EP3766600B1 - Electromagnetic coil arrangement for an electromagnetic stirrer roller of a continuous casting plant - Google Patents

Description

field of technology

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

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 electromagnetic coil arrangement comprises an iron core with a cross section and a first longitudinal extent 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. Furthermore, the invention relates to an electromagnetic agitator roller for a continuous casting plant for the production of products with large cross sections, in particular slabs. The stirring roller includes:

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

State of the art

Electromagnetic stirrers are used in continuous casting plants to produce high-quality electrical steel. If the stirrer is located in the area of the so-called pouring arch, it is referred to as a strand stirrer. If the electromagnetic stirrer is installed in a roller of a segment of the continuous casting plant, it is referred to as a so-called stirrer roller.

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

In the documents US 4,429,731A , EP 2269750 A1 , SU1616770 A1 and US3,995,678A Variants of agitator rollers for use in continuous casting plants are shown.

These stirring rollers consist of an iron core and coil winding packs. These coil winding packets consist of a wire that is wound into a large number of windings lying next to one another and layers lying one on top of the other. The wire is covered with an electrical insulation layer. The current-carrying winding packages enclosing the iron core generate the magnetic flux, which depends on the number of turns and the current strength in the windings. The magnitude of the magnetic flux density in turn determines the strength of the stirring force of the electromagnetic stirrer. The ohmic resistance of the windings results in a certain power loss, which is converted into heat and must be dissipated by cooling. The electrical insulation layer is a poor conductor of heat, which means that the heat from the lower layers of the winding packages is poorly transported to the outside, where the heat can be dissipated particularly effectively. There is therefore the problem for a bottom layer of the winding that the maximum temperature of the insulation layer is reached after a certain time and the current intensity must therefore be limited. As a result, the stirring power is also limited accordingly.

Summary of the Invention

The object of this invention is an electromagnetic coil assembly and a to create electromagnetic stirring roller of the type mentioned, which an effective heat dissipation - the heat generated in the coil winding packets - enables the to be able to operate the electromagnetic coil arrangement and the electromagnetic stirring roller with the highest possible performance.

The object is achieved with the electromagnetic coil arrangement mentioned at the outset in that the at least two coil winding packets enclose the iron core in partial areas along the first longitudinal extension. The first longitudinal extension means an iron core length. The coil winding packages consist of a maximum of two layers lying one on top of the other, preferably only one layer, and a large number of turns lying next to one another. The respective coil winding packet thus consists of a large number of windings that are wound next to one another and of a maximum of two layers lying one on top of the other. The number of turns is determined by calculations and depends on a maximum available voltage and a maximum current density at a given stirring frequency. The goal is always to provide the highest possible stirring effect, i.e. the highest possible magnetic flux density. The individual windings are covered with an insulating material so that the individual windings are electrically insulated from one another. The insulating material is preferably a polyimide film. The coil winding packets are designed in such a way that they can be slid onto the iron core from one end face of the iron core up to an intended assembly position for assembly. When pushed on, the coil winding packets have internal dimensions which are larger than the external dimensions of the iron core in order to allow the coil winding packets to be pushed onto the iron core. This embodiment is intended to enable the coil winding packages to be produced without an iron core and for the coil winding package and iron core to be assembled separately. The dimensions of the coil winding packets can be increased during assembly by expansion, such as heating or twisting the windings, in order to facilitate or enable sliding. The coil winding packages are ie designed in such a way that they are in a form for assembly or can be brought into a form in order to enable them to be slid onto the support tube. The coil winding packages have a protective layer for protection and insulation. This protective layer completely encloses the coil winding packages. The protective layer surrounds the coil winding packages in such a way that at least one outside and both lateral surfaces of the respective coil winding package are surrounded by the protective layer. The fastening stubs are arranged on the face of the iron core.

The electrical connection contacts are each connected to at least one coil winding package. A preferred arrangement of the electrical connection contacts is on the end faces of the fastening stubs. In a preferred embodiment, the fastening stubs have bushings which make it possible to guide the electrical connection contacts to an end face of the fastening stub that can be seen from the outside. The coil winding packages can then be electrically connected via the connection contacts to this end face.

The fastening stubs have the function of being able to mount the coil arrangement on a bearing block. The design of the coil winding packages with a maximum of two layers allows the heat to be dissipated more easily. 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 over a longer period of time than is the case with an embodiment with more than two layers. The resulting heat can be dissipated better. This design reduces the temperature difference between the inner layer and the outermost layer to as little as 120 Kelvin. In the preferred embodiment of the coil winding packages with only one layer, the temperature difference between inside and outside can be reduced to up to 60 Kelvin at a current density of 17 A/m ² . In designs with several layers, temperature differences - between the inner and outer layer - of 200 Kelvin, which means there is a risk of exceeding the maximum temperature of the insulating materials. 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 windings have a rectangular cross-section, the dimension of the winding 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 winding - to the dimension in the radial direction - i.e. a height of a cross section of the winding - is preferably in a range from 1/3 to 1/8, particularly preferably 1/4 to 1/6 The windings are therefore designed as so-called standing windings. Due to the rectangular cross section, several narrow and high windings can be arranged next to each other in order to obtain the desired number of windings and still produce a compact coil winding package. In this context, rectangular is also understood to mean that the corners can have curves, which ensure simpler assembly when assembling the coil winding arrangement.

A winding with a rectangular cross section and only one layer has turned out to be a particularly preferred embodiment. This embodiment variant results in particularly good heat dissipation to the outside. Experiments have shown that this results in the lowest temperature difference. In this single-layer design, there are no transitions in the radial direction from the insulated winding to the insulated winding lying above it, which results in particularly good heat transport to the outside.

A further advantageous embodiment of the invention provides that the iron core has at least one cooling channel. By arranging at least one cooling channel, the Heat generated in the iron core can be dissipated particularly effectively.

An expedient embodiment provides that a protective tube with a hollow cross section, preferably a circular cross section, encloses the coil winding packages. The protective tube extends at least over the two coil winding packs. A 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 gaps between the protective tube and the coil winding packages are filled with filling compound. The filling compound means that as much heat as possible is transferred to an inside of the protective tube. This protective tube is made of a material with good thermal conductivity, preferably non-magnetic steel, and thus conducts the heat from an inside to an outside of the protective tube.

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

, 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 thermal conductivity of greater $0.1\frac{\mathrm{W}}{mK}$

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

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

An expedient embodiment provides that the iron core is arranged in a hollow support tube with a second longitudinal extent. The support tube therefore has a hollow cross section and extends along a longitudinal axis. The support tube has a support tube length which is of the order of magnitude of the casting production width. The iron core can be stabilized over the casting production width by the support tube.

A preferred embodiment provides that the support tube has a plurality of slots along the second longitudinal extent, in particular at least two, preferably at least four, particularly preferably at least six, very particularly preferably eight slots, each having 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 fill the respective slots completely. The design with several slits has the advantage that an expansion of the tube due to possible internal mechanical stresses in the tube is prevented by means of webs located between the slits. This embodiment therefore provides for between three and ten slots to be present, which are arranged along the second longitudinal extension. These webs thus prevent a widening--that is, a change in an original--for example annular--shape--of the support tube, which can occur after the slot has been made. In this embodiment, the iron core therefore has a partial volume for each slot, which can be pushed into the slots. Thus, of course, the bars in the iron core must also be shown as a negative, so that the partial volumes can be pushed into the respective slots.

A further 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 heat generated as effectively as possible. The cooling channels can be designed as a tube that is pushed into the support tube next to the iron core.

A further advantageous embodiment provides that the slot area is rectangular. This embodiment is preferred because it achieves the largest possible slot area.

In a further expedient form, the electrical connection contacts have a bolt with a bolt cross-sectional area which can transmit a required energy to the coil winding packets, and a

Fastening bolt stub, with a fastening cross-sectional area. The bolt cross-sectional area and the fastener cross-sectional area have a ratio of 1.7 to 4. For these applications, the connection contacts must be able to be arranged and fastened 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 packets and, on the other hand, have a reliable attachment. Electrical supply cables should preferably be connected to the connection contacts using a cable lug. The cable lug is pushed onto the fastening stub, whereby this 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 the cable lug is pressed onto the fastening cross-sectional area by screwing on a nut. Due to the reduced mounting cross-sectional area, the contacts require less space. This design makes it possible for the connection contacts to be arranged on the end faces of the fastening stubs, despite the limited space required.

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

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

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

A particularly preferred embodiment provides that the coil winding packets closest to the fastening stubs and all coil winding packets electrically connected thereto have a higher total number of turns than a total number of turns of all other coil winding packets—each electrically connected to one another. The coil winding packs, which are placed at the edge, have a larger air gap, since magnetic field lines emerge at least partially via one of the two end faces of the iron core. This means that these coil winding packages have a greater length of the air gap l _air in the magnetic circuit than those coil winding packages that are not placed at the edge exhibit. From this it follows that a total magnetic resistance R _m,ges (cf. equation 4) is higher and the inductance therefore decreases. The inductance L is calculated by Equation 1, where N is the number of turns. The magnetic resistance in the air gap is calculated using 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 reluctance in iron, where µ _r is the relative permeability of the iron core. $$L=\frac{{\mathrm{N}}^2}{R_{m,\mathit{total}}}$$

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

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

$$R_{m,\mathit{total}}=R_{m,l}+R_{m,\mathit{feet}}$$

These equations serve 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 of the coil winding packages connected to an electrical contact each have almost the same inductance. 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 is obtained by adapting the number of turns. The coil winding packets connected to the individual electrical connection contacts should have almost the same current carrying capacity and inductance by adapting the total number of turns. With this solution it is possible to increase the electrical output of the agitator roller in the range of 5% with the same space conditions. This is done by an ideal - ie the same - current distribution to all coil winding packets 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 packages corresponds to a multiple of three plus two. The number of coil winding packets is therefore, for example, at least five, preferably at least eight, particularly preferably at least eleven, very particularly preferably fourteen. The coil winding packages closest to the fastening stubs have a smaller number of turns than the remaining coil winding packages. In this embodiment, the coil winding packets, which are arranged in the vicinity of the attachment stub, that is to say are arranged on the edge of the iron core, serve as so-called compensating coil winding packets. 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 packs is greater than half the number of turns but less than the number of turns of the remaining coil winding packs. Another embodiment is that two electrical connection contacts are connected to a compensating coil winding packet.

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 one multiple of three. The coil winding packages closest to the fastening stubs have a larger number of turns than the remaining coil winding packages. In this embodiment, at least two electrical terminals are connected to a coil winding package closest to the mounting stubs.

The object according to the invention is achieved by the electromagnetic stirring roller mentioned at the outset. The electromagnetic coil assembly described above is located within the roller. The electromagnetic coil arrangement is fixed to a bearing block on both sides. A cooling channel is formed between the tube and the coil arrangement, which is connected to the inflow and the outflow. The role exerts a supporting effect on the strand. This arrangement results in an electromagnetic stirring roller which, with the same electrical connected load and size, achieves a greater magnetic flux and thus an increased stirring effect.

In a particularly preferred embodiment, the roller is rotatably mounted on the bearing block on both sides. 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

• 1 a schematic representation of a coil winding arrangement according to the invention
• Figures 2 - 3 a schematic representation of an embodiment variant of a coil winding arrangement
• 4 a schematic cross section of an embodiment variant of a coil winding arrangement
• figure 5 a schematic cross section of a further embodiment variant of a coil winding arrangement 6 a schematic representation of a stirring roller
• 7 a schematic representation of an embodiment of coil winding packages
• 8 a schematic representation of a further embodiment of coil winding packages
• Figures 9-10 a schematic representation of an arrangement of coil winding packages in a coil winding arrangement
• Figures 11 - 14 schematic representations of embodiments of the electrical connection contacts
• 15 a schematic representation of a support tube
• 16 schematic representation of a coil winding package

Description of the embodiments

In 1 an embodiment of the coil winding arrangement 1 according to the invention is shown. The iron core 2 has a first longitudinal extension L1. This first longitudinal extension L1 results from an extension from a left to a right fastening stub 12. The first longitudinal extension L1 is therefore to be understood as a length of the iron core. The coil winding packages 10 have two layers 11a and a multiplicity of turns 11b. The individual turns 11b are covered with an insulating material. Fastening stubs 12 are arranged on each end face of the iron core. The electrical contacts 15 are also located on the fastening stubs 12. The coil winding packages 10 are connected to an electrical energy supply by means of these electrical contacts 15. The coil winding packets 10 are enclosed in a protective layer 13a so that they are protected against mechanical wear and electrically isolated from the outside. The coil winding packets 10 are designed in such a way that, for assembly, they can be pushed on from an end face 6a to an assembly position 6b.

In the 2 a coil winding arrangement 1 according to the invention is shown. The iron core 2 is arranged in a hollow support tube 3 . The hollow support tube 3 is - surrounded by two coil winding packets 11 - in this embodiment. The fastening stubs 12 are attached to the front of the support tube 3 and are used to fix the coil winding arrangement 1 in a stirring roller. In this exemplary embodiment, the electrical contacts 15 are guided inwards through the fastening stubs 12 to the coil winding packets. This electrical connection exists on both sides, ie on the left fastening stub 12 and on the right fastening stub 12. Different electrical phases are connected to the electrical contacts 15 on one side. In this embodiment, the coil winding arrangement can be supplied with a two-phase system. The at least two electrical contacts 15 have no electrical connection to one another. The coil winding packs 10 are surrounded by a protective tube 13 . Intermediate spaces present between the coil winding packages 10 and the protective tube 13 are filled with a filling compound 14 .

the 3 differs from 2 in that six coil winding packages are arranged along the first longitudinal extension. These coil winding packets each have only one layer 11a and a large number of turns 11b. Several slots 4 are present in the support tube 3 . The individual slots 4 are each separated from one another by a web 5 . These webs 5 have the function of preventing the support tube 3 from widening when the slot is being made. Like in the 3 As can be seen, the webs are arranged in such a way that, in a preferred embodiment, they are completely surrounded by a coil winding packet--that is, the webs 5 lie under a coil winding packet 10. In this embodiment variant, the iron core 2 is designed with a plurality of slots 4 in such a way that it also has a number of partial volumes of the Has iron core 2a, which fill the respective slots 4 almost completely. The partial volumes of the iron core 2a are represented by the vertical hatching. The coil winding packs 10 are surrounded by a protective tube 13 . Intermediate spaces present between the coil winding packages 10 and the protective tube 13 are filled with a filling compound 14 .

The cross section of a coil winding assembly is in 4 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 2a 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 packs 3 enclose the iron core 2 and the support tube 3, the coil winding packs 10 having two layers 11a. The coil winding packets 10 are enclosed by the protective tube 13, with a remaining space being filled with filling compound 14. Cooling channels 20 are arranged next to the iron core.

In figure 5 a cooling channel is present in the iron core 21 in addition to the cooling channels 20 . 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 in the iron core 21 are present.

the 6 shows an agitator roller 30 for a continuous casting plant. The agitator roller 30 includes the coil winding assembly 1 and a roller 31 which supports a strand produced by the continuous casting plant. The coil winding arrangement 1 is on both sides in a bearing block 36 - on the mounting stub 12 - fixed. The roller 31 is rotatably mounted on both sides. In this embodiment, the bearing 35 is arranged in the bearing block 36 . In the space between the coil winding assembly 1 and the roller 31 forms a Cooling channel 34 off. A coolant can be supplied through a coolant inflow 32 and removed again through a coolant outflow. The electrical contacts 15 are each connected to a coil winding package 10 .

In 7 a preferred embodiment of the coil winding packages 10 is shown. The coil winding packets consist of a layer 11a and a large number of turns 11b. The single-layer design ensures particularly good heat dissipation to the outside to the protective tube 13 or the insulating layer 13a (not shown).

In 8 an alternative embodiment of the coil winding packages 10 is shown. The coil winding packages 10 have two layers 11a and each layer 11a has a plurality of turns 11b.

In 9 a schematic representation of an embodiment of the coil winding arrangement is shown. The iron core 2 with a cross section and a first longitudinal extent is surrounded by a plurality of coil winding packages 10u, 10v, 10w along the first longitudinal extent. The u-phase coil winding pack 10u has a larger number of turns 11b than the v-phase coil winding pack 10v and the w-phase coil winding pack 10w. How from the 8 can be seen, two coil winding packages are connected to each of the three phases. The phase u and the phase w are each connected to a coil winding package 10u, 10w which is closest to the mounting stub. These coil winding packages 10u, 10w connected to the phases u and the phase w have a higher number of turns than the coil winding packages 10v connected to the phase v. The coil winding packets 10u, 10v, 10w connected to the individual phases u, v, w should have a number of turns that have almost the same current carrying capacity and almost the same inductance. For this In this embodiment, the number of coil winding packages is a multiple of three - e.g. three, six, nine, twelve, etc..

In 10 Figure 12 is another schematic representation of an embodiment of the invention. In this arrangement, only the phase u has an electrical connection with coil winding packages 10u, which are closest to the end faces of the iron core 2 or the fastening stub (not shown). The coil winding packages 10u connected to the phase u have a higher number of turns than the coil winding packages 10v, 10w connected to the phase v and the phase w.

In 11 advantageous embodiments of the connection contacts 15 are shown as a plan view. The space requirement on the attachment stub 12 for connecting three phases is small. On the one hand, it must be ensured that the required current can be routed 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 is pressed snugly against the electrical connection contact 15 with a fastening element 42—in the present example a nut.

In 12 is a plan and elevation of the in 10 connection contacts described 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. In a preferred embodiment, the ratio of bolt cross section 40a and fastening bolt cross section 41a is in the ratio of 1.7 to 4. Bolt 40 is advantageously designed with a round cross section and fastening bolt 41 has a thread. In the embodiment of the bolt 40 with a round Cross-section is a bolt diameter in the range of 14mm to 20mm in order to be able to transmit the currents required for the coil winding packages. A ratio of bolt diameter to fastening bolt thread diameter - whereby the nominal thread diameter is used here - is between 1.3 and 2.

In the 13 12 is an enlarged view of an electrical terminal including the bolt 40, the cable lug 43, the washer 44, and the fastener 42 screwed onto the fastener bolt 41. FIG.

In 14 a further preferred embodiment is shown, which differs from that in 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 15 a support tube 3 with a plurality of slots 4 is shown. The webs 5 are located between the slots 4. The partial volumes of the iron core can be inserted into the slots 4.

In 16 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 3mm and a height of 12mm.

Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention as claimed.

Reference List

1

coil winding assembly

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

4

slot

5

webs

6a

face

6b

mounting position

10

coil winding package

10u

Phase & Coil winding packages

10v

Phase v coil winding packs

10w

Phase w coil winding packs

11a

location

11b

turns

12

fastening stub

13a

protective layer

13

protective tube

14

filler

15

Electrical connection contacts

20

cooling channel

21

Cooling channel in the iron core

30

stirring roller

31

role

32

Inflow for coolant

33

drain for coolant

34

cooling channel

35

warehouse

36

bearing block

40

bolt

40a

bolt cross section

41

mounting bolt stub

41a

Fastening bolt stub cross-section

42

fastener

43

cable lug

44

washer

and

phase and

v

phase v

w

phase w

L1

First Longitudinal

L2

Second longitudinal extension

A

cross-section

Claims (15)

1. Electromagnetic coil arrangement for an electromagnetic stirrer roller of a continuous casting plant comprising an iron core (2) with an iron core cross section and a first longitudinal extent (L1), and at least two coil winding assemblies (10), two fastening stubs (12), at least two electrical connection contacts (15), which are connected in each case to at least one coil winding assembly (10), wherein

   - the at least two coil winding assemblies (10) enclose the iron core (2), in partial regions along the first longitudinal extent (L1),

   - wherein the coil winding assemblies (10) consist of a maximum of two layers (11a) lying one on top of the other, preferably only of one layer (11a), and also a multiplicity of turns (11b) lying next to one another,

   - wherein the coil winding assemblies (10) are designed in such a way that, for assembly, they can be pushed on from an end face of the iron core (2) up to an intended assembly position,

   - wherein the individual turns (11b) are coated with an insulating material,

   - wherein a protective layer (13a) encloses the coil winding assemblies (10),

   - wherein the fastening stubs (12) are arranged on the iron core (2) in each case at the end faces.
2. Electromagnetic coil arrangement according to Claim 1, wherein the turns (11b) have a rectangular cross section, wherein the dimension of the turn (11b) is greater 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 in the range from 1/3 to 1/8 is preferred, particularly preferably in a range from 1/4 to 1/6.
3. Electromagnetic coil arrangement according to Claim 1 or 2, wherein the iron core (2) has cooling channels (21).
4. Electromagnetic coil arrangement (1) according to Claims 1-3, wherein the protective layer (13a) is a protective tube (13) with a hollow cross section, preferably an annular cross section, which encloses coil winding assemblies (10), wherein intermediate spaces that are present between the protective tube (13) and the coil winding assemblies (10) are filled by means of filling compound (14).
5. Electromagnetic coil arrangement according to Claim 4, wherein the filling compound (14) has a thermal conductivity of greater than $0.1\frac{W}{mK}$

   

   , preferably greater than $\begin{array}{c}\\ 1\end{array}\frac{W}{mK}$

   

   .
6. Electromagnetic coil arrangement according to Claims 1-5, wherein the iron core (2) is arranged in a protective tube (3) with a second longitudinal extent.
7. Electromagnetic coil arrangement according to Claim 6, wherein the protective tube (3) has along the second longitudinal extent (L2) at least one slit (4), in particular at least two, preferably at least four, particularly preferably at least six, most particularly preferably eight slits (4), with in each case a predetermined slit area, and the iron core (2) is formed in such a way that in each case a partial volume of the iron core (2a) can be pushed into the slits (4), preferably the respective partial volume/volumes of the iron core (2a) completely fill(s) the slits (4).
8. Electromagnetic coil arrangement according to Claims 1-7, wherein cooling channels (20) are arranged within the supporting tube (3) alongside the iron core (2).
9. Electromagnetic coil arrangement according to Claim 7, wherein the slit area is rectangular.
10. Electromagnetic coil arrangement according to Claims 1-9, wherein the electrical connection contacts (15) have a bolt (40) with a bolt cross-sectional area (40a) which can transmit required energy to the winding assemblies, and also 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.
11. Electromagnetic coil arrangement according to Claims 1-10, wherein the coil winding assemblies (10) closest to the fastening stubs (12) in each case and all of the coil winding assemblies (10) electrically connected to them have a greater total number of turns than a total number of turns of all the other coil winding assemblies (10) that are respectively electrically connected to one another.
12. Electromagnetic coil arrangement according to Claims 1-11, wherein the said arrangement has three electrical connection contacts (15) and has a number of coil winding assemblies (10), wherein the number corresponds to a multiple of three plus two and the coil winding assemblies (10) closest to the fastening stubs (12) in each case have a smaller number of turns than the remaining coil winding assemblies (10).
13. Electromagnetic coil arrangement according to Claims 1-11, wherein said arrangement has three electrical connection contacts (15) and coil winding assemblies (10) with a number of at least three or a multiple of three, wherein the coil winding assemblies (10) closest to the fastening stubs (41) in each case have a greater number of turns than the remaining coil winding assemblies (10).
14. Electromagnetic stirrer roller for a continuous casting plant for producing 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 inflow for coolant (32),

    - an outflow for coolant (33),

    wherein the electromagnetic coil arrangement (1) according to Claims 1-13 is arranged within the roller (31) and said arrangement is fixed on both sides on a bearing block (36), wherein a cooling channel (20), which is connected to the inflow (31) and the outflow (32), is formed between the tube (31) and the coil arrangement (1).
15. Electromagnetic stirrer roller according to Claim 14, wherein the roller (31) is rotatably mounted on both sides on the bearing block.

Images