EP1562212B1 - Earth fault currents protection device - Google Patents

Description

The present invention relates to a fault current protection switching device having a first current path for guiding a useful current, a second current path for returning the useful current and a test device comprising an electrical resistance and by means of which the first current path with the second current path is electrically connected. Optionally, the fault current protection switching device also comprises a summation current transformer whose first primary winding is formed by the first current path and whose second primary winding is formed by the second current path.

Residual current circuit breakers (RCCBs) and combined residual current circuit breakers (RCCBs) shall be equipped with a test device which, when actuated by a test button, simulates a fault current when the mains voltage is applied. The residual current operated circuit breaker must switch off at this simulated fault current and disconnect the circuit. If this is not the case when the test button is pressed, the residual current circuit breaker is defective and replacement is required. Furthermore, the test button must be automatically reset to the initial position after release and the test circuit must be disconnected again.

As a rule, the test device has a test circuit winding applied to the summation current transformer of the residual current circuit breaker, a switching element for closing and opening the circuit, an auxiliary switch, a test resistor for current limiting and a test button for triggering a test procedure. Often, a separate return spring is used for the test button. The auxiliary switch is required to avoid overloading the test resistor if the test button is pressed too long. For this purpose, the auxiliary switch is mechanically with the moving contact coupled to the circuit breaker, so that after opening the contacts of the circuit breaker and the test circuit is forcibly interrupted by the auxiliary switch.

In many cases, the individual elements are connected to assembly-less-friendly selector wires and soldered connections to form a test circuit. The large number of individual parts and the complex assembly have a negative effect on the manufacturing costs of the devices.

During the intermediate and final tests of the residual current circuit breakers, faulty devices with a broken test circuit are repeatedly detected, for example due to cold solder joints or broken jumper wires. The actual function of the residual current circuit breaker is still guaranteed. If this error occurs at a later time for consumers, the device is falsely claimed to be faulty and will not trip if a fault current occurs. The fact that only the test circuit is defective can not be detected by the consumer. Such defects not only entail repair costs, but also affect the overall quality level of the circuit breaker.

From the publication EP 0 456 586 A1 is a test circuit for a residual current circuit breaker known. Two current paths can be connected via a test device which has a spring contact element. The connection is made by a button, whereby the spring force of the spring contact element is overcome.

In addition, from the document DE 30 32 826 A1 a spring-type circuit breaker with a test button for switching on a resistor in a test circuit known. A torsion spring, which is connected to a connection terminal, can be pressed by means of a key on one connection of the resistor, so that the test circuit is closed.

The further publication DE 2 220 558 A1 discloses a spring circuit breaker with a V-shaped contact part. The free end of the contact part can be actuated via a button. In addition, this free end at the point where it is in contact with the button, arc-shaped.

The object of the present invention is therefore to propose a fault current protection switching device, which is easier to assemble and less prone to error.

According to the invention, this object is achieved by a fault current protection switching device having a first current path which is connected to a terminal for connecting an external conductor, for carrying a useful current, a second current path for returning the useful current and a test device comprising an electrical resistance and with the aid of the first current path is electrically connectable to the second current path, wherein the test device comprises an electrical connection line, one end of which is designed as a spring contact element, so that the electrical connection between the first flow path and the second flow path can be established by overcoming the corresponding spring force. The spring contact element has a circular arc-shaped portion. This makes it easier to reset the test button in your guide. The connection line is connectable to the resistor directly at the first end and connected directly to the terminal at the opposite second end.

Advantageously, the number of individual parts and the solder joints can be reduced compared to conventional solutions. In addition, the use of non-rigid parts, such as selector wires, can be avoided. In this way, failures in production and operation due to interruptions in the test circuit due to defective solder joints, wire breaks and malfunction in pressing the test button in number reduce.

Consequently, such a realization according to the invention of the test circuit also results in a corresponding quality improvement.

Preferably, the test device of the residual current circuit breaker with the summation current transformer whose one primary winding is part of the test circuit. This makes the residual current circuit breaker even more robust.

Conveniently, the residual current circuit breaker according to the invention has a test button, which is held by the spring force of the spring contact in the OFF position, in which the two current paths are not connected to one another via the test device. In particular, this test button can be guided loosely in a housing section of the residual current circuit breaker. This results in a very simple implementation possibility for activating the test circuit and it can be dispensed in particular to a special spring for the test button.

The test device may further comprise an auxiliary switch with which the electrical connection while holding the test button, d. H. closed test circuit, between the first and second current path is interrupted. This auxiliary switch can be used so that the current-limiting resistor is not damaged if the test button is pressed too long.

In a special embodiment of the residual-current-protective switching device according to the invention, the auxiliary switch can be electrically coupled with a cutting connection to an element of the test device. As a result, an assembly-unfriendly and error-prone solder joint can again be avoided. Alternatively, the auxiliary switch may also have a conductor section, with which the auxiliary switch by a force-locking connection to an element of the test device electrically can be coupled. These non-positive connection is preferable to a solder joint for the reasons mentioned.

FIG 1

einen erfindungsgemäßen Prüfstromkreis, dessen Schalter geschlossen ist, in perspektivischer Darstellung;

FIG 2

den Prüfstromkreis von FIG 1, dessen Schalter offen ist;

FIG 3

eine Seitenansicht einer Prüftaste in der Schaltstellung EIN; und

FIG 4

eine Seitenansicht der Prüftaste in der Schaltstellung AUS.

The present invention will now be explained in more detail with reference to the accompanying drawings, in which:

FIG. 1

a test circuit according to the invention, the switch is closed, in perspective view;

FIG. 2

the test circuit of FIG. 1 whose switch is open;

FIG. 3

a side view of a test button in the ON position; and

FIG. 4

a side view of the test button in the switching position OFF.

The exemplary embodiment described in more detail below represents a preferred embodiment of the present invention. In the case of the described RCD, the test device has been implemented such that the individual elements are arranged such that no jumper wires and solder connections are required in the test circuit. Thus, the above errors can not occur.

This in FIG. 1 schematically illustrated residual current circuit breaker has a first terminal 4 for a phase conductor 3a and a second terminal 12 for a neutral 3b. The two conductors 3a and 3b are guided in a known manner by a summation current transformer 20, where they form the primary windings. The secondary winding of the summation current transformer 20 is guided to a trigger 6 of the residual current circuit breaker. If the opposing currents in the conductors 3a and 3b have different amounts, ie a fault current is present, a voltage is induced in the secondary coil of the summation current transformer 20 and the trigger 6 is activated.

To test the residual current device, a fault current is simulated with the aid of a test device, so that the Residual current circuit breaker, especially the trigger 6 triggers. The test device essentially consists of a circuit which connects the phase conductor 3a to the neutral 3b. For current limiting, the test circuit has a resistor 5. The test circuit is closed manually by a test button 2.

The test circuit is designed so that the primary winding of the neutral conductor 3b in the summation current transformer 20 is also used as Prüfstromkreiswicklung. For this purpose, the test circuit runs starting from the terminal 4 via a Prüfkontaktdraht 1, the resistor 5 and other switching elements to the neutral conductor 3b, which is performed as a primary winding through the summation current transformer 20 and ends in terminal 12. In this way, the current-carrying primary winding of the summation current transformer 20 is simultaneously used as Prüfstromkreiswicklung. Thus, an additional Prüfstromkreiswicklung, as used in conventional devices, in the inventive RCD circuit breaker is not required.

The Prüfkontaktdraht 1 thus forms the electrical connection line between the terminal 4 and the resistor 5. In addition, it has a resilient end 1a at the end facing away from the terminal 4 and thereby serves as a switching element for opening and closing the test circuit. At the same time, the test button 2 is held in the OFF position by the resilient end 1a of the test contact wire 1.

When operating the test button 2 loosely guided in the housing of the FI / LS device according to FIG. 3 In the switch position ON, the test circuit is closed by contacting the resilient end 1a of the test contact wire 1 with a connecting wire 5a of the resistor 5 and switching the resistor between the phase and the neutral conductor. In this case, a simulated fault current is generated, which brings the trigger 6 of the residual current switch to respond and this off via a force storage device.

When releasing the test button 2 according to FIG. 4 this is returned to the starting position by the spring properties of the Prüfkontaktdrahts 1 and the test circuit is interrupted. For this purpose, at the resilient end 1a of Prüfkontaktdrahts 1 a circular arc-shaped formation 1b is attached. With this circular-shaped shaping 1b it is achieved that the line of action of the restoring force F always runs parallel to the guide surfaces 7 of the test button 2 formed by the housing in each test button position. Undesirable lateral forces, which occur with straight spring legs, and a catching of the test button, which can be caused by tilting, are thereby avoided.

Following the resistor 5 is corresponding to the 1 and 2 in the test circuit, an auxiliary switch 8, which is designed as a leaf spring arranged. This auxiliary switch 8 is mounted in the housing of the RCCB so that it contacts a wire end 5b of the test resistor 5 and a second leg 8b a neutral contact 9 in the ON position of the switch with a first leg 8a and thus the Test circuit includes, as in FIG. 1 is shown. The required contact pressure is generated by the inherent resilience of the auxiliary switch 8.

Is the RCCB open, d. H. the moving contact 10 moved away from the fixed contact 11, so also connected to the moving contact 10 neutral contact 9 is moved away from the second leg 8b of the auxiliary switch 8. In this OFF position of the residual current circuit breaker, the auxiliary switch 8 thus interrupts the test circuit and prevents further actuation or too long pressing the test button 2, a burnout of the resistor 5 and thus damage to the residual current circuit breaker.

Like from the Figures 1 and 2 can still be seen, has the auxiliary switch 8 at the end of its first leg 8a a fork-shaped formation 8 c, which positions the test resistor 5 in its installed position. The electrical connection can be made at this connection point, for example by soldering. Alternatively, a cutting connection can be used for this, with which a positive connection is achieved when pressing the wire 5b of the resistor 5 in the fork-shaped formation 8c of the auxiliary switch 8. For this purpose, the fork-shaped groove 8c is formed at its end smaller than the diameter of the resistance wire 5b. Another possible connection between the resistance wire 5b and the first leg 8a of the auxiliary switch 8 would be in a non-positive connection. In this case, the first leg 8a at a correspondingly designed rotatable mounting of the contact portions 8a and 8b in the housing automatically when turning on the FI or RCCB, when the moving contact 10 is moved to the neutral contact 9, against the wire end 5a of the test resistor 5 pressed.

With the test circuit closed (cf. FIG. 1 ) Thus, the current flows at a feed into the terminal 4 via the Prüfkontaktdraht 1, the test resistor 5, the auxiliary switch 8, the neutral contact 9, the moving contact 10, the fixed contact 11 and formed as a primary winding of the summation current transformer 20 neutral 3b to the terminal 12th

Claims (6)

1. Residual-current-operated circuit breaker device having

   - a first current path (3a) which is connected to a terminal (4) for connecting an external conductor for the purpose of conducting an active current,

   - a second current path (3b) for the purpose of feeding back the active current and

   - a test apparatus which comprises an electrical resistor (5) and with the aid of which the first current path (3a) can be electrically connected to the second current path (3b), and which includes an electrical connecting line (1), the first end (1a) of which is embodied as a spring contact element, such that the electrical connection between the first current path (3a) and the second current path (3b) can be established by overcoming the corresponding spring force, wherein the connecting line (1) can be connected directly to the resistor (5) at the first end and is directly connected to the terminal (4) at the opposite second end,

   characterised in that

   - the spring contact element is embodied in such a way that the line of action of the spring force is always parallel to a predefined direction of movement of a test key (2) of the test apparatus.
2. Residual-current-operated circuit breaker device according to claim 1 which comprises a test key (2) which is held in the OFF position, in which the two current paths (3a, 3b) are not connected to each other via the test current apparatus, by means of the spring force of the spring contact.
3. Residual-current-operated circuit breaker device according to claim 2, wherein the test key (2) is guided loosely in a section of the housing of the residual-current-operated circuit breaker device.
4. Residual-current-operated circuit breaker device according to one of the preceding claims, wherein the test current apparatus comprises an auxiliary switch (8) by means of which the electrical connection between the first and second current path (3a, 3b) can be interrupted.
5. Residual-current-operated circuit breaker device according to claim 4, wherein the auxiliary switch (8) can be electrically coupled to an element of the test current apparatus by means of an insulation displacement connection.
6. Residual-current-operated circuit breaker device according to claim 4, wherein the auxiliary switch (8) has a conductor section (8a, 8b) which can be electrically coupled to an element of the test current apparatus by means of a force-fit connection.

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