EP1336185B1 - Electrical breaker device for current leakage, current overload and short-circuit protection - Google Patents

Description

The invention relates to an electrical switching device for fault, overcurrent and Short-circuit current protection according to the preamble of claim 1.

The currently known electrical switching devices such as disclosed in DE 1 538 370 when used for overcurrent and Short-circuit current protection should be used, a thermal release in the form a bimetallic strip that deflects when an overcurrent occurs and thereby Switch lock unlocks, causing a contact point in the switchgear to remain open becomes. An electromagnetic release is provided for short-circuit protection Has magnetic core and a movable magnet armature, which are surrounded by a coil with which the contact point is opened directly on the one hand and a on the other Switch lock is unlatched, so that in this case the contact point remains open is. Two triggers must be provided for both triggering methods, namely the thermal one Trigger and the electromagnetic trigger.

If the switching device is to switch off a fault current, then this switching device has a converter through which the current path (network conductor) is passed; a secondary winding is arranged on the converter, which is based on an electromagnetic Trigger activated in the form of a holding magnet or a blocking magnet is that on a. The key switch acts so that the contact point is opened permanently.

Three triggers must be provided for all three protective measures, one in a switching device the short circuit and overcurrent is detected; residual current protection takes place in its own residual current circuit breaker. This arrangement or assignment of individual switchgear for the corresponding protective measures is complex.

The object of the invention is to provide a switching device of the type mentioned create, which is simplified compared to the known switching device.

This object is achieved according to the invention by the features of claim 1.

According to the invention, only one trigger is provided in a switching device is suitable for all of these protective measures. For this there are two permanent magnets with their poles of the same name, provided, whereby between the mutually pointing eponymous poles of permanent magnets, of which the one is fixed and the other movable, one with one of the permanent magnets connected core made of magnetic material is provided. The permanent magnets and the core are at least partially surrounded by at least one coil formed by a fault current, overcurrent or short-circuit current is applied, so that at Occurrence of a current flow in the at least one coil the magnetic field such is changed that there is a relative movement of the moving part, the direct or transmitted to the contact point via the key switch.

One exploits the effects of a model with which forces in fusion processes can be simulated, see Am.J. Phys. 62 (9), September 1994, pp. 804 to 806. In the model described there, the moving parts pull when they are Sign a distance of approx. 2.6 mm, with a maximum force of 17 N, against repulsive forces at a distance greater than 2.6 or 3 millimeters Act.

With the coil, the magnetic shown in Fig. 2 of the reference Fields are influenced so that in the event of a current through the coil, attractive forces overcome and only the repulsive forces act. In that the movable If a part is pushed off with a relatively high force, a key switch can be released or a contact point can be opened immediately. If the coil is short-circuit current flows through, the arrangement acts as a short-circuit opener or short-circuit release, and when an overcurrent flows through the coil, it heats out the core magnetic material, and, if it consists of such a material, the saturation at higher temperatures than overcurrent releases. If the coil If the fault current flows through it, the release acts as a fault current release.

According to a preferred embodiment, a first coil is provided which has a Energy storage circuit connected to the secondary winding of a current transformer is, so that a fault current is detected.

According to a further preferred embodiment, a second coil is provided, which is in the current path of the switchgear and which acts as a short circuit protection and overcurrent protection coil drives the movable part of the trigger according to the invention.

This creates a release with two coils that performs all the functions of a fault current - and circuit breaker can perform.

To avoid wastage, the trigger is assigned a yoke as a conclusion, the fixed part is attached to the yoke.

According to a special embodiment of the invention touch in the idle state the magnets and the magnetic material and are when current flows through the Coils repelled.

According to a further embodiment of the invention, the permanent magnets in Hibernation kept at a distance and the magnetic fields act so that they Current flow through the coil to make the magnets tighten.

To guide the two parts, i.e. the movable and the fixed part against each other, are both parts of a coil body made of non-magnetic material surrounded and led.

At least one of the contacting surfaces of the two parts can be according to the invention be coated with a non-stick layer. This ensures that gluing processes be avoided between the moving parts.

Using the drawing, in which an embodiment of the invention is shown, the invention and further advantageous refinements and improvements the invention are explained and described in more detail.

It shows: The single FIG. 1 shows a sectional view in a schematic representation through a Trigger.

A trigger 10 has a yoke 11 which is U-shaped with a web 12 and two Legs 13 and 14 extending perpendicularly thereto are provided. On the leg 13 is attached by means of a rivet 15, a first permanent magnet 16 with the North pole N on leg 15. A second permanent magnet 17 is assigned to trigger 10, the north pole N of which is adjacent to the leg 14, whereas the South pole S of the second permanent magnet 17 the south pole S of the first permanent magnet 16 is opposite. Between the two permanent magnets 16 and 17 there is a core 18 made of magnetic material, the permeability of which Temperature is so dependent that the core 18 saturates at elevated temperatures goes. In this embodiment, the core with the second permanent magnet 17 magnetically connected. The two permanent magnets 16 and 17 together with the core 18 are surrounded by an inner bobbin 19, for example consists of plastic or the like. There is one wrapped around the inner bobbin first coil 20 and around this coil is surrounded by a second coil body 21, on the outside of which a second coil 22 is wound. The inner coil or first Coil 20, with its connections 23 and 24, has an energy storage circuit 25 connected, the input of which is connected to the secondary winding 26 of a converter 27 is, the primary winding is passed through a current path 28 in which a contact point 29 is located. The second coil 22 is located in the current path 28 the ends of the current path 28 are connected to terminals 30 and 31.

A plunger 33 connects to the north pole N of the second permanent magnet 17 acts via a switch lock 34 and, on the other hand, directly on the contact point 29, the lines of action are shown in dashed lines. The plunger 23 is made of non-magnetic Material and has a shoulder 35 which against the inner surface of the yoke 14, drawn in the off state, comes to rest so that the movement of the second permanent magnet 17 is limited to the core 18.

If a fault current is detected via the converter 27, then the energy storage circuit 25 charged and generated a suitable magnetic field via the coil 20, so that the two parts touching separate and due to the repulsion effect the pole of the same name in the triggered position, see Fig. Thereby the contact point 29 is permanently opened via the switching lock 34.

If an overcurrent occurs in the current path 28, the core 18 heats up; thereby changes the permeability of the core 18 so that it goes into saturation and then magnetically seen is air. This causes the two permanent magnets to collide from and via the switching lock 34, the contact point 29 is opened permanently.

If a short-circuit current flows in the current path 28, then the magnetic field is generated via the coil 22 changed so that the poles repel and the plunger 33 both directly and acts on the contact point 29 via the key switch.

The configuration according to the invention thus serves as a trigger for a fault current, Overcurrent and short circuit release. This is achieved by assigning the two Permanent magnets with the core 18 inside the coils 20 and 22.

Claims (11)

1. Electrical switching device for a fault-current, overcurrent and short-circuit current protection, having a contact point (29) in the current path (28) and having a switching mechanism (34) for permanently opening the contact point, and having means for detecting the fault current, the overcurrent and the short-circuit current, characterized in that the means comprise two permanent magnets (16, 17), whose like poles are opposite one another, with a core (18), which is permanently connected to one of the permanent magnets (16, 17) and is composed of magnetic material, being provided between the like poles of the permanent magnets which point towards one another and one of which is fixed and the other is guided such that it can move, in that the permanent magnets (16, 17) are at least partially surrounded by at least one coil (20, 22) through which a fault current, an overcurrent or a short-circuit current flows, so that, when a current flow occurs in the coils, the magnetic field is changed such that a relative movement of the moving part takes place, and is transmitted directly or via the switching mechanism to the contact point.
2. Device according to Claim 1, characterized in that the core (18) is permanently connected to the moving second permanent magnet (17).
3. Device according to Claim 1 or 2, characterized in that a first coil is connected to one end of an energy storage circuit (25), whose other end is connected to the secondary winding (26) of a current transformer (27), such that a fault current is detected so that the magnetic field of the release is changed.
4. Device according to one of Claims 1 to 3, characterized in that a second coil (22) is provided, which is located directly in the current path (28) and detects overcurrents or short-circuit currents.
5. Device according to one of the preceding claims, characterized in that the core (18) is composed of a material which changes its magnetic characteristics, in particular its permeability, as the temperatures rise, and which enters saturation at increased temperatures.
6. Device according to one of the preceding claims, characterized in that a yoke (11) is provided as a magnetic return path, and in that the stationary part (16) is attached to the yoke.
7. Device according to one of the preceding claims, characterized in that, in the rest state, the magnets touch the core and are attracted to it, and are repelled when a current flows through the coils.
8. Device according to one of Claims 1 to 6, characterized in that, in the rest state, the magnets are held spaced apart and are attracted when a current flows through the coils.
9. Device according to one of the preceding claims, characterized in that the magnets together with the core are surrounded and guided by an inner coil former composed of nonmagnetic material.
10. Device according to Claim 9, characterized in that the inner coil (20) is surrounded by a second coil former (21).
11. Device according to one of the preceding claims, characterized in that at least one of the touching parts is coated with an anti-adhesion coating.

Images