DE10120189A1 - Protecting switching device with electromagnetic triggering has excess current trigger with magnetic windings that interacts with switch lock to bring it from contact position to open position - Google Patents

Abstract

The device has at least two current connections, a switch set with at least one pole, movable and fixed contacts connected between the current connections, a switch lock with a manual actuation element and an excess current trigger that interacts with the switch lock to bring it from a contact position to an open position and that has a first magnetic winding in the circuit between the current connections and a further magnetic winding. The device has at least two current connections (3,4), a switch set (5) with at least one pole, movable (7) and fixed (6) contacts connected between the current connections, a switch lock (9) with a manual actuation element (21) and an excess current trigger (11) that interacts with the switch lock to bring it from a contact position to an open position and that has a first magnetic winding (25) in the circuit between the current connections and a further magnetic winding (42).

Description

DE 199 46 098 is a residual current protection switching device known with a line protection switch interacts. The residual current circuit breaker device has a differential measuring device in the form of a Toroidal transformers, with the help of two, one Circuit belonging to conductors the current is detected. If the amount of current in both conductors is not the same flows, e.g. B. because an earth fault on the consumer side the magnetic fields in the toroid do not rise more on. A resulting magnetic field is created, which in generates a current proportional signal in a measuring coil. This signal arrives in an evaluation circuit, at the Output the control section of a triac is connected. The triac is connected to the two via a protective resistor Conductors belonging to the monitored circuit.  

If a fault current is measured, the control triggers circuit the triac, which then over the protective resistor was only limited by the protective resistor Short-circuit current causes. The current is measured that a circuit breaker in the supply line responds. The current activates the short-circuit releases direction in the circuit breaker.

Miniature circuit breakers that interact with the mentioned circuit are suitable, for example in the DE 44 06 670 explained. The circuit breaker is with a single-pole contact set, to which a fixed moving and moving contact. The mobile Contact is controlled and moved via a key switch. The key switch has an operating lever to optionally to put the key switch in a position in of the contacts touching each other, or in a position to transfer in which the contacts are separated are.

Furthermore, the well-known circuit breaker with an electromagnetic release device. The electromagnetic release device consists of a stationary cylindrical coil in which an armature axially be is mobile. The coil has few turns and is like this dimensioned so that in the event of a short circuit they anchor in Direction to the key switch moves to the key switch trigger.

In addition, the known circuit breaker another thermal release that responds and that  Switch lock should trigger if the current lasts longer only slightly above the permissible nominal current of the monitored th circuit.

Based on this, it is an object of the invention To create protective switching device which is able to evaluate another control signal.

This object is achieved with the line protective device with the features of claim 1 ge solves.

As with the well-known miniature circuit breaker at least one-pole contact set consisting of a fixed standing and a movable contact provided. the Movable contact is common in the prior art ch switch lock assigned to the movable contact to lead and optionally in the closed or open Hold position.

The key switch can optionally, by means of a Be toggle between its switching positions back and forth be moved here, or it can with closed gear replacement can be triggered by an overcurrent release. When released, the key switch moves the movable one Contact in the open position.

The overcurrent release has at least one magnet coil, which is usually due to a short circuit in the monitored circuit responds and dimensio accordingly is nated. In addition to this magnetic winding is one additional magnetic winding applied, which is dimensioned in this way is that it gets by with a smaller current around which  Actuate anchor belonging to overcurrent device. The new protective switching device is thus able to to work with very high control current as well as un depending on this, with a smaller tripping current.

The further magnetic winding can be more useful Way together with a differential current measuring device turn. The residual current measuring device detects one Differential current in the two belonging to a circuit Conductors. With the help of the difference signal an electro African circuit controlled, the output side with the white tere magnetic winding is electrically connected. This one further winding is more sensitive, d. H. for smaller ones Current generates the necessary anchor force, it needs Control circuit in the output no semiconductor device in is able to withstand a very high current like him for example in the arrangement according to DE 199 46 098, occurs. It is sufficient if the switching element has an output has sufficient dielectric strength since the two magnets Windings of the line protection device like a Transfor mator act, the magnetic winding for short circuit current monitoring represents the primary winding.

Instead of the fault current measuring device, a Circuit to be connected to the further winding, the monitors a current in a protective conductor, or the like chen.

For the rest, further developments of the invention are against stood by subclaims. Such notes should also combinations of colors are deemed to be claimed, to which none pressing embodiment is directed.  

In the drawing is an embodiment of the Ge the subject of the invention. Show it:

Fig. 1, the protective switching device according to the invention, in a longitudinal section illustrating the essential functions and

Fig. 2 circuit suitable for driving residual current protection.

Fig. 1 shows a line protection switch 1 modified according to the invention, as it is used in network installations, in order to protect the lines against overcurrent both by short circuit and against slight overcurrent. The circuit breaker 1 is illustrated schematically, only those parts are shown that are necessary for understanding the invention.

The circuit breaker 1 has a housing 2 which is provided for snapping onto a top hat rail and in which a first connection terminal 3 and a second connection terminal 4 for electrical lines are provided in a stationary manner. In the electrical power connection between the at terminals 3 and 4 , a switch set 5 be standing from a stationary contact 6 and a movable contact 7th The movable contact 7 is connected via a lit ze 8 to the terminal 3 , while the fixed contact 6 is connected to the terminal 5 in a manner to be described.

To actuate the movable contact 4 , a switch lock 9 is present, the device 11 by a Auslöseeinrich in the state with open contacts 6 and 7 can be transferred.

To the switch lock 9 includes a contact carrier lever 12 which is formed with two arms and by means of an elongated hole 13 on a housing-fixed axis 14 is pivotally gela gert. As shown, the movable contact 7 is rigidly attached to one end of the contact carrier lever 12 . At the lever end projecting beyond the axis 14 , a spring 15 supported on the housing 2 engages, which tends to pivot the contact carrier lever 12 into a position in which the two contacts 6 and 7 are separated from one another.

In addition, this part of the contact carrier lever 12 engages a toggle lever arrangement 16 , which is composed of a knee lever part 17 and a toggle lever part 18 . The toggle lever part 17 is connected via a hinge 19 , which is axially parallel to the housing axis 14 , with the Kontaktträ gerhebel 12 as shown. In addition, the toggle lever part 17 contains an elongated hole 21 into which the toggle lever part 18 engages with a corresponding nose. The toggle lever part 18 is otherwise rigidly connected to an actuating toggle 21 which is pivotally mounted on an axis 22 which is also fixed to the housing. All axes are parallel to each other. On the actuating knob 21 , a release lever 23 is also attached. The special orientation of the release lever 23 results from the following functional description.

By pivoting the actuating knob 21 in the position shown in Fig. 1, the free end of the toggle arm 18 , which slides in the slot 21 comes into a position which lies above a connecting straight line which is defined by the axes 22 and 19 . Characterized the contact carrier lever 12 is pivoted counterclockwise to bring the movable contact 7 on the fixed contact 6 to the plant. The abutment forms the housing-fixed axle 14, the contact support lever 12 applies against the with the right edge of the long hole. 13 The alignment of the elongated hole 13 is transverse to the longitudinal extent of the contact carrier lever 12 .

If the operating lever 23 is rotated counterclockwise in a manner to be described later, the toggle arm 18 pivots accordingly, so that the contact point between the toggle part 18 and the elongated hole 21 reaches the other side of the connecting straight line between the axes 19 and 22 , ie based on Fig. 1 down. As a result, the support of the knee lever part 17 on the toggle lever 18 is omitted, and the biasing spring 15 can pivot the contact carrier lever 12 clockwise. At the same time, it also rotates the actuating lever 21 counterclockwise while the toggle lever 16 bends. In order to improve the contact separation time, ie in order to be able to distance the two contacts 6 and 7 from each other a little without the switching lock 9 being fully triggered, the contact carrier lever 12 can be taken a little in advance clockwise around the axis 19 by appropriate measures be turned around. This movement enables the slot 13 , which is oriented tangentially with respect to the axis 19 .

The triggering device 11 comprises a pot 24 made of a material which is a good heat conductor, for example aluminum. The pot 24 carries on its outside a few turns first magnet coil 25 made of a thick copper wire. The thick copper wire is welded at 26 to a contact tab 27 , which leads to the terminal 4 .

The other end of the magnetic coil is welded at 28 to a holding plate 29 , which is connected below the pot 24 and to the left of it with a wide copper strip 31 . The copper strip 31 forms in a central section from the fixed contact 6 and below the pot 24 a wall of a spark quenching chamber 32nd

In the pot 24 there is a cylindrical core as a yoke 33 , which is held immovably in the pot 24 . A plunger 34, which is connected at its end in the pot 24 to an anchor 35 , passes through a bore in the yoke 33 . The armature is prestressed in the direction away from the yoke 33 by means of a compression spring 36 . The plunger 34 cooperates with a control lever 37 which is pivotally mounted on a housing axis 38 ge. The other end of the control lever 37 which projects beyond the axis 38 interacts with the actuating lever 23 .

The pot 24 extends in the direction of the control lever 37 , and there is a shoulder 39 on which a bime tall snap disk 41 rests. Due to the circular Bi metal snap disc 41 carries the plunger 34 through which bears with a shoulder on the bimetal disc 41st In the idle state, the armature 35 is displaced to the right by the compression spring 36 , as a result of which the plunger 34 is drawn into the pot 24 until the corresponding shoulder, which rests on the snap disk 41 , prevents a further movement to the right. In the water position, the plunger 34 just touches with its free end a corresponding actuating surface of the control lever 37 . This is in such a position that a movement of the actuating knob 21 into the position shown in FIG. 1 is not hindered.

If a short-circuit current occurs in the line that is looped over the contact points 3 and 4 , then it generates the magnetic coil 25 a magnetic field that moves the armature 35 in the direction of the magnetic hole 33 . As a result, the plunger 34 is driven out of the pot 24 to the left. The se to the left movement pivots the Steuerhe bel 37 clockwise around the axis 38 fixed to the housing, where, on the one hand, a nose shown in FIG. 1 strikes against the contact carrier lever 12 and, as before, he believes, before triggering the switch 9 from the fixed standing contact 6 lifts off. Simultaneously, the upper half of the axis 38 located end of the control lever 37 against the operating lever 23 to move it in the direction of the switch-off position, as mentioned above.

The solenoid 25 also serves as a heating element when an overcurrent occurs in the monitored line, which is more than 20% above the nominal value. The resulting warming is transferred via the pot and the shoulder 39 to the snap disk 41 , which, starting from the position shown, changes over when heated and forms a stomach pointing to the left. As a result, if the plunger 34 is taken along and, as mentioned above, the control lever 37 is pivoted clockwise.

In addition to the magnet coil 25 , a further magnet coil 42 is provided, which is also applied to the single-layer cylindrical magnet coil 25 as a cylinder coil and is insulated from it at least at one end.

The magnet coil 42 consists of a wire, the cross section of which is very thin compared to the wire from which the magnet coil 25 is made. A large number of turns can be accommodated with a small space requirement, with the result that the magnet coil 42 is able to generate a magnetic field in the armature 35 which has a comparable strength as the magnetic field through the magnet coil 25 , however at a current that is several orders of magnitude smaller. The arrangement is very space-saving and can easily be accommodated in the normal housing.

With the help of the additional solenoid 42, there is the possibility of triggering the circuit breaker 1 by other events than those which are monitored by the bimetallic disk 41 or the solenoid 25 .

For example, the additional solenoid 42 can be used to be acted upon by a residual current monitoring circuit 48 , as shown in FIG. 2 ge.

The fault current monitoring circuit 48 is highly schematic in order to explain the principle of operation. To the fault current monitoring circuit 48 includes a differential current measuring device 49 in the form of a ring core. A total of two lines 51 and 52 pass through the toroidal core 49 . The line 52 is connected to the connection terminal 4 and connects the connection terminal 4 to a connection terminal 53 , which leads to a consumer. The second line 51 connects a connection terminal 54 to a connection terminal 55 . Of these two connecting terminals, for example, the connecting terminal 54 is located on the network side, while the connecting terminal 55 is located on the consumer side. Line 52 forms a phase conductor and line 51 forms a neutral conductor.

The two lines 51 and 52 form two primary windings for the toroidal core 49th They generate mutually compensating magnetic fields in the toroidal core 49 if the currents on the two lines 51 and 52 have the same magnitude but are directed in opposite directions.

To detect the possible differential current, ie a resulting magnetic field in the toroidal core 49 , a secondary winding 56 consisting of several turns is wound up. The secondary winding 56 is connected to a trigger circuit 57 .

The trigger circuit 57 controls on the output side a control path of a triac 58 , for which purpose it is closed on a control electrode 59 and on one of the main electrodes 61 . The main electrode 61 is connected to the line 51 .

The other control electrode 62 of the triac 58 is connected to a connection 63 of the solenoid 42 , the end 64 of which is connected to the line 52, for example between the solenoid 25 and the connection terminal 4 .

To test the arrangement there may still be a momentary switch 65 which electrically connected the line 51 via a protective resistor 66 to the line 52 , in such a way that, electrically seen, the one connection point lies in front and the other connection point lies behind the toroidal core 49 . By closing the button 65 , a differential current can be generated which is proportional to the size of the ballast resistance.

The circuit arrangement shown works as follows:
If the circuit breaker 1 is in the switched-on state, ie the movable contact 7 rests on the fixed contact 6 , there is a galvanic connection between the connecting terminal 3 and the connecting terminal 53 . A consumer connected to the two terminals 53 and 55 can in this way be supplied with electrical energy from a network that is switched on to the terminals 3 and 54 .

If the consumer works properly, it generates a heat loss in the magnet coil 25 , which is however so small that the current temperature of the bimetallic snap disk 41 is not reached. The circuit breaker 1 remains in the switched-on state.

In the event of a short circuit, a greatly increased short-circuit current flows through the magnetic coil 25 , which, as previously mentioned, triggers the circuit breaker 1 . The same can happen if the current through line 52 is too high above the nominal current and thus the magnetic coil 25 heats the bimetallic snap disk 41 to the transition temperature.

Assuming an earth fault occurs in the connected consumer, the amount of current flowing through line 51 to the consumer is different in amount than the current flowing back from the consumer via line 52 to the network. The current difference leads to a voltage in the secondary winding 56 , which is evaluated by the trigger circuit 57 . If the current difference is below a predetermined threshold value, the trigger circuit 57 remains in its rest position. However, exceeds the difference of the streams in lines 51 and 52, a front given threshold, in the form of a voltage threshold which is predetermined in the trigger circuit 57, then generates the trigger circuit 57 at its output a trigger signal for the triac 58, the durchzündet thereupon. A current can now flow from line 52 through further magnetic coil 42 to line 51 . This current is sufficiently large to move the armature 85 in the sense of triggering the switching lock 9 to the left against the magnetic yoke 34 .

A triac has the property to clear the current at zero crossing. Therefore, it would extinguish at the next zero crossing of the AC current flowing through the solenoid 42 . A single magnetic pulse would not be able to move the armature 35 . For this reason, the control circuit 57 must ensure that the triac 85 is fired again and again over a sufficient number of network periods, so that the current through the magnet coil 42 is maintained over a sufficient number of network periods.

Within a short time after the detection of the fault current and the first switching on of the solenoid 52 , the armature 35 has started to move and the plunger 34 , based on FIG. 1, has shifted to the left. As explained above, this causes the switch lock 9 to be triggered and the electrical contact between the movable contact 7 and the fixed contact 6 to be canceled. As a result, the current through the magnet coil 42 is inevitably switched off, but the switch-off takes place at a point in time at which the switch lock 9 is triggered mechanically in a practically ready manner and a reversal into the previous state no longer takes place. The circuit breaker 1 inevitably disconnects.

In the above explanation, the invention has been presented as if the fault current monitoring circuit 48 were spatially separated from the circuit breaker 1 . Actually, it can easily be accommodated in the housing 2 . In the case of spatial separation, it is necessary to provide terminals for the connections of the solenoid 42 in order to be able to interconnect them in the manner shown in FIG. 2 with the fault current monitoring circuit 48 .

A circuit breaker has a magnetic coil to monitor the short circuit current. On this spool there is also an additional magnetic coil that is connected to lower current works. The magnet coil is made from a Residual current monitoring circuit is controlled and acts in this way with the same trigger mechanism as the short circuit monitoring and / or the nominal current monitoring.

Claims (7)

1. protective switching device ( 1 ) with electromagnetic tripping ( 11 ),
with at least two power connections ( 3 , 4 ),
with an at least single-pole switch set ( 5 ) which has a movable and a fixed contact ( 6 , 7 ) and which is electrically connected between the two current connections ( 3 , 4 ),
with a key switch ( 9 ),
which is assigned to the movable contact ( 7 ), which serves to guide the movable contact ( 7 ) and optionally to hold it in a contact position with the fixed contact ( 6 ) or in an open position in which the movable contact ( 7 ) does not touch the fixed contact ( 6 ), and that is seen with an actuator ( 21 ) to manually switch the key switch ( 9 ) back and forth between the two positions, and
with an overcurrent release device ( 11 ) which is set up to cooperate with the switch lock ( 9 ) in order to bring the switch lock ( 9 ) from the contact position into the open position, and the at least one first magnetic winding ( 25 ) which is electrically in the Circuit between the two power connections ( 3 , 4 ), and has a further magnetic winding ( 42 ). 2. Protection switching device according to claim 1, characterized in that the first magnetic winding ( 25 ) serves to detect a short circuit. 3. Protective switching device according to claim 1, characterized in that the further magnetic winding ( 42 ) is attached above the first magnetic winding ( 25 ), such that both magnetic windings ( 25 , 42 ) are able to cooperate with a common armature ( 35 ) , which serves to act on the key switch ( 9 ). 4. Protective switching device according to claim 1, characterized in that a control device ( 48 ) is provided which has an output ( 58 ) to which the further winding ( 42 ) is connected, and in that the control device ( 48 ) has a signal measuring device ( 49 ) for detecting a fault condition in connection with a circuit in which the protective switching device ( 1 ) is located. 5. Protection switching device according to claim 1, characterized in that the signal measuring device ( 49 ) is formed by a current difference measuring device which compares the current flowing through the closed contact set ( 5 ) with a current in another conductor ( 51 ), and that further magnetic winding ( 42 ) is energized when the detected current difference exceeds a predetermined limit value. 6. Protection switching device according to claim 1, characterized characterized that the measurement signal input a current Sor has a current in a protective conductor wakes. 7. Protective switching device according to claim 1, characterized in that the overcurrent device ( 11 ) additionally has a temperature-sensitive element ( 41 ) that responds to the temperature of the at least one first magnet winding ( 25 ).