LU79817A1 - Fault current protection switch - Google Patents

Description

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Luxembourg, June 15, 1978 Residual current circuit breakers

Applicant: Nicolas GATH, 15 rue Joseph Tockert, Luxembourg

The invention relates to a residual current circuit breaker for protecting people from electric shocks.

It is a known disadvantage of the residual current circuit breakers that are common today that they are

Occurrence of a direct current fault current does not react to this and also their sensitivity

AC fault current is reduced. In a

Patent application from August 22, 1977 »No. 78012, in Luxembourg i it has been proposed that the operating current

K

* Leading conductors are wound as coils on a core made of magnetically conductive material - 2 - and which itself is a coil consisting of several turns. When a fault current flows, a magnetic flux φ-ρ, which is referred to below as fault current magnetic flux, is generated in this core, the magnetic voltage of which is relatively high and can thus activate a blocking magnetic release. In a supplementary application dated 02.09-1977 (· v in Luxembourg, No. 78075, a special embodiment of a blocking magnet release has been proposed. The residual current magnetic flux is conducted via an intersection zone, through which the magnetic flux also flows, which holds the armature of the release. The latter is called the tripping frame sustaining magnetic flux in the following.

The invention has for its object to reduce the magnetic voltage required for the response of the blocking magnet release and thus to reduce the number of turns of the coils formed from the operating current-carrying conductors or the number of turns of the coil made of magnetically conductive material.

The object is achieved in that the crossing zone is dimensioned such that the length of the path that the residual current magnetic flux within the

Crossing zone, is less than the length of the path, the trip frame retaining magnetic flux: v / 7 - 3 - ϊ ·

II

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,; passes through within this zone, or that at! | several crossing zones

The two parts of the conductor that collide in the crossing zone should be aligned, | i h ij as should the two parts of the conductor 1φ ^ that collide in | i "the crossing zone.

i <

Ij That section of the ladder should then be ij | v, which can be found in the bundle »i! the escape lines of the conductor Ιφ ^ and the conductor 1φ ^ ί.

i;] In Figure 1, this crossing zone is a cube, because i jj the cross sections of both conductors are square and the same; are big. The surface (3 in FIG. 1, dotted: drawn) is one of the six outer surfaces of this I cube. It borders the latter against the left ladder part ^ FL (½) äs ißf'te1,3 Ιφρ (l) i another opposite surface (4) against the right ladder part | (1-ß) of the conductor Ιψρ (1). Another surface: -® <[> ho äer ^ lateral surfaces of the cube borders this> against the upper part of the conductor 1φ ^ 0 (2Q) of the conductor 1φ ^ (2), j another surface below (6) of the

Cube delimits this from the lower conductor part Ιφ ^ (2U) of the conductor. The path length of the residual magnetic flux φρ in the intersection zone is given by the distance between the surfaces (3) and F ^ R (4), i: j, Sf - 4 - ï t

The path length w (j) il of the release armature holding magnetic flux in the crossing zone is given by, the distance between the I surfaces (5) md ^ hu (6). In the exemplary embodiment shown in FIG. 2, it is approximately four times smaller than w ^ *. However, in order that the same cross section as in FIG. 1 is available for the magnetic flux φ ^ in FIG. 2, its dimension Mg is in the direction perpendicular to the plane of FIG two crossing conductors have been enlarged.

Why the specified measure brings the desired effect is also to be explained theoretically in the following. Assume there is no fault current flowing so zero. Then the magnetic circuit, leads, can be designed so that part of the

Crossing zone is in a state that can be called magnetic saturation. Suppose that a fault current now occurs, which has the switch-off current, and the two magnetic circuits are dimensioned such that the magnetic voltage caused by the fault current between the surfaces F ^^ and F ^ p-jj has the same value in an arrangement according to FIG. 1 as in one according to FIG. 2. Then the magnetic field strength, which is caused by the fault current and runs in the direction of the conductor Ιψ ^, is considerably greater in FIG. 2 than in FIG. 1.

This additional field strength H ^, //! , i - 5 - the strength of the magnetic flux density does not change very much, since the magnetic material in the crossing zone had already been in a saturated state before. However, a new direction of the Eluss density arises parallel to the resultant of the two magnetic field strengths Eg, which are effective at the respective point, and so that the component of the magnetic Eluss, which goes from 1φ ^ 0 (2Q) to (2U) in Eigur 2 approximately drops to a quarter. In contrast, in Eigur 1 the two Eeld strengths Hp and largely have the same value. The resultant forms an angle with an average value of 45 degrees. The component still effective in the direction of ^^ is therefore only reduced by the factor sin 45 ° = 0.7, i.e. by considerably less than in an arrangement according to Eigur 2.

According to Eigur 2, less magnetic voltage is required to actuate the trigger. Under certain circumstances it is possible to do without the core K as a coil with more than one turn. Depending on the demands that are made with regard to the maximum permissible dimensions of a circuit breaker, the measure of the present patent application can therefore be applied and the leakage generated in a single turn of a magnetic conductor can be passed directly to the blocking magnet release. In addition, the measure can also be applied to a trigger whose crossing îÆ \ - 6 - zone has a small hole in the middle perpendicular to the plane of the two flow conductors (1) and (2).

If you make this hole bigger and the river conductors narrower, you finally get a shape as shown in Figure 5 of the patent application dated 02.09.1977 No. 78075 »Luxembourg.

In the previous explanations, the simplifying hypothesis is used that the lines of force are bundled in parallel in the crossing zone.

In reality, however, they partially evade this zone, as shown in Figure 3. This evasion is largely prevented if, as shown in FIG. 4, one or more slots are made in the flow guide. The level of this

Slits is perpendicular to the plane where the river guides and intersect. It is also parallel to the residual current magnetic flux conductor Ιφρ. Such a slot does not go into the crossing zone. Thus, the slot (11) in FIG. 4 extends from the area which delimits the crossing zone to the left, to the point (12) further to the left, which from a certain point of view

The minimum depth should be so that a line of force that emerges from the crossing zone near Ρφ ^ 0 must make a long detour before it reaches the uφ ^ at F ^ u. The trigger armature retention magnetic flux which escapes from the crossing zone is therefore greatly reduced. If one imagines that the slots are continued over the entire length of the conductor ΙΙΐφ-ρ, up to where the conductor comes into contact with from the right side, the conductor Ιφ-p is separated into 4 conductors. As is known, for a homogeneous magnetic field H = —j—, that is to say the magnetic field strength H is equal to the magnetic voltage U divided by the path length 1. If the voltage IL · caused by the error current ip at the borders of the crossing zone is now the same £ of the magnetic voltage, which is caused by φ ^ at the interfaces of the crossing zone, while the path length of the lines of force for the river is four times less than for the river, the field strength Hp caused by iw is four times greater than the field strength caused by the release armature magnetic flux% ·

By dividing the conductor Ιφρ into four parallel conductor sections (or into four almost completely separate parallel conductors), the crossing zone can also be considered as divided into four sub-crossing zones. These are in series for the φ ^ flow and only a quarter of the U ^ l voltage is effective in each crossover zone. For the flow φρ these crossover zones are parallel and it is the whole voltage Um

X

effective in each crossover zone.

κ ·! - 8 -

Figure 5 shows a further embodiment.

Designating 5a as the front view is 5h! the view to the left. FIG. 5c represents the top view obtained by turning the figure -I 5h 90 degrees towards the observer. These ! Execution can be thought of as arising from FIG. 4 ·: The number of turns of the fault current i I flux conductor has been reduced to 1, and this! The entire length of the conductor, except in the crossing zone, has been divided into 4 separate conductors by the three slots. The manufacture of such a magnetic conductor system does not require welding if seamless tube is used as the starting material.

The pipe should have the outside diameter D given in the drawing. The clear width should be d. The three slots (31, 32, 33) are cut in with a sawing machine ^ such that each of the rings (36, 37, 38, 39) thus created is still connected to the other rings by a narrow web (41, 42, 43) is. In the extension of this row of webs, a narrow strip of about 7 cm in length (scale 1: 1 provided) is left, which would extend downwards at (44) in FIG. 5 a. This is bent twice at a right angle below (44) so that the two corners (46) and (47) are created, resulting in the U-shape of the holding magnet. The conductors (R, S, f, Mp) which supply the mains power to the consumer system (also called conductors carrying operating current) are through the 4 rings ./iWi/fi) - 9 -.

(36, 37, 38, 39) passed through (shown in Fig. 5 b). The latter are the fault current flow conductors L <f> F. The trigger armature retaining magnetic flux runs from the cord pole of the permanent magnet (30) via the left leg (25) in FIG. 5b, the armature (19), the right leg (24) to the south pole of the permanent magnet (30) . The leg (24) consists of the intersection-free lower part, the intersection zones (26, 27, 28, 29), as well as the connecting webs (41, 42, 43) between the intersection zones, and the short upper inflection-zone-free part. The cross section available for the release armature holding magnetic flux is narrowed at three points by the narrow connecting webs (dimension b is quite small) and thus counteracts a strong thinning of the lines of force (as shown in FIG. 3) reinforced. A further improvement in the blocking effect is achieved if the thickness of the rings, which is referred to as Di in FIG. 5b, is chosen, as a result of which, as in the shortest

Claim 3 specified, the length of the 'path of the tripping retaining magnetic flux within the crossing zone is large in relation to the length of the shortest path within the Krüuzungs zone, w.r \ -lies residual current magnetic flux. It can be seen in FIG. 5a φ ersichtlich that the shortest length of the path w ^ of the release armature holding magnetic flux is equal to the thickness Di of a ring and that the shortest length of the Æiï 'I' I. - 10 -: The path νίφρ within the crossing zone is the same

Width b of the "connecting bar left during sawing.

Instead of a solid tube, you can also use a tube body that consists of several (2, 5 »4. ·) Into each other! ’There are pipes pushed in that fit tightly together without play. When slitting you get 1 ’several concentric rings. You can even use a so-called band core, which geometrically also represents a tube. (A farmer, more precisely a ring band core, can be obtained by placing a band, for example 0.1 mm thick and about 40 mm wide, on a mandrel of 12 mm diameter rolled up into a roll until a diameter of about 17 mm is reached. The resulting tube body then has a length of 40 mm, an outer diameter of 17 mm and a clear width of 12 mm In question, in which a wire of about 0.2 mm forms the cutting tool. Electrical runs are created between this wire and the material to be cut, which remove the material.

According to a known packaging method, which is used for endlessly * soldered band saw blades, it is possible to produce a wreath from such a band saw, for example 6 * 28 m in length, which would form a circle of 2 m in diameter. which consists of 3 turns and has a diameter of 0.66 m. If one now selects an approximately 5 times larger IM dimension for D in FIG. 5, while the wall thickness ws of the ring remains the same, it is possible by suitable bending to form a ring in which 3 turns of each of the 4 rings are contained. It should be advantageous to use the rings before bending. Using a wire »to bundle it into a single ring. (The wire would be attached in the same way as you would normally wind a coil around the entire circumference of a toroidal core). This ring-shaped bundle is now bent and shaped as a whole, so that the new ring-shaped body that is formed consists of three turns of the ring bundle. There are then mainly magnetic conductor pieces next to one another which have the same magnetic potential, and the leakage flux from one turn to an adjacent one is reduced. After winding, the wound wire can be removed.

By passing direct current or alternating current through the magnetically conductive core material, its apparent permeability can be improved, that is to say the hysteresis loop becomes narrower. In FIG. 3 one would connect a point of a ring, which is close to the reference numbers 36, 37, 38 and 39, to the one output of a current source and a point of the magnetic leg, close to the reference number 46, to the other output of this current source. The generated field strength H

(7 / Ψ'ΐ / ^ - 12 - ï stands in the middle of a ring perpendicular to the field strength Hp generated by a fault current. The field strength required for magnetization of anisotropic material in the preferred direction is lower when there is a field strength perpendicular to the preferred direction. (See introduction in the theoretical electrical engineering, 10th edition Springerverlag by K. Küpfmüller * 1973, pages 252-253) using anisotropic

Material that has a higher permeability in the direction in which the magnetic field strength caused by a fault current in a ring would then be particularly advantageous.

- Λ J

/ - v 7 / y «

Claims (3)

1. Residual current circuit breaker for protecting cles people from electric shocks, with a core made of magnetically conductive material, which is a magnetic conductor that is chained in one or two or more turns to the electrical conductors that supply the electrical system to the consumer system, characterized in that that the magnetic flux φ ^ runs over a conductor (2) in which there are one or 2 or more crossing zones, where a flux φ · ρ generated by a fault current in a magnetic conductor Ιφρ (1) crosses with the flux, whereby φ ^ represents the flux which is caused by a permanent magnet (30) and which normally holds an armature (19) belonging to the trigger (18) and thus prevents the circuit breaker from being switched off, where φ ^, a magnetic flux caused by a fault current in Conductor L ^^ (1) referred to, whereby in the crossing zone, the direction with the direction markedly differs from 0 degrees forms an angle, this angle preferably being equal to • 90 degrees, the direction being that ✓ / * line of force of the river which crosses the crossing zone by the shortest path \ νψ ^, where, if φ ^ = 0, the direction Dj , is the direction of the line of force of the river which crosses the crossing zone on the shortest path w (j) ^. · 2. Residual current circuit breaker according to claim 1, ge * indicates that in addition to the conductor L (J) F one or two or more such residual current flow conductors are arranged, each of these conductors forming a crossing zone of the type described with the Auelöserankerhaltemagnetflußleiter L ^. 3. Residual current circuit breaker according to claim 1 or 2, characterized in that the length of the path w (j) ji is large in relation to the length of the path w ^. Jip- '// / 7 »