the second shift position, corresponds to an end force that is less than the maximum force and greater than the initial force. This results in a variable over the travel force, which is adapted to the force-travel characteristics of the Einschaltmechanismus a battery circuit breaker advantageously, so that at each location on the travel just the force is provided, which is required for switching the switching device , An excessive mechanical load due to an increased force is avoided in this way.

The drive circuit may comprise, for example, a time relay and a power relay, wherein the triggerable time relay is designed to control the power relay so that regardless of the duration of a trigger applied to the timing relay, the power relay switches the control voltage for a predetermined on-time to the converter. The predetermined switch-on time is in this case selected to be greater than the (maximum) switching time for transferring the switching device from the first switch position to the second switch position, so that independent of the prevailing ambient conditions via the time relay takes place a sufficiently long time control of the electromagnetic actuator.

The background here is that the electromagnetic actuator on the one hand must be controlled at least as long until z. B. the armature of a pull magnet is in the end position. On the other hand, too long a control of the electromagnetic actuator should be omitted in order to avoid a (thermal) overload of the actuator. This is ensured by the fact that the time relay always drives the power relay only for a predetermined switch-on time in order to switch the control voltage to the converter via the power relay for this predetermined switch-on time. The converter then converts the control voltage into the intermediate circuit voltage, and after a time delay after actuation of the time relay, the switching stage controls the actuator in a pulsed manner.

The time relay can be operated manually, for example via a button or in a remote-controlled manner.

In an advantageous embodiment, the converter is designed as a boost converter with a boost converter inductor, a pulse width modulator and a first semiconductor switch. The boost converter inductor is connected on the one hand to the control voltage and on the other hand via the first semiconductor switch to a ground terminal and via a diode to the DC link. In this case, the pulse width modulator is designed to switch the first semiconductor switch in a pulsed manner to generate the intermediate circuit voltage at the intermediate circuit and, via the first semiconductor switch, to connect the boost converter choke to the ground terminal in a pulsed manner. The first semiconductor switch is in this case driven in such a way that a current is fed via the diode in the desired manner into the intermediate circuit and thereby the desired intermediate circuit voltage is set at the intermediate circuit.

The intermediate circuit contains in known manner a link capacitor, which is fed via the converter and is connected via the switching stage with the actuating device. In this case, the intermediate circuit voltage is switched to the actuating device in a pulsed manner via the switching stage, so that a time-variable mean value of the voltage and, accordingly, a temporally variable current for generating a variable actuating force via the actuating path are set on the actuating device.

The switching stage may, for example, have a pulse sequence circuit and a second semiconductor switch. The pulse sequence circuit is in this case designed to generate a pulse train for switching the second semiconductor switch to switch by pulsed driving the semiconductor switch the DC link in a pulsed manner to the actuator and thus set a time-variable current to the actuator.

The pulse width modulator and / or the pulse sequence can be implemented as separate electronic components or by a microcontroller, which controls in a suitable manner the (first) semiconductor switch of the converter and / or the (second) semiconductor switch of the switching stage.

As already indicated, the actuating device is advantageously formed by a pull magnet in which, as a result of a current flow, an armature is moved in an electromagnetic manner or a lever is adjusted. In principle, however, other embodiments of actuators for generating a force are conceivable.

In a simple embodiment, the drive circuit is formed with a converter and a switching stage to control an actuator. It is also conceivable to equip the drive circuit for driving two or more actuators with two or more transducers and two or more switching stages, so that a plurality of switching devices can be operated via a single drive circuit.

By temporally limited activation of the actuating device by means of the described time relay can be ensured in the present case that the actuating device, in particular when trained as a pull magnet, is not operated for too long an operating time. In addition, to provide additional protection against overload, a fuse may be provided as part of the drive circuit which interrupts current flow through the actuator when overload of the actuator is detected. The fuse can trigger, for example, at an increased current flow. It is also possible that the fuse is thermally coupled to a (power) resistor to absorb a thermal overload and to interrupt a current flow as a result of thermal overload.

The idea underlying the invention will be explained in more detail with reference to the embodiments illustrated in the figures. Show it:

1 a schematic view of a circuit arrangement for switchably connecting a battery to a vehicle electrical system of a vehicle;

2 a circuit diagram of a drive circuit of the circuit arrangement; and

3 a diagrammatic representation of a force-displacement characteristic of a switching device of the circuit arrangement.

1 shows a schematic circuit diagram of a circuit arrangement with a switching device 2 and a drive circuit 3 that serves a battery 1 switchable to an electrical system B to connect.

The switching device 2 is this with the positive potential (+) of the battery 1 and connected to the electrical system B. The electrical system B is connected to the negative potential MB (also referred to as "negative battery"). The drive circuit 3 is with the positive potential of the battery 1 which has a control voltage U _duration for the drive circuit 3 providing, via a switch S having a turn-on voltage U _A and the minus potential of the battery MB 1 connected.

A circuit arrangement of the type described here can be used, for example, in a vehicle, in particular in a rail vehicle. The switching device 2 serves in this context to provide a safety function and a switching function to the battery 1 optionally to connect to the electrical system B or separate from the electrical system B and in this way, if necessary, the battery circuit with the battery contained therein 1 to protect. Such circuits are also referred to as battery protection switch accordingly.

The switching device 2 is bistable and accordingly has two stable switching positions, corresponding to an open position in which the battery 1 disconnected from the electrical system B, and a closed position in which the battery 1 connected to the electrical system B is connected.

Because the switching device 2 Having stable switching positions and thus the switching positions are secured, for example, by mechanical means, no (electrical) energy is required to the switching device 2 to keep in one or the other switching position. Will the switching device 2 For example, switched to the closed position, the switching device remains 2 in this switching position, even if the power supply is subsequently interrupted. This has the advantage that the switching device 2 and an actuator of the drive circuit 3 after switching no current absorbs and thus a constant power supply to hold the switching device 2 is not required in the currently occupied switching position, so that even with a longer-term shutdown of the vehicle there is no unloading of the switching device 2 feeding battery comes.

The switching device 2 is via the drive circuit 3 driven. At an in 2 in a circuit diagram schematically illustrated drive circuit 3 two actuators in the form of traction magnets ZM1, ZM2 are controlled by two (separate) control stages. The pull magnets ZM1, ZM2 with a power consumption of z. B. each 300 W are each with a switching device 2 in conjunction and act on the respective associated switching device 2 for switching between the switching positions. The control stages of the drive circuit 3 for driving the tension magnets ZM1, ZM2 are functionally identical, so that below the operation of the drive circuit 3 to be described with regard to only one of these Ansteuerstufen.

The drive circuit 3 has a timing relay ZR, a power relay K and in each one Zerm1, ZM2 ZM2 drive stage associated with a converter W, a DC link ZK and a switching circuit SS, via which in each case a pull magnet ZM1, ZM2 can be controlled. The time relay ZR serves here to control the power relay K over a predetermined switch-on time t by a push button S (manually, remotely controlled or automatically triggered if necessary), connected via a trigger voltage U _Ein to the timing relay ZR and thereby the power relay K for the predetermined switch-on time t for switching a control voltage U _duration to the converter W is controlled.

The timing relay ZR is designed as a monostable time switch and switches back to the predetermined switch-on time t in its initial position in which the power relay K switches off and thus the control voltage U _duration does not reach the transducer W.

If the power relay K (for the predetermined switch-on time t) is switched, then the control voltage U _duration via an input filter 31 the converter W supplied. The transducer W is designed as a boost converter (also referred to as up-converter) and has a boost converter inductor 32 , a pulse width modulator 33 , a driver 34 and a semiconductor switch 35 on. The boost converter choke 32 is over the semiconductor switch 35 connected to a ground terminal GRD and also coupled via a diode D1 to the DC link ZK. The pulse width modulator 33 serves to generate a pulse width signal for driving the semiconductor switch 35 and acts on the driver 34 a, according to a circuit breaker realizing semiconductor switch 35 controls.

By driving the semiconductor switch 35 over the pulse width modulator 33 becomes the boost converter choke 32 connected in a pulsed manner to the ground terminal GRD. By suitable control is in this case from the on the power relay K and the input filter 31 to the boost converter choke 32 applied control voltage U _duration a (constant) DC link voltage U _ZK to a _{DC link} capacitor 36 the intermediate circuit ZK formed, this intermediate circuit voltage U _ZK is substantially constant and may be greater than the control voltage U _duration .

In this way, the transducer W generates at the DC link capacitor 36 the intermediate circuit voltage U ZK from the control _period an intermediate circuit voltage U _ZK in the intermediate circuit capacitor 36 which is substantially independent of the actual value of the control voltage U _duration . The control voltage U _duration can be, for example, via the battery 1 be made available and in a voltage range between 75 V and 150 V move. The intermediate circuit _voltage U _ZK can for example, have a constant value of 127V.

Via the switching stage SS, the intermediate circuit voltage U _{ZK is} supplied in a pulsed manner to the actuating device in the form of the traction magnet ZM1, ZM2. The pull magnet ZM1, ZM2 is this on the one hand with the DC link voltage potential and on the other hand via a semiconductor switch 39 the switching stage SS connected to the ground terminal GRD. The switching stage SS has a pulse sequence 37 for generating a pulse train, a driver 38 and the semiconductor switch 39 on, wherein the pulse sequence circuit 37 a pulse train to the driver 38 and above the semiconductor switch 39 for pulsed driving of the pull magnet ZM1, ZM2 drives.

The semiconductor switches 35 . 39 may be realized, for example, by a MOSFET transistor circuit.

About the semiconductor switch 39 the pull magnet ZM1, ZM2 is driven in a pulsed manner, thereby supplying the intermediate circuit voltage U _ZK in a pulsed manner to the pull magnet ZM1, ZM2. In this way, a time-variable voltage mean value and correspondingly a time-variable current can be set on the tension magnet ZM1, ZM2, which results from the mean value of the pulsed intermediate circuit voltage U _ZK .

The from the pulse sequence 37 generated pulse sequence is such that over the turn-on time t of the timing relay ZR, a current through the pull magnet ZM1, ZM2 is set to the pull magnet ZM1, ZM2 a force F (see 3 ) generates the force-displacement characteristic of the switching device 2 is adjusted.

How out 3 can be seen, the force-displacement characteristic is such that when transferring the switching device 2 from a position corresponding to the first open position s ₀ in a closed position corresponding second switching position s _End on the travel s first a comparatively low initial force F _{Anf is} required, from a pressure point s ₁ to a maximum point s ₂ to a maximum force F _max increases and decreases after the maximum point of s ₂ to the second shift position to a final force F s _{End End.} According to the curve of this force-displacement characteristic, the actuating force F is generated on the tension magnet ZM1, ZM2, so that the force F of the force-displacement characteristic of the switching device 2 is adjusted.

By adjusting the force F to the force-displacement characteristics of the switching device 2 becomes a mechanically gentle operation of the switching device 2 guaranteed. In particular, an excessive force F is avoided, which in a striking of mechanically actuated components to wear or even damage to the switching device 2 could lead.

In addition, by adjusting the force F to the force-displacement characteristics of the switching device 2 ensures that regardless of the actual available control voltage U _duration reliable switching of the switching device 2 he follows. In particular, by the conversion of the control voltage U _duration in the intermediate circuit voltage U _ZK and the adjustment of the force F to the force-displacement characteristic of the switching device 2 over the entire voltage range of the control voltage U _duration ensures that enough energy to switch the switching device 2 is present and also a bouncing of mechanically operated components of the switching device 2 is excluded.

For the specific operation of the drive circuit 3 It can be provided that initially via the converter W upon actuation of the timing relay ZR the intermediate circuit voltage U _ZK to the desired constant value of z. B. 127 V is built. If the intermediate circuit _voltage U _{ZK is set} in the desired manner, the semiconductor switch can, with a time offset 39 via a suitable pulse sequence by means of the pulse sequence circuit 37 be driven to produce a force with a desired curve on the pull magnet ZM1, ZM2.

For the formation of the pulse train, the pulse sequence can 37 For example, generate a pulse width modulated signal with a constant fundamental frequency of 1 kHz.

The pull magnets ZM1, ZM2, which are used as actuators for the control of switchgear 2 serve, are designed for a short-time operation and are correspondingly on the timing relay ZR of the drive circuit 3 only controlled by a short, predetermined switch-on time t. The switch-on time t of the time relay ZR is to be dimensioned so that even with changing environmental conditions, the switch-on time t is greater than the switching time required to switch the switching device 2 , ie for transferring the switching device 2 from the one switching position to the other switching position, is required.

The drive circuit 3 has fuses F1, F2, which are the input filter 31 upstream. These fuses F1, F2 serve in (thermal) overload of the drive circuit 3 and the pull magnet ZM1, ZM2 to interrupt a current flow and in this way in particular to protect the pull magnet ZM1, ZM2.

The fuse F1 is formed here as a thermal fuse and thermally coupled to a power resistor R1, so that detected via the power resistor R1, a thermal overload and correspondingly a current flow can be interrupted. The size of the power resistor R1 of the thermal fuse F1 is advantageously to be selected such that the power resistor R1 has a thermally equivalent behavior to the associated tension magnet ZM1, ZM2.

The fuse F2 interrupts the flow of current when an overcurrent occurs, for example due to a short circuit.

If, in the event of a fault, the permissible operating time of the traction magnet ZM1, ZM2 is exceeded, at least one of the fuses F1, F2 triggers and in this way prevents a (thermal) overload of the traction magnets ZM1, ZM2.

The diodes D2 of the control stages are provided as polarity reversal protection. The diodes D4 are intended to stabilize an internal control voltage.

The pulse width modulator 33 of the converter D and the pulse sequence circuit 37 The switching circuit SS can be realized for example by a microcontroller, which is used to control and form the desired pulse sequences via the driver 34 . 38 the associated semiconductor switches 35 . 39 controls.

With the use of a microcontroller, a further development is conceivable to generate a detection of the switching operations for lifetime prognosis for detecting a possible maintenance requirement. Thus, by means of the microcontroller, the switching operations can be counted to produce a signal indicating a maintenance of the switching device after a predetermined number of switching operations (eg, after 20,000 switching operations) 2 and / or the drive circuit 3 should be made.

The idea underlying the invention is not limited to the above-described embodiments, but can also be realized in completely different types of embodiments. In particular, a circuit arrangement of the type described here is not limited to use in rail vehicles, but can also be found in motor vehicles and in principle in other contexts outside of vehicles as a circuit breaker use.

LIST OF REFERENCE NUMBERS

1

battery

2

switchgear

3

drive circuit

31

input filter

32

Up converter inductor

33

Pulse width modulator

34

Driver for semiconductor switches

35

Semiconductor switches

36

Link capacitor

37

Pulse train circuit

38

Driver for semiconductor switches

39

Semiconductor switches

+/-

battery terminal

B

board network

F

force

^F Anf

initial force

F _End

final force

F _max

maximum strength

F1

Thermal fuse

F2

fuse

K

power relay

MB

negative potential

R1

resistance

s

Travel Range

s ₀

First shift position

s ₁

pressure point

s ₂

maximum point

s _end

Second switch position

S

saster

SS

switching stage

t

on time

U _duration

control voltage

U _A

trigger voltage

U _ZK

Intermediate circuit voltage

W

converter

ZK

DC

ZM1, ZM2

pull magnet

ZR

time Relays

Claims (14)

Circuit arrangement for driving a switching device having a first switching position and a second switching position and is switchable between the first switching position and the second switching position, - with at least one electromagnetic actuator for generating a force for switching the switching device between the first switching position and the second switching position and - A drive circuit for driving the electromagnetic actuator, characterized in that the drive circuit ( 3 ) comprises a transducer (W), an intermediate circuit (ZK) connected to the transducer (W), and a switching circuit (SS) connected to the actuator (ZM1, ZM2), the transducer (W) being designed to turn off a control voltage (U _duration ) applied to the converter (W) generates an intermediate circuit voltage (U ZK) on the intermediate circuit ( _ZK ) which is pulsed via the switching stage (SS) to the actuating device (ZM1, ZM2) for generating the actuating force (Z) F) is supplied. Circuit arrangement according to claim 1, characterized in that the intermediate circuit voltage (U _ZK ) is approximately constant. Circuit arrangement according to claim 1 or 2, characterized in that the actuating force (F) via a travel (s) of the actuating device (ZM1, ZM2) is variable and corresponds to a predetermined force-displacement characteristic. Circuit arrangement according to Claim 3, characterized in that the first switching position (s ₀ ) of a switch-off position of the switching device ( 2 ) and the second switching position (s _end ) of a switch-on position of the switching device ( 2 ) and the force-displacement characteristic is such that the actuating force (F) - at the beginning of the travel (s) in the first switching position (s ₀ ) corresponds to an initial force (F _Anf ), - from a pressure point (s ₁ ) with the travel (s) to a maximum force (F _max ) at a maximum point (s ₂ ) increases, - behind the maximum point (s ₂ ) with the travel (s) drops and - in the second switching position (s _End ) one _End force (F _End ), which is smaller than the maximum force (F _max ) and greater than the initial force (F _Anf ). Circuit arrangement according to one of the preceding claims, characterized in that the drive circuit ( 3 ) has a time relay (ZR) and a power relay (K), wherein the timing relay (ZR) is designed to control the power relay (K) for a predetermined switch-on time (t) when actuated such that the power relay (K) controls the control voltage (U _Duration ) for the predetermined switch-on time (t) to the converter (W) switches. Circuit arrangement according to claim 5, characterized in that the predetermined switch-on time (t) is greater than the switching time for transferring the switchgear ( 2 ) from the first switching position (s ₀ ) to the second switching position (s _end ). Circuit arrangement according to Claim 5 or 6, characterized in that the drive circuit ( 3 ) is formed, after actuation of the timing relay (ZR) first via the converter (W) to build the DC link voltage (U _ZK ) and to control the actuator (ZM1, ZM2) in a pulsed manner after a time offset via the switching stage (SS). Circuit arrangement according to one of the preceding claims, characterized in that the converter (W) as a boost converter with a boost converter choke ( 32 ), a pulse width modulator ( 33 ) and a first semiconductor switch ( 35 ), wherein the boost converter throttle ( 32 ) on the one hand with the control voltage (U _duration ) and on the other hand via the first semiconductor switch ( 35 ) is connected to ground (GRD) and via a diode (D1) to the intermediate circuit (ZK) and the pulse width modulator ( 33 ), the first semiconductor switch ( 35 ) in a pulsed manner for generating the intermediate circuit voltage (U _ZK ) at the intermediate circuit (ZK) to switch. Circuit arrangement according to one of the preceding claims, characterized in that the intermediate circuit (ZK) has a link circuit capacitor (ZM1, ZM2) connected to the actuating device (ZM1). 36 ) having. Circuit arrangement according to one of the preceding claims, characterized in that the switching stage (SS) comprises a pulse sequence circuit ( 37 ) and a second semiconductor switch ( 39 ), wherein the pulse sequence circuit ( 37 ) is formed, a pulse train for switching the second semiconductor switch ( 39 ) for generating a current flow through the actuator (ZM1, ZM2). Circuit arrangement according to one of the preceding claims, characterized in that the electromagnetic actuating device is formed by a tension magnet (ZM1, ZM2). Circuit arrangement according to one of the preceding claims, characterized in that the drive circuit ( 3 ) has two transducers (W) and two switching stages (SS) for driving two actuating means (ZM1, ZM2). Circuit arrangement according to one of the preceding claims, characterized in that the drive circuit ( 3 ) has a fuse (F1, F2) for interrupting a current flow through the actuator (ZM1, ZM2) in case of thermal overload. Switching device with a circuit arrangement according to one of the preceding claims, characterized in that the actuating force (F) of a force-displacement characteristic of the switching device ( 2 ) is adjusted.

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