EP3871803A1 - Electromagnetic coil arrangement and electromagnetic roller for a continuous casting plant - Google Patents

Abstract

The present invention relates to the field of metallurgical plants, specifically an electromagnetic coil arrangement for an electromagnetic stirring roller of a continuous casting plant. The object of this invention is to create an electromagnetic coil arrangement and an electromagnetic stirring roller, which on the one hand allows a stable arrangement of the iron core over the casting production width and on the other hand, avoiding additional eddy current losses as far as possible. The object is achieved by an electromagnetic coil arrangement (1) for an electromagnetic stirring roller (30) in a continuous casting plant. This comprises an iron core (2) with a cross section and a first longitudinal extension (L1) and at least two coil winding packages (10). The iron core (2) is arranged in a support tube (3). The support tube (3) consists of a hollow profile, the support tube (3) having at least one slot (4) along a second longitudinal extension. The iron core (2) is designed in such a way that a partial volume of the iron core (2a) can be pushed into the slot (4); the partial volume (2a) preferably fills the slot almost completely.

Description

Field of technology

• eine Rolle mit kreisrundem Hohlquerschnitt welche beidseitig drehbar gelagert ist,
• einen Zufluss für Kühlmittel
• einen Abfluss für Kühlmittel.

The present invention relates to the field of metallurgical plants, specifically an electromagnetic coil arrangement for an electromagnetic stirring roller in a continuous casting plant. The electromagnetic coil arrangement comprises an iron core with a cross section A and a first longitudinal extension and at least two coil winding packages, two fastening stubs with at least two electrical connection contacts, which are each connected to at least one coil winding package. The invention also relates to an electromagnetic stirring roller for a continuous casting plant for the production of products with large cross-sections, in particular slabs. The agitator roller includes:

• a roller with a circular hollow cross-section which is rotatably mounted on both sides,
• an inlet for coolant
• a drain for coolant.

State of the art

Electromagnetic stirrers are used in continuous casting plants for the production of high-quality electrical steels. If the stirrer is in the area of the so-called casting arch, it is referred to as a strand stirrer. If the electromagnetic stirrer is installed in a roll of a segment of the continuous casting plant, it is known as a stirrer roll.

The strand stirrer generates a stirring force in the liquid area of the strand, which moves the liquid steel horizontally along a casting production width and creates a butterfly-like flow pattern in the liquid steel. The structure looks usually a pair of rollers which act on the strand either from both sides or side by side. Such stirring rollers are for example from the documents US2015 / 0290703 A1 and US2013 / 0008624 A1 known.

These stirring rollers consist of an iron core and winding stacks, whereby the inductance should be as high as possible in order to achieve an optimal stirring effect. The iron core therefore consists of a soft magnetic material with the highest possible saturation magnetic flux density and high magnetic permeability. Iron cores made of solid material can hardly be used sensibly, since eddy currents arise in the iron under the influence of variable magnetic fields. This creates additional losses in the iron, which have to be dissipated in the form of heat. In order to avoid this, the iron core for agitator rollers is designed as a laminated and insulated sheet-metal core, which is also referred to as a sheet-metal version. In order to keep the air gap in the magnetic circuit as small as possible, the winding stacks should be arranged as close as possible to the iron core. The iron core of the agitator rollers must cover the casting production width.

The iron core must be supported or stabilized by means of suitable measures so that it has the necessary stability over the casting production range. It must also be ensured that the waste heat generated in the winding stacks is dissipated. When operating such a stirring roller, a plant operator is always concerned to achieve the best possible stirring effect and therefore to apply the highest possible currents to the stirring roller in order to produce a correspondingly strong magnetic field. However, the support structures can lead to additional eddy current losses which lead to additional heat input. This heat input has to be transported away via complex measures, such as cooling channels created in the roll or via the copper winding.

In the US4429731A1 shows an electromagnetic coil arrangement in which an iron core is pushed from the outside to the inside onto a support body and is screwed to it. The winding stacks are arranged in recesses in the iron core and the support body.

Summary of the invention

The object of this invention is to create an electromagnetic coil arrangement and an electromagnetic agitator roller of the type mentioned at the beginning, which on the one hand allows a stable arrangement of the iron core over the casting production width and on the other hand avoids additional eddy current losses as far as possible.

In the case of the electromagnetic coil arrangement mentioned at the outset, the object is achieved in that the iron core is arranged in a hollow support tube. The iron core is designed as a laminated iron core. The iron core is a laminated and insulated laminated core so that eddy current losses are minimized as much as possible. The support tube consists of a hollow profile with an inner wall, an outer wall and a second longitudinal extension. The support tube thus has a hollow cross-section and extends in one direction - that is, has a certain length. The support tube ensures the stability of the iron core along the first longitudinal extension and thus functions as a support structure for the iron core. However, this design inevitably leads to an enlargement of the air gap between the winding stacks and the iron core and also to an additional heat input in the support tube due to eddy current losses. In order to minimize these eddy current losses, the support body has at least one slot with a predetermined slot area along the second longitudinal extension, and the slot extends from the outer wall to the inner wall.

The slot has a slot length along the second longitudinal extension and one at right angles to the longitudinal extension Slot width. The slot width and slot length are understood to be the largest dimension in each case. In a preferred embodiment, the slot has a rectangular shape. The support tube is preferably designed as a tube with a circular ring cross section.

The iron core is designed in such a way that a partial volume of the iron core - from the inner surface of the support tube in the direction of the outer surface of the support tube - can be pushed into the slot. The partial volume of the iron core which is pushed into the slot is therefore preferably designed as a negative to the slot. In a preferred embodiment, the partial volume fills the slot almost completely. The slot and the partial volume of the iron core can of course have different dimensions in order to facilitate assembly and manufacture. The essence of the invention is that the support tube ensures the stability of the iron core over the casting production width and that the partial volume of the iron core is as small as possible from the coil winding stacks.

The at least two coil winding stacks completely enclose the outer wall of the support tube and in partial areas along the second longitudinal extension. By pushing the iron core into the slot in the support tube, the coil winding stacks can be arranged very close to the iron core. The coil winding stacks have a protective layer for protection and insulation. This protective layer completely encloses the coil winding packages. In contrast to US4429731A1 the support body is designed as a hollow profile and the iron core is not pushed in from the outside, but is surrounded by a hollow profile and pushed in from the inner wall in the direction of the outer wall. The protective layer surrounds the coil winding stacks in such a way that at least one outside and both lateral surfaces of the coil winding stacks are surrounded by the protective layer. The fastening stubs are each arranged on the front side of the support tube. The electrical connection contacts are each connected to at least one coil winding package. One The preferred arrangement of the electrical connection contacts is on the end faces of the fastening stub. In this preferred embodiment, the fastening stubs have bushings which enable the electrical connection contacts to be guided to an end face of the fastening stub that can be seen from the outside. The coil winding stacks can then be electrically connected to this end face via the connection contacts.

The function of the fastening stubs is to be able to mount the coil arrangement on a bearing block. On the one hand, this design enables the iron core to be arranged over the casting production width due to the support tube and, on the other hand, minimizing the distance between the coil winding stacks and the iron core leads to an increase in the magnetic flux and thus to an increase in the stirring effect. This increase in the magnetic flux can take place without increasing the current and the space requirement.

An expedient embodiment provides that a protective tube with a hollow cross-section, preferably a circular cross-section, encloses the coil winding stacks. The protective tube extends at least over the two coil winding packages. One possible design of the protective tube is that it consists of several parts and existing joints are sealed - for example with glued metal strips. The existing gaps between the protective tube and the coil winding packages are filled with filling compound. The filling compound means that the greatest possible part of the heat is transferred to the inside of the protective tube. This protective tube is made of a material that conducts heat well, preferably non-magnetic steel, and thus conducts the heat from an inside to an outside of the protective tube.

bevorzugt größer $1\frac{\mathrm{W}}{\mathit{mK}},$

aufweist. Die Füllmasse mit dieser Wärmeleitfähigkeit sorgt für eine besonders gute Abführung der Wärme von den Spulenwicklungspaketen zum Schutzrohr.An advantageous embodiment provides that the filling compound has a greater thermal conductivity $0,1\frac{\mathrm{W.}}{\mathit{mK}},$

preferably larger $1\frac{\mathrm{W.}}{\mathit{mK}},$

having. The filling compound with this thermal conductivity ensures particularly good heat dissipation from the coil winding packages to the protective tube.

A preferred embodiment provides that the support tube has a plurality of slots along the second longitudinal extension, in particular at least two, preferably at least four, particularly preferably at least six, very particularly preferably eight slots, each with a predetermined slot area. The iron core is designed in such a way that in each case a partial volume of the iron core can be pushed into one of these slots, the respective partial volumes preferably completely fill the respective slots. The design with several slots has the advantage that the pipe is prevented from expanding due to possible internal mechanical stresses in the pipe by means of webs located between the slots. This embodiment therefore provides that there are between three and ten slots which are arranged along the second longitudinal extension. These webs thus prevent widening - that is, a change in an original - for example circular shape - of the support tube, which can occur after the slot has been produced. In this embodiment, the iron core has a partial volume for each slot, which can be pushed into the slots. Thus, of course, the webs in the iron core must also be shown as negatives so that the partial volumes can be pushed into the respective slots.

Another preferred embodiment provides that cooling channels are arranged next to the iron core within the support tube. These cooling channels run close to the iron core in order to dissipate the resulting heat as effectively as possible. The cooling channels can be designed as a tube which is pushed into the support tube next to the iron core.

It is also conceivable that the iron core has at least one cooling channel. By arranging at least one In the cooling channel, the heat that arises in the iron core can be dissipated particularly effectively.

A further advantageous embodiment of the invention provides that the coil winding stacks are designed in such a way that they can be pushed on for assembly from an end face of the support tube up to an intended assembly position. When pushed on, the coil winding stacks have internal dimensions which are larger than the external dimensions of the support tube in order to allow the coil winding stacks to be pushed onto the support tube. This design is intended to enable the coil winding stacks to be produced without a support tube and the coil winding package and support tube to be assembled separately - that is, the coils are not wound directly onto the support tube. The coil winding stacks can be enlarged in their dimensions during assembly by widening, such as heating or turning the windings, in order to facilitate or enable them to be pushed on. The coil winding stacks are thus designed in such a way that they are in a shape for assembly or can be brought into a shape in order to enable them to be pushed onto the support tube.

Another advantageous embodiment provides that the slot surface is rectangular. This design is preferred in order to achieve the largest possible slot area.

An expedient embodiment provides that the coil winding stacks consist of a maximum of two layers lying one above the other, preferably only one layer, and a large number of turns lying next to one another. The respective coil winding package therefore consists of a large number of turns that are wound next to one another and of a maximum of two layers on top of one another. The number of turns is determined by calculations and depends on a maximum available voltage and a maximum current density at a certain stirring frequency. The goal is always one Provide the highest possible stirring effect, that is, the highest possible magnetic flux density. The individual turns are covered with an insulating material so that the individual turns are electrically isolated from one another. The insulating material is preferably a polyimide film. By designing the coil winding stacks with a maximum of two layers, the heat can be dissipated more easily to the outside or to the protective tube - which can be easily cooled from the outside. It has also been shown that by minimizing the layers - to a maximum of two - the electromagnetic flux density can be kept at a higher level for a longer period of time than is the case with an embodiment with more than two layers, since the heat generated can be better discharged. This design reduces a temperature difference between the inner layer and the outer layer to up to 120 Kelvin. In the preferred embodiment of the coil winding packs with only one layer - with a current density of 17 A / m ² - the temperature difference between inside and outside can be reduced to up to 60 Kelvin. In the case of designs with several layers, temperature differences - between the inner and outer layers - of 200 Kelvin were determined, which means that there is a risk of the maximum temperature of the insulating materials being exceeded. In order to prevent this, the energy fed into the coils, i.e. the current, must be reduced in such a case. As a result, the stirring effect is reduced.

A particularly preferred embodiment is that the turns have a rectangular cross section, the dimensions of the turn being larger in the radial direction than in the axial direction. The ratio of the dimension in the axial direction - i.e. a width of a cross section of the turn - to the dimension in the radial direction - i.e. a height of a cross section of the turn - is preferably in a range from 1/3 to 1/8, particularly preferably 1/4 to 1/6. The turns are therefore designed as so-called standing turns. The rectangular cross-section allows Arrange several narrow and high turns next to one another in order to obtain the desired number of turns and still produce a compact coil winding package. In this context, rectangular is also understood to mean that the corners can have rounded portions which ensure simpler assembly when assembling the coil winding arrangement.

A winding with a rectangular cross section and only one layer has emerged as a particularly preferred embodiment. This embodiment variant results in particularly good heat dissipation to the outside. Tests have shown that this results in the lowest temperature difference. With this single-layer design, there are no transitions in the radial direction from an insulated turn to an overlying insulated turn, which results in particularly good heat transport to the outside.

In a further expedient embodiment, the electrical connection contacts have a bolt with a bolt cross-sectional area, which can transmit the required energy to the coil winding stacks, and a fastening bolt stub with a fastening cross-sectional area. The bolt cross-sectional area and the fastening cross-sectional area have a ratio of 1.7 to 4. For these applications, it must be possible to arrange and fasten the connection contacts in a very limited space. For this reason, the connection contact should, on the one hand, be able to transmit the required energy to the coil winding stacks and, on the other hand, have a reliable fastening. The connection of electrical supply cables to the connection contacts should preferably take place via a cable lug. The cable lug is pushed onto the fastening stub, which must be fixed in such a way that it has good contact with the cross-sectional area of the bolt. This is preferably done in that the fastening bolt has a thread and a Screwing on a nut, the cable lug is pressed against the fastening cross-sectional area. The contacts require less space due to the reduced mounting cross-sectional area. This design makes it possible that the connection contacts - despite the limited space requirement - can be arranged on the end faces of the fastening stubs.

$$R_{m,l}=\frac{{\mathrm{l}}_{\mathit{Luft}}}{{\mu }_0\ast A}$$

$$R_{m,\mathit{Fe}}=\frac{{\mathrm{l}}_{\mathit{Fe}}}{{\mu }_0\ast {\mu }_r\ast A}$$

$$R_{m,\mathit{ges}}=R_{m,l}+R_{m,\mathit{Fe}}$$

A particularly preferred embodiment provides that the coil winding stacks closest to the fastening stubs and all coil winding stacks electrically connected to them have a higher total number of turns than a total number of turns of all other coil winding stacks - each electrically connected to one another. The coil winding stacks that are placed on the edge have a larger air gap, since magnetic field lines emerge at least partially over one of the two end faces of the iron core. As a result, these coil winding stacks have a greater length of the air gap l _air in the magnetic circuit compared to those coil winding stacks which are not placed at the edge. This means that a total magnetic resistance R _{m, tot} (cf. equation 4) is higher and the inductance therefore decreases. The inductance L is calculated using equation 1, where N is the number of turns. The magnetic resistance in the air gap is calculated according to equation 2, where µ _{0 is} the permeability of vacuum and A is the cross-sectional area of the magnetic conductor. Equation 3 shows the formula for the magnetic resistance in iron, where µ _{r is} the relative permeability of the iron core. $$\mathrm{L.}=\frac{{\mathrm{<figure-callout\; id="2"\; label="N"\; filenames="imgf0002.png,imgf0004.png"\; state="\{\{state\}\}">N</figure-callout>}}^2}{{\mathrm{R.}}_{m,\mathit{total}}}$$

$${\mathrm{R.}}_{m,l}=\frac{{\mathrm{l}}_{\mathit{air}}}{{\mu }_0\ast \mathrm{A.}}$$

$${\mathrm{R.}}_{m,\mathit{Fe}}=\frac{{\mathrm{l}}_{\mathit{Fe}}}{{\mu }_0\ast {\mu }_r\ast \mathrm{A.}}$$

$${\mathrm{R.}}_{m,\mathit{total}}={\mathrm{R.}}_{m,l}+{\mathrm{R.}}_{m,\mathit{Fe}}$$

These equations are used to understand the relationships, but an analytical calculation of the magnetic resistance is difficult due to the largely unknown air gap and the dynamic changes during operation of a stirring roller, and is accordingly also solved using finite element methods (FEM) programs.

The embodiment according to the invention provides that all coil winding packages connected to one electrical contact each have almost the same inductivity. As can be seen in equation 1, the inductance can be changed either via the number of turns N or via the magnetic resistance R _{m, ges} . The simplest version results from adapting the number of turns. The coil winding stacks connected to the individual electrical connection contacts should have almost the same current-carrying capacity and inductivity due to the adaptation of the total number of turns. With this solution, it is possible to increase the electrical power of the agitator roller in the size range of 5% with the same space conditions. This takes place through an ideal - that is, the same - current distribution to all coil winding stacks of the electromagnetic coil winding arrangement.

A preferred embodiment provides that the electrical coil winding arrangement has three electrical connection contacts and the number of coil winding stacks corresponds to a multiple of three plus two. The number of coil winding packages is for example at least five, preferably at least eight, particularly preferably at least eleven, very particularly preferably fourteen. The coil winding stacks closest to the fastening stubs have a smaller number of turns than the remaining coil winding stacks. In this embodiment, the coil winding stacks which are arranged in the vicinity of the fastening stub, that is to say are arranged on the edge of the iron core, serve as so-called compensating coil winding stacks. One embodiment provides that a connection contact is connected to the two coil winding packages closest to the fastening stub. In this embodiment, the number of turns of the compensating coil winding stacks is greater than half the number of turns but smaller than the number of turns of the remaining coil winding stacks. Another embodiment is that in each case two electrical connection contacts are connected to a compensating coil winding package.

An advantageous embodiment provides that the electromagnetic coil winding arrangement has three electrical connection contacts. The number of coil winding packages is at least three or a multiple of three. The coil winding stacks closest to the fastening stubs have a greater number of turns than the remaining coil winding stacks. In this embodiment, at least two electrical connection contacts are connected to a coil winding package closest to the fastening stubs.

The object according to the invention is achieved by the electromagnetic agitator roller mentioned at the beginning. The electromagnetic coil arrangement described above is arranged within the reel. The electromagnetic coil arrangement is fixed to a bearing block on both sides. A cooling channel, which is connected to the inflow and the outflow, is formed between the tube and the coil arrangement. The role has a supporting effect on the strand. This arrangement results in an electromagnetic agitator roller, which with the same electrical connection power and Size a larger magnetic flux and thus an increased stirring effect achieved.

In a particularly preferred embodiment, the roller is rotatably mounted on both sides of the bearing block. This design has proven to be a particularly robust design. Another embodiment is that the storage takes place on the fastening stubs.

Brief description of the drawings

• Fig. 1 a schematic representation of a coil winding arrangement according to the invention
• Fig. 2 a schematic representation of a variant embodiment of a coil winding arrangement
• Fig. 3 a schematic cross section of an embodiment variant of a coil winding arrangement
• Fig. 4 a schematic cross section of a further embodiment of a coil winding arrangement
• Fig. 5 a schematic representation of a stirring roller
• Fig. 6-7 a schematic representation of an embodiment of a coil winding arrangement
• Figures 8-9 a further schematic illustration of an arrangement of coil winding stacks in a coil winding arrangement
• Fig. 10-13 schematic representations of embodiments of the electrical connection contacts
• Fig. 14 a schematic representation of a support tube
• Fig. 15 schematic representation of a coil winding package

Description of the embodiments

In the Fig. 1 a coil winding arrangement 1 according to the invention is shown. In the Fig. 1 shows how an iron core 2 is placed in a support tube 3. The iron core 2 has a first longitudinal extension L1 - that is to say a certain length - and the support tube 3 has a second longitudinal extension L2 - that is also a certain length. The support tube 3 has a slot 4 into which a partial volume of the iron core 2a is pushed. The slot 4 extends from the inner wall 3a to an outer wall 3b of the support tube. A residual volume of the iron core 2b is located inside the support tube 3. The support tube 3 and the iron core 2 are enclosed by coil winding stacks 11. In this embodiment there are two coil winding stacks 11, each of which is electrically connected to electrical contacts 15 which are located on the fastening stubs 12. This electrical connection exists on both sides, that is to say on the left fastening stub 12 and on the right fastening stub 12. Different phases of a supply network are connected to the electrical contacts 15 on one side during operation. The at least two electrical contacts 15 have no mutual electrical connection. The coil winding stacks 10 are surrounded by a protective layer 13a. The coil winding stacks 10 are designed in such a way that they can be pushed on for assembly from an end face 6a up to an assembly position 6b.

In Fig. 2 a coil winding arrangement 1 is shown, which extends from Fig. 1 differs in that the support tube 3 has several slots 4. A web 5 is provided between the slots. These webs 5 have the function of preventing the support tube 3 from expanding when the slot is created. Like in the Fig. 2 As can be seen, the webs are arranged in such a way that, in a preferred embodiment, they are completely enclosed by a coil winding set - that is, the webs 5 are located under a coil winding set 10.

The iron core is - in this embodiment variant with several slots - designed so that it also has a number of partial volumes of the iron core 2a corresponding to the number of slots, which almost completely fill the respective slots. The partial volumes of the iron core 2a are shown by the vertical hatching. The coil winding stacks 10 are surrounded by a protective tube 13. Gaps present between the coil winding stacks 10 and the protective tube 13 are filled with a filling compound 14.

The cross section of a coil winding arrangement is shown in FIG Fig. 3 shown. The iron core 2 - which has a cross section A - is arranged in the support tube 3. The partial volume of the iron core 2 a is pushed into the slot 4 of the support tube 3. In this embodiment, the partial volume of the iron core 2a almost fills the slot, but there is a small gap on the left and right to enable insertion. The coil winding stacks 3 enclose the iron core 2 and the support tube 3, the coil winding stacks 10 having two layers 11a. The coil winding stacks 10 are enclosed by the protective tube 13, a remaining space being filled with filling compound 14. Cooling channels 20 are arranged next to the iron core.

In Fig. 4 In addition to the cooling channels 20, there is a cooling channel in the iron core 21. The arrangement of the cooling channels shown here is only an example; it is also conceivable that only the cooling channels 20 or only the cooling channels are present in the iron core 21.

the Fig. 5 shows a stirring roller 30 for a continuous casting plant. The agitator roller 30 comprises the coil winding arrangement 1 and a roller 31 which supports a strand produced by the continuous casting plant. The coil winding arrangement 1 is fixed on both sides in a bearing block 36 - via the fastening stub 12. The roller 31 is rotatably mounted on both sides. In this embodiment, the bearing 35 arranged in the bearing block 36. A cooling channel 34 is formed in the space between the coil winding arrangement 1 and the roller 31. A coolant can be supplied by an inflow of coolant 32 and removed again through an outflow of coolant 33. The electrical contacts 15 are each connected to a coil winding package 10.

In Fig. 6 a preferred embodiment of the coil winding stacks 10 is shown. The coil winding stacks consist of a layer 11a and a plurality of turns 11b. The single-layer design ensures particularly good dissipation of the heat to the outside to the protective tube 13 or the insulating layer 13a (not shown).

In Fig. 7 an alternative embodiment of the coil winding stacks 10 is shown. The coil winding stacks 10 have two layers 11a and each layer 11a has a plurality of turns 11b.

In Fig. 8 A schematic representation of one embodiment of the coil winding assembly is shown. The iron core 2 with a cross section and a first longitudinal extension is enclosed along the first longitudinal extension by a plurality of coil winding stacks 10u, 10v, 10w. The coil winding packs of phase u 10u has a greater number of turns 11b than the coil winding pack of phase v 10v and the coil winding pack of phase w 10w. As from the Fig. 8 As can be seen, two coil winding packages are connected to each of the three phases. Phase u and phase w are each connected to a coil winding package 10u, 10w which is closest to the fastening stub. These coil winding stacks 10u, 10w connected to phases u and phase w have a higher number of turns than the coil winding stacks 10v connected to phase v. The associated with the individual phases u, v, w Coil winding packages 10u, 10v, 10w should have a number of turns that have almost the same current carrying capacity and almost the same inductance. For this embodiment, the number of coil winding packages is a multiple of three - for example three, six, nine, twelve, etc.

In Fig. 9 Figure 3 is another schematic representation of a preferred embodiment. In this arrangement, only phase u has an electrical connection to coil winding stacks 10u which are closest to the end faces of iron core 2 or the fastening stub (not shown). The coil winding stacks 10u connected to the phase u have a higher number of turns than the coil winding stacks 10v, 10w connected to the phase v and the phase w.

In Fig. 10 Advantageous embodiments of the connection contacts 15 are shown as a plan view. The space required on the fastening stub 12 for connecting three phases is small. On the one hand, it must be ensured that the required current can be conducted via the electrical connection contacts 15 and, on the other hand, secure attachment can take place. An electrical connection cable is fastened in a cable lug 43 and pressed tightly against the electrical connection contact 15 with a fastening element 42 - in the present example a nut.

In Fig. 11 is a floor plan and elevation of the in Fig. 10 described connection contacts shown schematically. The cable lug 43 is pressed firmly onto the bolt cross-section 40a by means of a fastening element (nut) 42 and a washer 44. The fastening bolt 41 has a fastening bolt cross section 41a. The ratio of bolt cross-section 40a and fastening bolt cross-section 41a is in a preferred embodiment in the ratio of 1.7 to 4. The bolt 40 is advantageously designed with a round cross section and the fastening bolt 41 has a thread. In the embodiment of the bolt 40 with a round cross-section, a bolt diameter is in the range from 14 mm to 20 mm in order to be able to transmit the currents required for the coil winding stacks. A ratio of bolt diameter to fastening bolt thread diameter - the nominal thread diameter being used here - is between 1.3 and 2.

In the Fig. 12 is an enlarged view of an electrical connection contact, with the bolt 40, the cable lug 43, the washer 44 and the fastening element 42 which is screwed onto the fastening bolt 41, is shown.

In Fig. 13 a further preferred embodiment is shown, which differs from that in Fig. 12 differs in that a washer 44 is attached on both sides of the cable lug 43. The washer 44 which rests on the bolt 40 can also be rigidly connected to the bolt - for example by being welded to the bolt 40. But it is also conceivable that instead of the washer - which rests on the bolt - a nut is screwed onto the bolt or the fastening bolt.

In Fig. 14 a support tube 3 is shown with a plurality of slots 4, each with a slot surface. The webs 5 are located between the slots 4. The partial volumes of the iron core can be pushed into the slots 4.

In Fig. 15 a coil winding package 10 is shown with one layer. Typical dimensions of the turns of the coil winding package 10 are a width of 3 mm and a height of 12 mm.

Although the invention has been illustrated and described in more detail by the preferred exemplary embodiments, the invention is not restricted by the disclosed examples and other variations can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention according to the claims.

List of reference symbols

1

Coil winding arrangement

2

Iron core

2a

Partial volume of the iron core

2 B

Residual volume of the iron core

3

Support tube

3a

Inner wall

3b

Outer wall

4th

slot

5

Bridges

6a

Front side

6b

Coil winding package

10

Phase u coil winding packages

10u

Coil winding packages of phase v

10v

Phase w coil winding packages

10w

location

11a

Turns

11b

Fastening stub

12th

Protective layer

13a

Protection tube

13th

Filling compound

14th

Electrical connection contacts

15th

Cooling duct

20th

Cooling channel in the iron core

21

Agitator roller

30th

role

31

Inflow for coolant

32

Drain for coolant

33

Cooling duct

34

camp

35

Bearing block

36

bolt

40

Bolt cross-section

40a

Fastening bolt stub

41

Fastening bolt stub cross-section

41a

Fastener

42

Cable lug

43

Washer

44

Phase u

u

Phase v

v

Phase w

w

First longitudinal extension

L1

Second longitudinal extension

L2

cross-section

A.

Claims (15)

Electromagnetic coil arrangement (1) for an electromagnetic stirring roller (30) of a continuous casting plant comprising an iron core (2) with a cross section (A) and a first longitudinal extension (L1) and at least two coil winding packages (10), two fastening stubs (12), at least two electrical ones Connection contacts (15) which are each connected to at least one coil winding set (10), characterized in that - the iron core (2) is arranged in a support tube (3), - wherein the support tube (3) consists of a hollow profile with an inner wall and an outer wall and a second longitudinal extension (L2), - wherein the support tube (3) along the second longitudinal extension has at least one slot (4) with a predetermined slot area and the slot (4) extends from the outer wall (3b) to the inner wall (3a), - The iron core (2) being designed in such a way that a partial volume of the iron core (2a) can be pushed into the slot (4) from the inner wall (3a) of the support tube in the direction of the outer wall (3b) of the support tube (3), preferably the partial volume (2a) fills the slot almost completely, - wherein the at least two coil winding stacks (10) enclose the outer wall (3b) of the support tube (3) in partial areas along the second longitudinal extension L2, - wherein a protective layer (13a) encloses the coil winding stacks (10), - The fastening stubs (12) are each arranged on the end face of the support tube (3). Electromagnetic coil arrangement (1) according to Claim 1, characterized in that the protective layer (13a) is a protective tube (13) with a hollow cross-section, preferably with a circular cross-section, the protective tube (13) enclosing the coil winding stacks (10) and existing gaps between the protective tube (13) and the coil winding stacks (10) being filled with filling compound (14). Electromagnetic coil arrangement according to Claim 2, characterized in that the filling compound (14) has a greater thermal conductivity $0,1\frac{\mathrm{W.}}{\mathit{mK}},$

preferably larger $1\frac{\mathrm{W.}}{\mathit{mK}},$

having. Electromagnetic coil arrangement according to one of the preceding claims, characterized in that the support tube (3) along the second longitudinal extension (L2) has a plurality of slots (4), in particular at least two, preferably at least four, particularly preferably at least six, very particularly preferably eight slots ( 4), each with a predetermined slot area and the iron core (2) is designed in such a way that a partial volume of the iron core (2a) can be pushed into these slots (4), preferably the respective partial volumes of the iron core (2a) fill the slots (4) completely off. Electromagnetic coil arrangement according to one of the preceding claims, characterized in that cooling channels (20) are arranged next to the iron core (2) within the support tube (3). Electromagnetic coil arrangement according to one of the preceding claims, characterized in that the coil winding stacks (10) are designed in such a way that they can be pushed on for assembly from an end face of the support tube (3) up to an intended assembly position. Electromagnetic coil arrangement according to Claims 1-6, characterized in that the slot surface is rectangular. Electromagnetic coil arrangement according to Claims 1 - 7, characterized in that the coil winding stacks (10) consist of a maximum of two superimposed layers (11a), preferably only one layer (11a), as well as a large number of adjacent turns (11b) and the individual turns ( 11b) are coated with an insulating material. Electromagnetic coil arrangement according to Claim 8, characterized in that the turns (11b) have a rectangular cross section, the dimensions of the turn (11b) being larger in the radial direction than in the axial direction; a ratio of the dimension in the axial direction to the dimension in the radial direction is preferred a range from 1/3 to 1/8, particularly preferably in a range from 1/4 to 1/6. Electromagnetic coil arrangement according to Claims 1 - 9, characterized in that the electrical connection contacts (15) have a bolt (40) with a bolt cross-sectional area (40a), which can transmit the required energy to the winding stacks, and a fastening bolt stub (41) with a fastening cross-sectional area (41a), wherein the bolt cross-sectional area (40a) and the fastening cross-sectional area (41a) have a ratio of 1.7 to 4. Electromagnetic coil arrangement according to Claims 1-10, characterized in that the coil winding stacks (10) closest to the fastening stubs (12) and all coil winding stacks (10) electrically connected to them have one have a higher total number of turns than a total number of turns of all other coil winding stacks (10) that are electrically connected to one another. Electromagnetic coil arrangement according to Claims 1-11, characterized in that it has three electrical connection contacts (15) and has a number of coil winding packages (10), the number corresponding to a multiple of three plus two and the coil winding packages (12) closest to the fastening stub (12) in each case. 10), have a smaller number of turns than the remaining coil winding packages (10). Electromagnetic coil arrangement according to Claims 1-12, characterized in that it has three electrical connection contacts (15) and has coil winding packages (10) with a number of at least three or a multiple of three, the coil winding packages (10) closest to the fastening stubs (41) in each case. have a larger number of turns than the remaining coil winding packages (10). Electromagnetic agitator roller for a continuous casting plant for the production of products with large cross-sections, in particular slabs, comprising: - a roller (31) with a circular hollow cross-section which is rotatably mounted on both sides, - an inlet for coolant (32), - a drain for coolant (33), characterized in that the electromagnetic coil arrangement (1) according to claims 1-13 is arranged inside the roller (31) and this is fixed on both sides on a bearing block (36), with a cooling channel (20) between the tube (31) and the coil arrangement (1) ) is formed, which is connected to the inflow (31) and the outflow (32). Electromagnetic agitator roller according to claim 14, characterized in that the roller (31) is rotatably mounted on the bearing block on both sides.

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