WO2007090820A1

WO2007090820A1 - Device for triggering an electric switchgear

Info

Publication number: WO2007090820A1
Application number: PCT/EP2007/051089
Authority: WO
Inventors: Detlef Koch; Norbert Leicher; Aldin Omanovic
Original assignee: Moeller Gmbh
Priority date: 2006-02-08
Filing date: 2007-02-06
Publication date: 2007-08-16
Also published as: DE102006005697A1

Abstract

A thermo-magnetic triggering device for electromagnetic switchgears is proposed. Such triggering devices are composed of a bimetal strip (for the purpose of overcurrent triggering) and a quick release switch or short-circuit trip which has a magnetic yoke, magnetic armature acting on the switching lock and an exciter winding through which current flows. The triggering device is intended to be constructed from the smallest possible number of parts. The invention consists in the fact that the bus bar 10 is formed from a planar piece of material and on it the following are also formed: a current feed connection 11, a clip 12 for passing on the current to a switching contact of the switch, at least one attachment point 15 for the bimetal strip 21, an attachment point 14 for the magnetic apparatus 40, and attachment webs 16 for securing and mounting the device in a switch housing. A heating conductor 13 which is formed integrated in the bus bar and which has a predetermined resistance value serves to generate the heating power for heating the bimetal strip 21 which bears snugly against the bus bar 10.

Description

Device for triggering an electrical switching device

Technical area

The invention relates to a device for triggering an electrical switching device according to the preamble of claim 1. Such tripping devices are used in circuit breakers or circuit breakers for motors, lines, generators and / or transformers. They have this Hauptschalter- and separator properties with a high tripping accuracy, the limitation of the overload and

Short-circuit currents is adjustable. This can be current-dependent or delayed. An electromagnetic quick release (short-circuit release) switches instantaneously as soon as noticeably higher currents than the specified limit currents occur.

State of the art

Adjustable delay times of short-circuit releases are typically in the range of 0 to 100 ms. The fields of application of known circuit breakers include currents of up to a few 1000 A, with high-performance switches also coping with large short-circuit currents of up to 100 kA. Such switches can be constructed in three or four phases. The thermo-magnetic release devices used in this case consist of a bimetallic strip (for the purpose of overcurrent release) and a quick release or short-circuit release, which has a magnetic yoke, an armature acting on the switch lock and a current-carrying exciter winding. It is known to place the bimetallic strip in the current path and to pass the unidirectional bimetal strip through the magnetic yoke and to use this current as excitation for the electromagnetic quick release. Because of the high currents occurring in the event of a short circuit and the associated high forces between magnet armature and magnetic yoke, this is sufficient since this arrangement already forms half a turn of the excitation. From DE-PS 9 46 826 a thermo-magnetic release device is known in which a U-shaped bimetal is used. A magnetic yoke encloses a leg of the bimetal. The other leg of the bimetal is passed outside the magnetic yoke. Another magnetic yoke surrounds this leg. The guided leg contributes to increasing the magnetic flux, which improves the tripping sensitivity of the short-circuit release. An additional turn of flat material is also passed through the yokes and electrically connected in series with the bimetal. The use of a similar - also U-shaped - bimetal - is known from DE-PS 875063.

A bimetallic element known from US Pat. No. 2,629,726 (FIG. 2) has a likewise U-shaped electrical resistance which is connected in parallel with the bimetallic element, ie functions as a shunt. Thus, a bimetallic element can be used in the thermal release for various trip areas by causing a weakening of the current flow in the bimetallic element.

In yet another embodiment, a bimetallic trigger with shunt connected in parallel is described (DE 195 16 723 A1), which consists of a large number of individual parts. To use each of the known designs, an adjustment and / or calibration of the adjustment to a certain triggering range is necessary. In the majority of parts, manufacturing tolerances and thus the expense of setting operations add up.

Presentation of the invention

The invention is therefore based on the object to propose an embodiment of a device for triggering switching devices, which consists of a small number of individual parts.

Starting from a device of the type mentioned, the object is achieved by the features of the independent claim, while the dependent claims advantageous developments of the invention can be found. This results in the advantage that compared to the known tripping devices, the number of individual parts or on part versions for the production of the tripping devices is reduced. Thereafter, a lesser effort in production (storage, assembly) can be operated.

The core of the invention is that the busbar is formed from a flat piece of material, and further formed thereon: a power feed terminal, a tab for current transmission to a switch contact of the switch, at least one attachment point for the bimetallic strip, an attachment point for the magnetic apparatus, and fixing webs for fixing and mounting of the device in a switch housing.

Only a few operations are required for completion and installation in a switch housing. To the power line tab to solder a conductor wire, which is already connected to the movable switching contact of the switch. After this soldering operation, the device is inserted into a groove of the housing, wherein webs on the busbar present, which slide into the groove fitting.

A particular advantage of the invention is that the functional features are more or less accurately predetermined by the precise production of the parts before installation of the device in a switch housing and the subsequent Endjustage consists only in a fine adjustment.

Advantageous embodiments are the following:

The bus bar is made of a flat material, bent in a U-shape, and the current feed terminal is projecting at right angles from a first U leg and the current conductor tab is formed at right angles to a second U leg.

The magnetic armature and magnetic yoke existing magnetic apparatus is mounted in the space between the two U-legs. The bimetallic strip is fastened on the outside of the second U-leg. - A -

The design of magnetic yoke and magnet armature is such that they enclose the heating conductor section and the bimetal strip applied there.

The heating conductor section, which is formed in quasi-integrated fashion in the current conductor, preferably consists of two parallel strips of material of predetermined conductivity by choice of an alloy. The section is created prior to the formation of the bus bar by punching a predetermined length and width slot. The Heizleiter section can consist of only a single strip of material. The size of the heating element resistance is assigned to the rated current of the switching device.

The fastening webs for fixing and mounting the device in a switch housing are formed on the first U-leg.

The at least one attachment point for the bimetallic strip and the attachment point for the magnet apparatus are each as a rivet stub and the current conductor tab is designed as a stranded connection. The rivet stumps can be produced by embossing from the sheet material forming the busbar. After placing the bimetallic strip riveting is done with a riveting tool. Preferably, an opening (see Fig. 2) is recessed in the U-legs opposite the attachment point, which allows access to the Nietstumpf. In the same way, the magnet apparatus is attached.

The parts of the magnet apparatus each have two sections arranged offset in height, wherein the sections arranged below form yoke and armature and a respective arm for holding a tension spring is formed on the sections arranged at the top.

The magnetic flux of the magnet armature, the size of the air gap and the spring constant of the armature spring determine the tripping range of the quick release.

The operative connection of the device with the switching mechanism of a switching device is that the overcurrent release and / or the magnet apparatus is in force-locking contact with a triggering bridge acting on the switching mechanism. The formation of such an operative connection is (in variants) known from some disclosures of the Applicant (DE 314981 1 A1, DE 19916988 A1) and is claimed here as a preferred embodiment of the invention.

At the trip bridge bevels are present, to which force the cantilever of the magnet apparatus and the adjusting screw of the bimetallic strip create. The actuation of the trip bridge (by bending the bimetallic strip or by closing the magnet apparatus) triggers the pawl of a force accumulator via a lever arrangement, which in turn opens the lock of the switching device.

The fine adjustment of the trigger device is carried out after installation in a device housing and after assembly with the mentioned parts of the switching mechanism (trip bridge, latch, power storage).

Brief description of the drawings

Further details and advantages of the invention will become apparent from the following, explained with reference to figures embodiment. Show it

Figure 1A, 1B: two perspective views of the device;

Figure 2: a perspective view of the busbar;

FIG. 3 is a perspective view of the magnetic apparatus;

FIG. 4 shows a representation of a plurality of tripping devices in the installed position in a switch.

Best way to carry out the invention

FIGS. 1A and 1B show, in perspective view, a triggering device 100, consisting of a thermal overcurrent release 20 and an electromagnetic quick release 40, which are arranged next to one another in a corresponding number in the presence of a plurality of phases in the switching device. The power connections 1 1 point outwards from the switching device, the connections 12 are inside the switching device; are preferably with a strand 17 soldered and point in the interior - in the direction of the contacts - a switching device. The current flow is indicated by the current arrows i (see FIG. 2). The position of several devices 100 next to one another is shown in FIG. 4.

The tripping current flows through the busbar 10, in particular through the section 13, which is designed as a conductor with a predetermined resistance value for generating the heating power for heating the bimetallic strip. The production of the busbar is done by punching a flat strip with immutable external dimensions. The final shape is created by bending and folding. The busbar 10 is substantially U-shaped in the central region, formed by the two - approximately parallel - legs 10A and 10B. The leaf-shaped bimetallic strip 21 is riveted to the busbar at the point (Nietstumpf 14 on the leg 10B) and is the busbar (on the leg 10B) tight and flat.

The magnet apparatus 40 is likewise fastened to the busbar, so that the triggering current likewise effects the magnetic flooding of the rapid release consisting of a U-shaped magnet yoke 51 and a U-shaped magnet armature 42.

The geometric design and the choice of the material (conductivity) of the busbar determine the required electrical resistance of the heating conductor for a current range to be provided. As mentioned, the bus bar is made by punching a flat strip. To form the heat conductor resistance, an element is inserted in the punching tool, with which the width and length of the slot 13 S between the two webs 13 is punched. By choosing the material (copper alloy) and by specifying the width and length of the slot, the resistance of the heating element can be formed. It should be briefly mentioned that the heating element can also be formed only from a web 13. It should be clear that the described manufacturing process has advantages, namely with a

Insert element in the punching tool to punch out a slot. The less favorable alternative would be to use different punching tools because of the different web widths and lengths. As mentioned, the resistance of the heat conductor is set according to the rated current range of the switch. For example, four different heat conductor designs are produced for typical applications of a circuit breaker in the rated current range between 125 and 250 A.

The adjustment of the current flow in the triggering device for different current ranges thus takes place in each case such that at a certain derived overcurrent, the bimetallic strip heats up and deforms so that it actuates the tripping bridge (see FIG. 4) with an adjusting screw 24 which is not shown Switching mechanism of the switching device is in operative connection and opens the switch contacts.

The magnetic yoke 51 surrounds the current conductor 10. The rapid release consisting of the U-shaped magnetic yoke 51 and magnet armature 42 also engages with the upper triggering lug 46 on the triggering bridge. The armature 42 is designed as a hinged armature. At a high fault current, such as a short circuit, the armature 42 is folded counter to a tension spring 48 to the yoke 51. The trigger tab 46 of the quick release is on the upper part 41A of the magnetic apparatus (the rotation axis 44 opposite) and arranged at approximately the same height as the set screw 24 of the bimetallic strip 21.

The magnetic yoke 51 consists of a punched-bent part. On the back of the upper part 5OA is the opening for placing on the rivet stub 15 on the busbar. An arm 52 protrudes upward as a bearing for the armature spring 48 designed as a tension spring. Center is right and left a small pin 44 is present, which serves as an axis for the rotatably hinged anchor 42. The also produced as a punch-bend part 41, on which the armature 42 is formed, has a U-shaped upper 41 A and a U-shaped lower formation 41 B. The lower training 41 B represents the actual anchor 42, which comes to lie opposite the yoke 51. For fixing the part 41 on the yoke 51, this part has two holes 44 associated with the pins. For assembly, the upper U-shaped formation 41A is slid toward the pins 44, spreading slightly. To facilitate assembly, the material lugs carrying the holes are slightly angled outwards. The holes snap into the pins 44. This magnet yoke and anchor are positioned to each other. The U-shaped top part has In the armature spring 48 (with little or no energization of the magnet apparatus 40) determined position of the armature to the magnetic yoke yoke and armature have a predetermined air gap, which is substantially from the stop lug 45 (FIG. see Fig. 1A) and of the bending of the armature 42 from the vertical (with respect to installation position, or intended as a parallel to the leg 10A of the busbar) is defined.

By using suitable magnetic material of appropriate thickness, the magnetic properties (eg, flooding or saturation limits) of the magnet apparatus can be specified very accurately without the need for additional parts.

The magnet apparatus thus consists only of three parts (41, 50, 48), which are fastened to the busbar (10B) at a single point (15). It is available as a strong saving of components, which also brings a tolerance improvement, and means a reduced manufacturing, assembly and cost. For the function of the quick release, no further parts or sections in the housing of the switching device are required, such as bearings for the armature spring or bearings for the armature itself.

In Fig. 4 is a diagram showing an assembly of three tripping devices in a switching device. The armature springs 48 between the spring bearings 47 and 52 (see also Fig. 1 A and 3) are omitted in the drawing. The tripping device is operatively connected to a tripping bridge 84, which is also the pawl of the energy accumulator at the same time. For this purpose, the upper part 41A of the anchor part on a flag 46, which abuts the trip bridge 84. The setting of the trigger sensitivity of the quick release is achieved by means of an adjustment knob, not shown, the trigger bridge of the quick release, with an adjusting knob an eccentrically formed pin applies, which shifts the trigger bridge laterally (parallel to its longitudinal direction) upon rotation. Due to the displacement of the tripping bridge, the gap between the bimetallic strip and the tripping bridge (simultaneously on all three tripping devices) is changed by the slope 85 on the tripping bridge. By the shift the air gap between the armature 42 and magnetic yoke 51 is changed, whereby the tripping current and the tripping sensitivity are adjusted.

Through openings in the housing wall, the grub screws 24 of the bimetallic strip are accessible (not shown). These serve as calibration elements for setting the overcurrent to be switched.

The present invention is not limited to the embodiments described above, but also encompasses all embodiments which are equivalent in terms of the invention.

Claims

A device for triggering an electrical switching device, comprising per phase of the electrical current:

an electromagnetic quick release comprising a magnet apparatus (40, 42, 50), wherein the current flowing through the device (100) is used to generate a magnetic field for the quick release,

a thermal overcurrent release (20) comprising a busbar (10) and a sheet-like bimetallic strip (21) closely fitting the busbar (10),

- Wherein the overcurrent release (20) and / or the magnetic apparatus (40) is operatively connected to a trip bridge (84) of the switchgear opening switching mechanism, and a portion (13) of the busbar (10) in the region of the bimetallic strip (21) geometrically formed is that section

(13) has a predetermined resistance value for generating a heating power for heating the bimetallic strip (21), characterized in that the bus bar (10) is formed from a flat piece of material, and further formed on it - a power supply terminal (1 1),

a tab (12) for current transmission to a switching contact of the switch,

at least one attachment point (14) for the bimetallic strip (21),

- An attachment point (15) for the magnetic apparatus (40), and - fixing webs (16) for fixing and mounting of the device (100) in a switch housing.

2. triggering device according to claim 1, characterized in that the busbar (10) is bent in a U-shape, and at right angles projecting from a first U-leg (10 A) of the power supply terminal (1 1) and projecting at right angles from a second U Leg (10 B) the current conductor tab (12) are formed.

3. triggering device according to claim 2, characterized in that the magnet armature (42) and magnetic yoke (51) existing magnetic apparatus (40) in Space between the two U-legs (1 OA, 10B) and the bimetallic strip (21) on the outside of the second U-leg (1 OB) is attached.

4. triggering device according to claim 3, characterized in that the training düng of magnetic yoke (51) and armature (42) is such that they surround the portion (13) and the bimetallic strip (21) applied there.

5. triggering device according to one of the preceding claims, characterized in that the section (13) consists of two parallel strips of material.

6. Tripping device according to one of the preceding claims 2 to 5, characterized in that the fastening webs (16) for fixing and mounting of the device (100) on the first U-legs (10A) are formed.

7. triggering device according to one of the preceding claims, characterized in that the at least one attachment point for the bimetallic strip (21) is designed as a rivet stump (14).

8. Tripping device according to one of the preceding claims, characterized in that the attachment point for the magnet apparatus (40) is designed as a rivet stub (15).

9. tripping device according to one of the preceding claims, characterized in that the current conductor tab (12) is designed as a stranded connection.

10. Tripping device according to one of the preceding claims, characterized in that an operative connection of the device (100) with the switching mechanism of a switching device is produced in that the

Overcurrent release (20) and / or the magnet apparatus (40) is brought into frictional contact by installation in a switch housing with a switching bridge acting on the trigger bridge (84).

1 1. triggering device according to the preceding claim, characterized in that the overcurrent release (20) has an adjusting screw (24) is present, which in frictional contact with the trigger bridge (84) can be brought.

12. triggering device according to one of claims 10 or 11, characterized in that the magnet apparatus (40) has a lug (46) which can be brought into frictional contact with the triggering bridge (84).

13. Triggering device according to one of the preceding claims, characterized in that the parts (41, 50) of the magnetic apparatus (40) each have two offset in height arranged portions (5OA, 5OB, 41 A, 41 B), wherein the arranged below sections (5OB , 41 B) yoke (51) and anchor (42) form and at the above-arranged portions (5OA, 41A) each have a boom (47, 52) for holding a tension spring (48) are formed.