CH661148A5 - SWITCHING DEVICE WITH SWITCHING ELEMENTS FOR OPENING AND CLOSING ELECTRICAL CIRCUITS. - Google Patents

Description

The invention relates to a switching device according to the preamble of claim 1.

Such a switching device has been e.g. known from U.S. Patent 4,251,845. In this known device, the control of the three switching elements takes place via a series of auxiliary relays, the switching sequence of which is predetermined by contacts switched on in their control circuits. In addition to a switch-on and switch-off command, this control is only influenced by an auxiliary contact of the magnetically controlled switching device located in the main circuit, which releases the further sequence of the switching sequence when switching on and off.

The disadvantage of this device is that the switch-on time of the electronic switch must be dimensioned relatively long due to the tolerances of the pull-in and drop-out times of the auxiliary relays, which means that the electronic switch must absorb a correspondingly high power loss and must be selected accordingly. In addition, in the known case, the switching sequence when the main circuit is interrupted depends on dropout delays formed by capacitors connected in parallel to the coils of auxiliary relays, which can result in incorrect switching due to changes in the capacitance of the capacitors in the course of the operating time, which can lead to destruction, particularly of the electronic switch .

The object of the invention is to propose a switching device of the type mentioned in the introduction, in which incorrect control of the switching elements is reliably avoided.

The object is achieved according to the invention by the features specified in the characterizing part of claim 1.

This makes it possible to only continue in the switching sequence as soon as the previous switching command has been executed. However, this also makes it possible to dispense with safety clearances between the individual switching steps, as are required in the known case, whereby a reduction in the on-time of the electronic switch is achieved despite increased safety.

By means of a preferred embodiment according to claim 4 it can be achieved that, in contrast to the known solution according to US Pat. No. 4,251,845, the electronic switch is disconnected from the main circuit on the network side. This largely protects the electronic switch against the effects of traveling waves or short-circuits on the load side, which can lead to the contacts being torn open due to the current forces in the area of the constrictions in the current paths caused by the contact points, which may result in the arcing that is formed being extinguished and thus high induction voltages can occur.

In an embodiment according to claim 5, it can be ensured that the switching sequence is only continued when the contacts in the main circuit are actually closed.

Embodiments of the invention will now be explained in more detail with reference to the drawings. Show:

1 shows an embodiment of a switching device for connecting or disconnecting a load to a network with always the same phase sequence,

2 shows a different embodiment compared to FIG. 1,

3 shows a switching device for connecting or disconnecting a load with an optional phase sequence,

Fig. 4 is a block diagram of a control unit for a switching device according to FIGS. 1 or 2 and

5 shows a block diagram of a control unit for a switching device according to FIG. 3.

The magnetically controlled switching device 1, 1 'has contacts 4 in the main circuit which control the connection of the mains connections LI, L2, L3 to the load 5. A series circuit consisting of a contact 6, 6 'of an auxiliary switching device 2, 2' and an electronic switch 3 acting as a disconnector is connected in parallel with each of the contacts 4, 4 '.

2 and 3, auxiliary contacts 7, 7 'and 8, 8' are provided to control the switching function of the switching devices 1, 1 'and the auxiliary switching device 2, 2', which, like the switching devices 1, 1 'and Auxiliary switching devices 2, 2 'and the electronic switch 3 are connected to a central control unit 9.

This control unit 9 is supplied by the network via a phase LI and the neutral conductor and is connected to the usual on and off buttons 10, 10 'and 11, respectively. Likewise, a fault message 12 is connected to the central controller 9.

In the embodiment according to FIG

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Chung the switching function of the switching device 1 or the auxiliary switching device 2 and the electronic switch 3 current transformers 13, 14 provided, of course, current transformers can be arranged in each phase to achieve exact monitoring.

If a switch-on command is transmitted to the central control unit 9 in the switching device according to FIG. 1 or 2 by pressing the on button 10, the control circuit for the auxiliary switching device 2 is activated after passing through a test loop and the latter is brought to close its contacts 6. After the feedback about the closing of the contacts 6 has been received by means of the auxiliary contact 8, the control circuit of the electronic switch 3 is activated and this switches through. The load 5 is thus connected to the network LI, L2, L3 via a parallel current path. The activation circuit of the magnetically controlled switching device 1 is then activated, so that it closes its contacts 4.

After the arrival of the feedback about the closing of the contacts 4 of the switching device 1 by means of the auxiliary contact 7 or the current transformer 13, the electronic switch 3 is blocked and then the control circuit of the auxiliary switching device 2 is reset to open the contacts 6 of the auxiliary switching device 2 again. Of course, instead of just one phase, all three phases can be monitored by current transformers 14.

If the off button 11 is pressed, which is upstream of the on button 10, as a result of which a switch-off command triggered by pressing the off button has priority over a switch-on command, the control circuit of the auxiliary device 2 is activated and the contacts 6 are closed. After the feedback via the Closing the contacts 6, but at the latest after a certain time, the control circuit of the electronic switch 3 is activated so that it changes to its conductive state.

As soon as the feedback about the successful connection of the electronic switch 3 has been received, but at the latest after a certain time, the control circuit of the switching device 1 is reset in order to open the contacts 4. If this has taken place, the control circuit of the electronic switch 3 is reset and the electronic switch 3 changes to its locked state, the control circuit of the electronic switch 3 being reset at the latest after a certain time has elapsed.

After resetting the control circuit of the electronic switch 3, the control circuit of the auxiliary switching device 2 is then reset so that its contacts 6 open and the switch-off cycle is ended.

In the embodiment according to FIG. 3, the switch-on and switch-off cycle takes place in the same way. Depending on whether the pushbutton 10 or 10 'is pressed, the auxiliary switching device 2 or 2' is subsequently controlled by the switching device 1 or 1 'in the sense of closing the contacts 6 or 6' or 4 or 4 '.

Before the corresponding activation of the auxiliary switching device 2 or 2 'is checked in the test circuit, however, whether none of the coils of the switching devices 1,1' and the auxiliary switching devices 2, 2 'is energized and none of the contacts 4, 4' and 6, 6 'closed is. In addition, the control circuits of the auxiliary switching devices 2, 2 'and the switching devices 1, 1' are mutually interlocked, so that as soon as a switch-on signal is sent to the control circuit e.g. of the auxiliary switching device 2 receives a blocking signal to the control circuits of the auxiliary switching device 2 'and the switching device 1', whereby these can only be activated after a switch-off command and a subsequent switch-on command triggered by pressing the button 10 '.

The arrangement of the electronic switch 3 on the load side of the auxiliary switching devices 2, 2 'connected in parallel makes it possible to use a single electronic switch 3 for both

Parallel circuits to the contacts 4, 4 'of the switching devices 1,1' to find the end.

A block diagram of a central control unit 9 for a switching device according to FIG. 1 or 2 is shown in FIG. 4, the illustration of the voltage supply being dispensed with.

The commands entered into the central control unit via the on or off button 10, 11 are stored in the memory 15, the output of which is connected to each of the control circuits 16, 17, 18, each of which is one of the switching elements of the switching device, namely the auxiliary switching device 2, the electronic switch 3 and the switching device 1 are assigned. Furthermore, the output of the memory 15 is still connected to a test circuit 19.

The test circuit 19 is also equipped with a current flow through the coil of the magnetically controlled switching device

1 responsive sensor 20, a sensor monitoring the position of the contacts 4 of the switching device 1, e.g. an auxiliary contact 7 or a current transformer 13 connected sensor 7, 13, a sensor 21 monitoring the switching state of the electronic switch 3, which e.g. responds to the supply of the ignition electrode of the electronic switch 3 and / or also to a current flow through the parallel circuit. Furthermore, the test circuit 19 receives signals from a sensor 22 which responds to the current flow through the coil of the auxiliary switching device 2 and from a sensor 23 which monitors the switching state of the contacts 6.

If a switch-on command now comes to the test circuit 19, it issues a switch command to the control 16 of the auxiliary switching device 2 if no current flows through the coils of the switching device 1 or the auxiliary switching device 2 and their contacts 4 or 6 are in the open position and the electronic switch 3 is also in its locked state.

If this is not the case, the switch-on command to the control circuit 16 of the auxiliary switching device 2 is omitted and a signal for activating the fault reporting circuit 24 is emitted.

The switch-on command to the control circuit 16 is simultaneously applied to a resettable timer 25, which is connected to a reset input of the control circuit 16 and, after the end of its expiration time, emits a signal to the reset input of the control circuit 16 in order to reset it. At the same time, this signal also activates the fault reporting circuit 24, which e.g. the lamp 12 controls.

However, the sequence of the timer 25, which is also connected to the sensor 23 monitoring the contacts 6 of the auxiliary switching device 2, does not occur if the closing of the contacts 6 is signaled within the expiry time of the timer 25.

As soon as the contacts 6 of the auxiliary switching device close

2 of the control circuit 16 connected to the sensor 23 is signaled, it issues a switch-on command to the control circuit 17 controlling the electronic switch 3, which is delayed by a timer 26 in order to avoid switching through the electronic switch 3 during a possible bouncing of the contacts 6 . If a switch-on command arrives from the control circuit 16 in the control circuit 17, which is connected to the sensors 7, 13 and 21 and 23, the latter checks whether the contacts 4 are still open and the contacts 6 are closed. If this is the case, the control electrode of the electronic switch 3 is acted upon by ignition pulses or a continuous signal and is thus kept in the switched-on state. If the above conditions are not met, the control electrodes of the electronic switch 3 are not acted upon and the fault reporting circuit 24 is activated. At the same time, a command to open the contacts 6 is given to the control circuit 16 of the auxiliary switching device 2.

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The activation of the fault reporting circuit 24 and the issuing of the command to open the contacts 6 to the control circuit 16 also occur if no ignition signals arrive at the control electrode of the electronic switch 3 within a certain time after the switch-on signal has arrived at the control circuit 17 or in the parallel circuit no current flows, which is monitored by the sensor 21 connected to the control circuit 17. In this case, the control circuit 17 is also reset.

If, on the other hand, a signal from sensor 21 corresponds to the proper switching of electronic switch 3, control circuit 17 emits a switching signal to control circuit 18, which is assigned to switching device 1, switching device 1 due to the switch-on signal coming from memory 15 closing of the contacts 4 is applied. At the same time this signal reaches a resettable timer 27, the output of which is connected to a reset input of the control circuit 18 and the fault reporting circuit 24. If a signal corresponding to the closed contacts 4 of the switching device 1 reaches the timer 27 within the running time of the timer 27, the timer is reset and there is no delivery of a reset signal to the control circuit 18 and a signal for activating the fault reporting circuit 24.

In the opposite case, the control circuit 18 is reset and the fault reporting circuit 24 is activated, and the control circuit 17 is reset via the timer 28, which is connected to the output of the timer 27 and a reset input of the control circuit 17, as a result of which the electronic switch 3 is in the blocking state transforms.

However, if a signal corresponding to the closed contacts 4 reaches the timer 27 and the control circuit 18 in good time, the latter issues a command to disable the electronic switch 3 to the control circuit 17.

As soon as the feedback from the sensor 21 about the blocking of the electronic switch 3 in the control circuit 17 arrives, the latter sends a signal for opening the contacts 6 of the auxiliary switching device 2 to the control circuit 16 via the timing element 26. If no such feedback is received within a certain time, the fault reporting circuit is activated

24 is activated and the signal for opening the contacts 6 is output to the control circuit 16.

This transmits the command to open the contacts 6 to the auxiliary switching device 2 and checks whether a signal corresponding to the opened contacts 6 arrives from the sensor 23 within a certain time. If this does not happen, the control circuit 16 emits a signal which activates the fault reporting circuit 24, but the command to open the contacts 6 is retained and is not reset.

If a switch-off command arrives at the central control unit by pressing the off button 11, this command is stored in the memory 15 and it outputs a corresponding signal at its output, which in turn reaches the test circuit 19 and the control circuits 16, 17 and 18.

The test circuit 19 only checks whether the contacts 4 of the switching device 1 are closed and the electronic switch 3 is blocked. If this is not the case or if this case does not occur within a certain time, the fault reporting circuit 24 is activated. In any case, however, a command to close the contacts 6 of the auxiliary switching device 2 is issued to the control circuit 16, the switch-off signal coming from the memory 15 being the one with the timing element

25 connected reset input is disabled. In addition, in the event of a switch-off signal coming from the memory, a switch-on command is given to the control circuit 17 after a certain time, regardless of whether the sensor 23 delivers a signal corresponding to the closed contacts 6 or not within a predetermined time. If such a signal does not arrive, then the fault reporting circuit 24 is activated after the timer 25 has expired.

The switch-off signal coming from the memory 15 also has the effect that the control circuit 17 brings the electronic switch 3 into the switched-on state even when there is no signal corresponding to the closed contacts 6 when the switch-on command arrives from the control circuit 16 and outputs a switch signal to the control circuit 18, which controls the switching device 1 in the sense of opening the contacts 4 on the basis of the switch-off signal from the memory.

If a signal corresponding to the open contacts 4 is now supplied by the sensor 7, 13, the control circuit 18 emits a signal for blocking the electronic switch 3 to its control circuit 17. However, if this signal does not occur, the timer 27 expires and the fault reporting circuit 24 is activated and after the timer 28 has elapsed, a blocking signal is sent to the control circuit 17.

The electronic switch 3 is thereby blocked and, after the insertion of a signal corresponding to the proper blocking of the electronic switch 3 by the sensor 21 or after a predetermined time has elapsed, a signal for opening the contacts 6 of the auxiliary switching device 2 is sent from the control circuit 17 to the control circuit 16 , in which case the fault reporting circuit 24 is also activated.

The control circuit 16 acts on the auxiliary switching device

2 in the sense of opening the contacts 6 and checks whether a signal from the sensor 23 corresponding to the open contacts 6 is present within a certain time. If this is not the case, the fault reporting circuit 24, which e.g. can be formed by an OR gate, activated, the control of the auxiliary switching device 2 in the sense of opening the contacts 6 is retained.

This ensures that the switch-off command is always executed, even if there are errors in the switching gears.

In the block diagram according to FIG. 5, a memory 15 is provided with two outputs which are interlocked with respect to a switch-on command and which are each assigned to one of the two pushbuttons 10, 10 ', but both assume the same switching state when a switch-off command is received.

Thus, only one of the two outputs of the memory 15 can emit a switch-on signal, this signal being retained until the button 11 is pressed, regardless of whether one or both buttons 10, 10 'are pressed.

In addition to the sensors 20, 7, 22 and 23 monitoring the switching device 1 and the auxiliary switching device 2 or their contacts 4 and 6, the test circuit 19 is also connected to the sensors 20 ', 7' monitoring the switching device 1 'and the auxiliary switching device 2', 22 'and 23' as well as with the electronic switch

3 monitoring sensor 21 connected. In addition, the test circuit is still connected to both outputs of the memory 15 via an OR gate 30. If a switch-on command reaches the test circuit 19 via this OR gate, it checks whether current flows through none of the coils of the switching devices 1 and 1 'and the auxiliary switching devices 2 and 2' and no contacts 4 or 4 'and 6 or 6' are closed are and whether the electronic switch 3 is in its locked state. If these conditions are met, the test circuit 19 issues a switching command which is supplied to one of the two control circuits 16, 16 'via one of the two AND gates 31, 32, which establish a link to one of the two outputs of the memory 15 , which are assigned to the auxiliary switching device 2 or 2 '. The two control circuits are mutually locked because the outputs of the AND gates 31 and 32

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in addition to the set input of one control circuit 16 or 16 'and also via one OR gate 33, 34 each to the reset input of the other control circuit 16 or 16'. The second inputs are connected to the output of the timing element 25, which is connected to the sensors 23 and 23 'monitoring the positions of the contacts 6 and 6' of the auxiliary switching devices 2, 2 'and which signals one of the two sensors by the closed position of these contacts an expiry time is resettable.

In principle, the switch-on and switch-off process takes place in the embodiment according to FIG. 5 in the same way as shown in FIG. 4, and the fault reporting circuit 24 is also activated under the same conditions.

The control circuit 17 of the electronic switch 3, like the test circuit 19, is connected to both outputs of the memory 15 via the OR gate 30. Furthermore, the control circuit 17 is connected to the position of the contacts 4 and 4 'monitoring sensors 7 and 7' and to the contacts 6 and 6 'monitoring sensors 23 and 23'. If a switch-on command arrives via the timer 26 from the control circuit 16 or 16 ', the control circuit 17 checks whether the contacts 4 and 4' are still open and the contacts 6 or 6 'are not closed, but both contact groups 6 and 6' are closed and then controls the control electrode of the electronic switch 3 so that it switches on.

If a signal corresponding to the through-connected electronic switch 3 is received by the sensor 21 in the control circuit 17, the latter outputs a switching signal which is one of the two control circuits via one of the AND gates 35, 36, the second inputs of which are connected to the outputs of the memory 15 18, 18 'which are assigned to the switching devices 1 and 1', respectively. At the same time, the timer 27 which can be reset by a signal corresponding to the closed contacts 4 or 4 'is also started.

The outputs of the AND gates 35, 36 are connected not only to the set inputs of the control circuits 18, 18 'but also to OR gates 38 and 37, the outputs of which are connected to the reset inputs of the control circuits 18 and 18' and

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whose second inputs are connected to the output of the timer 27.

This again results in mutual locking of the control circuits 18 and 18 '.

As soon as a signal corresponding to the closed contacts 4 or 4 'arrives at the control circuit 18 or 18' from the corresponding sensor 7 or 7 ', it issues a command to disable the electronic switch 3 to the control circuit 17.

The further course of the switch-on cycle takes place as in the exemplary embodiment according to FIG. 4, although signals which cause contacts 6 and 6 'to open are supplied to both control circuits 16 and 16'.

If both outputs of the memory 15 deliver the same signals, this represents a switch-off signal and the test circuit 19 checks whether the contacts 4 or 4 'of a switching device are closed and the electronic switch is blocked. In any case, a switching command from the test circuit 19 to the two AND gates 39, 40 whose negated input is connected to the output of the OR gate 30 and can therefore only be switched through in the event of a switch-off command. The third input of these gates 39, 40 is connected to the sensors 7 and 7 ', so that only that one of the two gates 39, 40 can switch through which is connected to the sensor 7 or the sensor which supplies a signal corresponding to the closed contacts 4 or 4' 7 'is connected.

The further course of the switch-off cycle is identical to the cycle described in the course of the explanation of FIG. 4 until the switching signal of the control circuit 17 is delivered to one of the control circuits 18 or 18 '.

The switching signals are passed on when the switch-off command is present at the two outputs of the memory 15 via the AND gate 41 whose inverting input is connected to the output of the OR gate 30 and can therefore only switch through in the event of a switch-off command. The output of this AND gate 41 is via decoupling elements 42, 43 e.g. Diodes connected to the set inputs of the control circuits 18, 18 ', so that both control the associated switching devices 1, 1' due to the pending switch-off command in the sense of opening the contacts 4, 4 '.

The further steps of the switch-off cycle are the same as those described in connection with FIG. 4.

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Claims (6)

661148 1. Switching device with switching elements for opening and closing electrical circuits, in which a magnet-controlled contact in parallel to each contact in the main circuit to be switched. Switching device, an electronic switch and a contact serving as a disconnector of a further magnetically controlled auxiliary switching device are connected in series and a control unit is provided, which switches the electronic switch through before each switching state change of the magnetically controlled switching device located in the main circuit and then blocks it again, the control unit switching the series to the electronic one Switch-lying contacts of the auxiliary switching device closes before the electronic switch is switched through and opens after the electronic switch is blocked, characterized in that the control unit (9) for the switching device (1, 1 ') closes the electronic switch (3) and the auxiliary switching device (2 , 2 ') each have a control circuit (16, 16', 17, 18, 18 ') which monitors the sensors with the switching and / or control state of the respective switching element (1, 1', 2, 2 ', 3) (7, 7 ', 8, 8', 13, 14, 20, 20 ', 21, 21', 22, 22 ', 23, 23') connected test loops and m that monitors the implementation of the switching step assigned to the associated control circuit and that the control circuits are connected to one another and that each control circuit (16, 16 ', 17, 18, 18') emits an enable signal to the downstream control circuit after the switching step assigned to it has been carried out. 2. Switching device according to claim 1, characterized in that the control circuits are connected to one another via timing elements (25, 26, 27, 28). 2nd PATENT CLAIMS 3. Switching device according to claim 1 or 2, characterized in that the control unit (9) comprises a test circuit (19) monitoring the switching and / or control states of the switching elements in the stable starting positions of the switching device. 4. Switching device according to claim 1, characterized in that the control circuit of the electronic switch (3) with that of the magnetically controlled auxiliary switching device (2, 2 ') is linked, the falling edge of the control current of the electronic switch via a delay element a command to open the Contacts of the auxiliary switching device (2) are triggered. 5. Switching device according to one of claims 1 to 4, characterized in that an auxiliary contact (7, 7 ') is provided for monitoring the position of the contacts in the main circuit of the magnetically controlled switching device (1, 1'). 6. Switching device according to one of claims 1 to 5, characterized in that the monitoring of the switching state of the electronic switch (3) is carried out by a sensor responsive to its control current.