EP2932521B1 - Automatic circuit breaker with auxiliary short circuit - Google Patents

Description

The present invention relates to a circuit breaker for securing a phase with an input terminal, an output terminal, a current path electrically connecting the input terminal and the output terminal, a disconnecting device disposed in the current path and configured to interrupt it upon actuation, and a monitoring device which is designed to monitor the current in the current path and to actuate the disconnecting device upon detection of an overcurrent. Furthermore, the invention relates to a fuse arrangement with a plurality of above-mentioned circuit breaker for use in a multi-phase supply line, each phase is secured with a circuit breaker.

In circuits electrical lines are protected from heating and short circuit by the use of safety devices that cause, for example, in the event of a short circuit interruption of the line. Such safety devices can be designed as automatic circuit breakers or as fuses.

Such a circuit breaker is connected to its input terminal to a power source. Its output terminal is connected to the load, with the input terminal and the output terminal connected via a current path. In the current path, a separation device is arranged, which is designed to interrupt this upon actuation. The separator is usually designed as a switch, more precisely as an opener. Of the The automatic circuit breaker additionally has a monitoring device which monitors the current in the current path. When detecting an overcurrent, the separation device is actuated by the monitoring device, so that it interrupts the current path. Usually, the circuit breaker on an actuating element which is actuated upon actuation of the separating device, so that the actuation of the separating device is recognizable from the outside. In addition, the separating device can be actuated manually via the actuating element in order to cancel or bring about the interruption.

When the current path is interrupted, an arc occurs, so that the current in the current path is not interrupted immediately. The current is only completely interrupted when the arc is extinguished. Therefore, known circuit breakers are usually performed with extinguishing chambers, in which the arc enters and is deleted. In the quenching chamber, the arc is divided by quenching plates and interrupted.

From the occurrence of the arc, the resistance rises above the separator and the current decreases. The switch-off time to extinction of the arc is in known circuit breakers at least 4 ms. During this time, however, damage or even destruction of the load connected to the output terminal of the circuit breaker can occur.

In multi-phase supply systems, each phase is protected with such a circuit breaker.

In the application often occurs the problem that the permissible parameters of a downstream switching device, For example, a contactor or a motor switching device can be exceeded, so that circuit breakers must be selected, which already trigger at low currents. Alternatively or additionally, the switching devices are oversized, which is associated with increased costs and can lead to additional losses. This leads to a design conflict in applications with high peak currents, such as may occur when starting up motors. Also, each individual dimensioning of the system is required.

In addition, while well-known from the prior art current-limiting switching elements quickly turn off high short-circuit currents, but act at elevated continuous currents too slow, so that can flow too large currents through the downstream loads and switching devices. This makes coordination between the circuit breaker, the power supply and the load even more difficult.

In this context, according to the IEC 60947-4-1 standard, within the scope of short-circuit protection, a distinction is made between two types of assignment that describe the permissible degree of damage of a device or a load in the case of overcurrents. With assignment type 1, downstream devices, such as contactors or semiconductor switching devices, may be destroyed. In assignment type 2, the downstream devices must in principle remain functional. While mechanical switching devices, such as contactors, are often assigned to assignment type 2, semiconductor switching devices, for example for motors, usually meet the requirements of assignment type 1.

In this context is from the WO 2010/099903 A1 a multi-pole electrical self-switch, in particular a multi-pole circuit breaker, known. The self-switch comprises two juxtaposed self-switches, each of which is a series circuit of a main current path, a normally closed first switch and an electromagnetic tripping device connected between a first and a second electrical connection, an electrothermal tripping device parallel to the one normally closed second switch having the main current path, so that the electrothermal tripping device is normally bridged by the main current path, and a switching mechanism for opening the first switch and for actuating a driver, which transmits the switching movements of the switching mechanism of the one self-switch to the switching mechanism of the other self-switch. The electromagnetic trip device has a first armature for opening the second switch upon reaching a first threshold current and a second armature for opening the first switch and for actuating the switching mechanism on reaching a second threshold current, which is greater than the first threshold current.

Based on the above-mentioned prior art, the invention is therefore an object of the invention to provide a circuit breaker and a fuse assembly of the type mentioned above, which allow improved protection of downstream loads and switching devices against overcurrents.

The object is achieved by the features of the independent claims. Advantageous embodiments of the invention are specified in the subclaims.

Thus, according to the invention, a circuit breaker for protecting a phase is provided with an input terminal, an output terminal, a current path electrically connecting the input terminal and the output terminal, a separator disposed in the current path and configured to interrupt it upon actuation Deriving terminal, a discharge path, which is connected at its one end to the current path between the separator and the output terminal and at its other end to the discharge terminal, a connection device which is arranged in the discharge path and designed to connect through this in an operation, and a Monitoring device which is designed to monitor the current in the current path and to operate the disconnecting device and the connecting device upon detection of an overcurrent, so that the currents during switching of the disconnecting device after switching the connecting device over d The drainage terminal drain, the monitoring device is designed to perform a continuous current monitoring and a short-circuit current monitoring.

According to the invention, a fuse arrangement with a plurality of above-mentioned automatic circuit breakers for the Used in a multi-phase supply line, each phase is secured with a circuit breaker, and the circuit breakers are coupled together.

The basic idea of the present invention is thus to provide a circuit breaker which ensures reliable protection of downstream loads from overcurrents by the connection of continuous current and short-circuit current, and whose protective effect occurs particularly rapidly by currents during the switching of the separator by occurring arcs on the discharge terminal be derived. The circuit breaker thus has two characteristics, on the one hand the line protection to protect against excessive continuous currents that are above a permissible maximum continuous current, and on the other hand a short-circuit protection to ensure protection against excessive peak currents. The currents during the switching of the separating device can flow off after switching the connecting device via the discharge terminal, so that the protective function of the circuit breaker already occurs very quickly. Depending on the switching times of the connection device, times of the order of magnitude of 0.2 ms can be achieved, after which the load is substantially without current.

Preferably, the monitoring device is designed for the common actuation of the separating device and the connecting device. Particularly preferred is a simultaneous actuation of the separating device and the connecting device by the monitoring device.

The automatic circuit breaker is connected with its input terminal to a power supply and at its output terminal to a load, which may have an electrical switching device connectable. The discharge terminal is preferably connectable to a ground or a neutral, over which a current can flow during switching. The separating device is preferably designed as an opener for interrupting the current path. The connecting device is usually designed as a closer for connecting through the Ableitpfades.

In multi-phase power supplies, each circuit breaker is connected with its input terminal to a phase of the power supply. The Ableitklemmen are preferably connected to a ground or a PE conductor over which the current can flow when switching. Alternatively, the discharge terminal can be connected to a different phase or a synthetic star point.

In an advantageous embodiment of the invention, the circuit breaker is developed such that the monitoring device has a bi-metal switch for continuous current monitoring. Thus, the heat is detected in the current path to detect an excessive line current. By choosing the bi-metal characteristic, the protective behavior can be selected.

In an advantageous embodiment of the invention, the circuit breaker is developed such that the monitoring device has a magnetic switch for short-circuit current monitoring. Accordingly, a magnetic quick release as short-circuit protection for fast processes, ie fast peak currents, respectively. The sensitivity of the short-circuit protection can be achieved by the property of the magnetic material. The time course of the magnetic field corresponds to a hysteresis curve. Preferably, a magnetic field is generated by the overcurrent, so that with the aid of a relay coil and armature actuation can take place.

In an advantageous embodiment of the invention, the circuit breaker is developed such that the circuit breaker has a coupling device with which the separating device and the connecting device are coupled for common operation, and the monitoring device is designed for actuating the separating device and the connecting device via the coupling device. The monitoring device therefore only has to actuate the coupling device, whereby the separating device and the connecting device are automatically actuated. The coupling device can in principle be designed as desired. For example, the coupling device may be an electrical or electronic coupling device. Particularly preferably, the coupling device is a mechanical coupling device. More preferably, the actuation of the coupling device is effected by a relay.

In an advantageous embodiment of the invention, the circuit breaker is developed such that the circuit breaker has an actuating element which is actuated by the monitoring device during an actuation, so that the actuation is recognizable from the outside. Preferably, the actuating element is connected to the coupling device.

In an advantageous embodiment of the invention, the circuit breaker is developed such that the Actuator is executed to perform a manual operation of the separating device and the connecting device. Accordingly, the circuit breaker can be manually operated to disconnect a downstream load from the power supply. Preferably, the actuating element is connected to the coupling device.

In an advantageous embodiment of the invention, the fuse arrangement is developed such that the circuit breakers are mechanically coupled together. Due to the mechanical coupling, the circuit breakers can mutually transmit an operation by their respective monitoring device on the other circuit breakers. The mechanical coupling is particularly reliable and easy to manufacture.

In an advantageous embodiment of the invention, the fuse arrangement is further developed such that the circuit breakers have an actuating element for a manual actuation of the separating device and the connecting device, and the circuit breakers are mechanically coupled to each other via a coupling element. The mechanical coupling is particularly reliable and allows easy transfer of actuation between the circuit breakers. Particularly preferably, the coupling element is designed as a separate component for attachment to the actuating elements. Thus, the coupling of the circuit breakers can be performed flexibly. In particular, available circuit breakers can readily be coupled together, so that at any time a fuse arrangement can be formed.

In an advantageous embodiment of the invention, the securing arrangement is developed such that the coupling element has a manual actuator for manual operation of the coupled circuit breaker. Thus, the fuse assembly can be manually operated in accordance with the operation of the circuit breaker to separate the load from the power supply for all phases simultaneously. Preferably, the manual actuator for manual operation is carried out both for the common separation of the current paths of the individual circuit breakers as well as for interconnecting the current paths, according to the function of the actuating element of the circuit breaker. Particularly preferably, the manual actuator is designed such that the operation is visible from the outside.

In an advantageous embodiment of the invention, the fuse arrangement is designed as an integral device.

The invention will be explained in more detail with reference to the accompanying drawings with reference to preferred embodiments.

Fig. 1

ein Schaltbild mit einer Sicherungsanordnung, die zwischen einer mehrphasigen Stromversorgung und einer mehrphasigen Last angeordnet ist,

Fig. 2

eine Detailansicht des Schaltbilds aus Fig. 1, in der nur ein Sicherungsautomat der Sicherungsanordnung dargestellt ist,

Fig. 3

eine Detailansicht des Schaltbilds aus Fig. 2, in welcher der in Fig. 2 gezeigte Sicherungsautomat im Detail dargestellt ist,

Fig. 4

ein Diagramm eines Laststromverlaufs bei Verwendung eines konventionellen Sicherungsautomaten bei der Erfassung eines Überstroms,

Fig. 5

ein Diagramm eines Laststromverlaufs bei Verwendung eines erfindungsgemäßen Sicherungsautomaten bei der Erfassung eines Überstroms, und

Fig. 6

ein Diagramm mit den Stromverläufen im Strompfad, im Ableitpfad und über die Ausgangsklemme des Sicherungsautomaten.

Show it

Fig. 1

a circuit diagram with a fuse arrangement, which is arranged between a multi-phase power supply and a multi-phase load,

Fig. 2

a detailed view of the diagram from Fig. 1 in which only a circuit breaker of the fuse arrangement is shown,

Fig. 3

a detailed view of the diagram from Fig. 2 , in which the in Fig. 2 shown circuit breaker is shown in detail,

Fig. 4

a diagram of a load current profile when using a conventional circuit breaker in the detection of an overcurrent,

Fig. 5

a diagram of a load current profile when using a circuit breaker according to the invention in the detection of an overcurrent, and

Fig. 6

a diagram with the current curves in the current path, in the discharge path and via the output terminal of the circuit breaker.

The FIGS. 1 to 3 The fuse arrangement 1 is connected on the input side to a polyphase power supply 3 or supply line, each phase 4, 5, 6 being secured by a circuit breaker 2.

Each automatic circuit breaker 2 is designed to protect a phase 4, 5, 6 and has an input terminal 7, an output terminal 8 and a discharge terminal 9. The circuit breakers 2 are connected to their input terminal 7 each with a phase 4, 5, 6 and with its output terminal 8 to a load 10. The load 10 is a multi-phase load, which is exemplified here by an electronic switching device. The discharge terminals 9 are each connected to a ground 11.

In the circuit breaker 2, the input terminal 7 and the output terminal 8 are electrically connected via a current path 12. In the current path 12, a separator 13 and a monitoring device, 14 are arranged. The disconnecting device 13 is designed as a normally closed contact in order to interrupt the current path 12 during an actuation. The monitoring device 14 is designed to monitor a current in the current path 12.

The circuit breaker 2 also has a discharge path 15 which is connected at its one end to the current path 12 between the separator 13 and the output terminal 8 and at its other end to the discharge terminal 9. In the discharge path 15, a connecting device 16 is arranged, which is designed to connect through the discharge path 15 in an actuation. Accordingly, the connecting device 16 is designed as a closer.

The separating device 13 and the connecting device 16 are coupled to a common operation with a coupling device 17. The coupling device 17 in this embodiment is a mechanical coupling device 17. The coupling device 17, an actuating element is connected, which is also actuated upon actuation of the coupling device 17, so that the operation from the outside, i. from outside the circuit breaker (2), recognizable. In addition, a manual actuation of the coupling device 17 and thus separating device 13 and the connecting device 16 can be performed by the actuating element.

The monitoring device 14 is executed, upon detection of an overcurrent, the separation device 13 and the To operate connecting device 16 via the coupling device 17. The monitoring device 14 has a bi-metal switch 19 for continuous current monitoring in order to detect an excessive line current as an overcurrent. In addition, the monitoring device 14 has a magnetic switch 20 with a magnetic quick release as short-circuit protection for fast operations to monitor a short-circuit current as overcurrent. In the magnetic switch 20, a magnetic field is generated by the overcurrent, so that with the aid of a relay coil and armature actuation of the coupling device 17 takes place.

The FIGS. 4 and 5 schematically show the breakdown of the current I _k through the output terminal 8 for a conventional circuit breaker and for a circuit breaker 2 of the described embodiment. The current has fallen in the conventional circuit breaker only after about 4 ms to a safe level, while this is already the case with the circuit breaker 2 described here after about 0.2 ms.

Fig. 6 shows the operation of the circuit breaker 2 in detail. A current I _c flowing through the input terminal 7 is detected by the monitoring device 14 as an overcurrent, whereby at the time t = 0s an actuation of the separating device 13 and the connecting device 16 via the coupling device 17 is triggered. Accordingly, the current path 12 is interrupted by the separator 13, and the discharge path 15 is connected through the connecting device 16. The switching of the disconnecting device 13 and the connecting device 16 in this embodiment takes about 0.2 ms. During this time, the entire current I _{c flows over} as output current I _k the output terminal 8 and thus the load. At time t = 0.2 ms, the discharge path 15 is connected through, so that a current I _c1 at the discharge terminal 9 is already approximately equal to the current I _c through the input terminal 7. Accordingly, the current I _k breaks down via the output terminal 8 and is already at time t = 0.4 ms approximately zero.

As in Fig. 1 can be seen, the circuit breakers 2 are mechanically coupled to each other via a coupling element 21. As a result of the mechanical coupling, the automatic circuit breakers 2 can mutually transmit an actuation by their respective monitoring device 14 to the other automatic circuit breakers 2. The coupling element 21 in this embodiment is designed as a separate component, which is connected in a manner not shown here in detail with the actuators of the three circuit breakers 2. The coupling element 21 is designed with a manual actuator 22 for manual actuation of the coupled automatic circuit breakers 2. The hand actuator 22 is designed for manual actuation both for the common disconnection and interconnection of the current paths 12, wherein the manual operation is recognizable from the outside via the hand actuator 22.

In an alternative embodiment, not shown here, the fuse arrangement 1 is designed as an integral device. LIST OF REFERENCE NUMBERS fuse assembly 1 breaker 2 Power supply, supply line 3 phase 4 phase 5 phase 6 input terminal 7 output terminal 8th guard terminal 9 load 10 Dimensions 11 current path 12 separating device 13 monitoring device 14 discharge path 15 connecting device 16 coupling device 17 Bimetal switch 19 magnetic switches 20 coupling element 21 manual actuator 22

Claims (11)

1. An automatic circuit breaker (2) for protecting a phase (4, 5, 6), comprising
   an input terminal (7),
   an output terminal (8),
   a current path (12), which electrically conductively connects the input terminal (7) and the output terminal (8),
   a disconnection apparatus (13), which is arranged in the current path (12) and which is configured to interrupt the current path when actuated,
   a discharge terminal (9),
   a discharge path (15), which is connected at one end thereof to the current path (12) between the disconnection apparatus (13) and the output terminal (8) and which is connected at its other end to the discharge terminal (9),
   a connection apparatus (16), which is arranged in the discharge path (15) and which is configured to connect through the discharge path when actuated, and
   a monitoring device (14), which is configured to monitor the current in the current path (12) and, when an overcurrent is identified, to actuate the disconnection apparatus (13) and the connection apparatus (16) so that the currents during the switching of the disconnection apparatus (13) after the switching of the connection apparatus (16) are discharged via the discharge terminal (9), wherein
   the monitoring device (14) is configured to carry out permanent current monitoring and short-circuit current monitoring.
2. The automatic circuit breaker (2) according to claim 1, characterised in that
   the monitoring device (14) has a bimetal switch (19) for permanent current monitoring.
3. The automatic circuit breaker (2) according to either one of claims 1 or 2 characterised in that
   the monitoring device (14) has a magnetic switch (20) for short-circuit current monitoring.
4. The automatic circuit breaker (2) according to any one of the preceding claims, characterised in that
   the automatic circuit breaker (2) has a coupling device (17), to which the disconnection apparatus (13) and the connection apparatus (16) are coupled for joint actuation, and
   the monitoring device (14) is configured to actuate the disconnection apparatus (13) and the connection apparatus (16) via the coupling device (17).
5. The automatic circuit breaker (2) according to any one of the preceding claims, characterised in that
   the automatic circuit breaker (2) has an actuation element, which, in the event of actuation by the monitoring device (14), is actuated so that the actuation is identifiable externally.
6. The automatic circuit breaker (2) according to claim 5, characterised in that
   the actuation element is configured to perform a manual actuation of the disconnection apparatus (13) and of the connection apparatus (16).
7. A circuit breaker arrangement (1) comprising a plurality of automatic circuit breakers (2) according to any one of the preceding claims for use in a multi-phase supply line (3), wherein
   each phase (4, 5, 6) is protected by an automatic circuit breaker (2), and
   the automatic circuit breakers (2) are coupled to one another.
8. The circuit breaker arrangement (1) according to the preceding claim 7, wherein
   the automatic circuit breakers (2) are mechanically coupled to one another.
9. The circuit breaker arrangement (1) according to the preceding claim 8, wherein
   the automatic circuit breakers (2) have an actuation element for manual actuation of the disconnection apparatus (13) and the connection apparatus (16), and
   the automatic circuit breakers (2) are mechanically coupled to one another via a coupling element (21).
10. The circuit breaker arrangement (1) according to the preceding claim 9, wherein
    the coupling element (21) has a manual actuator (22) for manually actuating the coupled automatic circuit breakers (2).
11. The circuit breaker arrangement (1) according to any one of the preceding claims, wherein
    the circuit breaker arrangement (1) is configured as an integral device.

Images