JPH0213922B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for induction heating a laminated iron core.

Conventionally, there is an induction heating device for a laminated iron core as shown in FIG. First, the principle of heating in this type of apparatus will be explained with reference to FIG. 2, which shows the main part of FIG. 1.

When an alternating current is passed through the heating coil 1, the magnetic flux φ changes, and an induced current is generated concentrated at a certain depth from the outer peripheral surface of the laminated iron core 2. The thickness of the layer where this current is concentrated is called the current penetration stylus, and if this is expressed in δ (cm), it is given by the following equation.

Here, ρ: Specific resistance (Ωcm) of the heated object (laminated core) μ: Magnetic permeability of the heated object (laminated core) f: Frequency of alternating current For iron core material at room temperature, ρ = 10 × 10 ^-8 Ωcm, μ =100
The induced current flows in a concentrated manner within the depth of δ given by the above equation based on the frequency of the alternating current, and near the outer peripheral surface of the laminated core where heat is generated, the resistivity increases as the temperature rises and reaches the A2 transformation point (approximately 750 ℃), ρ=1000×
10 ^-8 Ωcm, while the magnetic permeability is μ= at the A2 transformation point.
Becomes 1.

As a result, the induced current flows through the part of the laminated core that enters inside from the outer peripheral surface, generating heat in that part, and the heat generating layer gradually moves inside the laminated core, resulting in the entire laminated core being heated. Ru.

Now, in the device shown in FIG. 1, a heating coil 1 is placed vertically, and a heated laminated core is sequentially taken out from below by a handling device consisting of a clamper cylinder 3, a horizontal push cylinder 4, and a laminated core receiving cylinder 5. ing. Therefore, since batch processing is required, changes in the state of the laminated core (at room temperature,
(High temperature) causes large fluctuations in the load, which causes fluctuations in the power factor of the power supply.

In order to maintain a good power factor, it is necessary to change the capacitance of a capacitor in the electric circuit, which complicates control. On the other hand, if the deterioration of the power factor is ignored, there is a problem in that the reactive current increases. Also, because one side of the laminated core is lifted by the magnetic force, a presser weight is required.

In addition, as other conventional devices of this type,
As shown in the figure, the heating coil 6 is placed horizontally, the laminated iron core is pushed into the guide 8 around which the heating coil 6 is wound by a pusher cylinder 7, and the extruded laminated iron core is carried out by a conveyor 9. There is something I did.

Although this device is also a batch type, it is close to a continuous type, so it is easier to control the power supply than in the case of the above-mentioned device. However, the guide 8 must be strong enough to prevent the laminated core from turning due to magnetic force, and must also serve as a guard to prevent the laminated core from hitting the heating coil 6. The structure is difficult, and the guide 8 and conveyor 9 It is also difficult to connect the parts.
Furthermore, if the laminated core is thin, care must be taken to prevent it from tipping over during transfer.

Similarly, as a conventional example in which the heating coil is placed horizontally, the one described in Japanese Patent Application Laid-Open No. 47-40102 is known. This annealing method involves arranging the motor cores in a cylindrical row in the axial direction, continuously inserting them into a heating furnace with induction coils wrapped around the cylindrical furnace wall, and rapidly heating them using induction heating at commercial frequencies. It was designed to do so. however,
In the annealing method described in JP-A-47-40102, the motor core is conveyed in the same direction as its thickness direction (axial direction).
As mentioned above, the heating of the motor core is carried out by the heating layer moving sequentially from the outer circumference of the core to the inner circumference of the core.Therefore, due to the relationship between the heating depth and the frequency of the alternating current, The problem was that it was subject to restrictions.

The above-mentioned conventional induction heating devices for laminated iron cores are all designed to carry the laminated state into the heating coil, but as a device for induction heating other materials to be heated, as shown in Fig. 4, , material to be heated (flat plate)
There is one in which an inductor 11 is installed parallel to the heated surface 10a of the heater.

This device uses the same heating principle, and changes the magnetic flux φ by passing an alternating current through the inductor 11 (the current flows alternately from the front to the paper and from the paper to the front), and generates an induced current on the surface of the flat plate. , heat is generated due to the specific resistance of the flat plate 10.

When the flat plate 10 is moved in the horizontal direction, the flat plate surface is heated continuously and uniformly. This device is used in conjunction with a water cooling device for induction hardening. If the flat plate 10 is fixed, the heat generating layer will gradually move deeper, but this will be inefficient.

When this type of device is applied to heating a laminated iron core, a configuration as shown in FIG. 5 can be considered. However, since the laminated core 12 is made up of thin veneers (0.35 mm to 0.64 mm thick) with insulation between the layers, eddy currents are generated in each veneer and do not reach a large value, and heat generation does not occur. Since it is generated by this induced eddy current, the amount of heat generated is small.

Therefore, although this type of device can heat only the vicinity of the dielectric 11, it is impossible to heat the entire laminated core.

The present invention has been made in view of the above-mentioned circumstances, and is capable of efficiently performing induction heating while continuously moving the laminated iron core, and is capable of induction heating of the laminated iron core without being restricted by the frequency of the alternating current. An object of the present invention is to provide a heating method and apparatus.

According to this invention, a plurality of pairs of heating inductors are arranged opposite each other, and an alternating current is passed through the coils of the plurality of pairs of heating inductors such that the polarities of the opposing heating inductors are opposite to each other. At the same time, the direction of the magnetic flux generated between the plurality of pairs of heating inductors is made to match the thickness direction of the laminated core, and the direction of the magnetic flux generated between the plurality of pairs of heating inductors is aligned between the plurality of pairs of heating inductors from the direction perpendicular to the thickness direction of the laminated core. The laminated iron core is continuously conveyed, and the entire laminated iron core is induction heated while the induction heating portion of the laminated iron core by the heating inductor is sequentially transferred.

According to this invention, a plurality of pairs of heating inductors are arranged opposite each other, and an alternating current is applied to the coils of the plurality of pairs of heating inductors such that the polarities of the opposing heating inductors are opposite to each other. At the same time, the laminated core is continuously conveyed between the plurality of pairs of heating inductors while aligning the direction of magnetic flux generated between the plurality of pairs of heating inductors with the thickness direction of the laminated core;
The laminated core is induction heated while sequentially moving the induction heating portion of the laminated core by each pair of heating inductors.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 6a and 6b are a front view and a side view, respectively, showing the relationship between the heating inductor and the laminated core according to the present invention. In the same figure, a heating inductor 20
a and 20b are arranged opposite to each other, and their cross-sectional shape is rectangular, and the long side is slightly longer than the diameter of the laminated core 21, and the short side is sufficiently shorter than the long side (see Fig. 6b). ).

By passing an alternating current through the coils of the heating inductors 20a and 20b, magnetic poles are generated. The polarity of the inductor and the direction of the magnetic flux φ shown in FIG. 6a are reversed at the next moment. Further, the laminated core 21 is arranged between the heating inductors (the sixth Diagram a
), and is continuously conveyed in a direction perpendicular to the thickness direction of the laminated core 21, that is, in the direction of arrow A (see FIG. 6b).

Next, the principle of heating according to the present invention will be explained with reference to FIG. By passing an alternating current through the coil of the inductor, a magnetic flux φ is generated between the inductors, and a vortex is generated in each core (single plate) 21a of the laminated core 21 in a direction perpendicular to the magnetic flux, that is, in the width direction of the single plate 21a. A current is induced and each core in that area generates heat.

By continuously moving the laminated core 21, the entire laminated core 21 is induction heated while sequentially moving the induction heating portions. In addition, even if the iron core is partially heated, when it reaches the A2 transformation point (around 750℃), the magnetic permeability becomes μ = 1,
The heated portion gradually shifts toward μ≫1 without being overheated.

That is, while the conventional technology moves the heating layer sequentially from the outer periphery to the inside of the laminated core, the present invention heats a part of the laminated core while continuously moving the laminated core, thereby gradually applying the heating layer to the entire laminated core. It is something.

Therefore, in the prior art, the frequency of the alternating current was restricted due to the relationship with the heating depth, but in the case of the present invention, the most efficient frequency can be applied. Furthermore, since the laminated core is moved continuously, the integrated work of insertion, heating, soaking, cooling, and removal can be easily performed.

Figures 8a and 8b are a side view and a front view showing the relationship between two pairs of heating inductors and a laminated core.
In the figure, adjacent heating inductors 31a and 3
2a, 31b and 32b are arranged so that the cores 33 and 34 partially overlap and the two cover the outer diameter of the laminated iron core 35, and the coils 36, 32b are arranged so that the polarities are reversed. 37 is connected to a high frequency power source 38. Of course, the opposing heating inductor 31
a and 31b, and 32a and 32b are also connected to a high frequency power source so that their polarities are reversed (not shown).

The load acting on the two pairs of heating inductors, that is, the portion where the inductor cores 33, 34 and the laminated core 35 overlap (the shaded portion) shown in FIGS. 10a to 10f.
The area is substantially constant regardless of the position of the laminated core 35, which facilitates electrical control. This utilizes the shape characteristics of a laminated core with a hollow center.

On the other hand, FIGS. 9a and 9b are a side view and a front view showing the relationship between two pairs of heating inductors and a laminated core, in which two pairs of heating inductors 41a, 41b and 42 are shown.
Each of the cores a and 42b has a size that can cover the outer diameter of the laminated core 43. Note that the connection between the coil of the heating inductor and the high frequency power source 44 is the same as in the case of the heating inductors 31a and 32a described above.

Although the load acting on these two pairs of heating inductors is not as great as that of the heating inductors shown in Fig. 8a and b,
It remains almost constant regardless of the position of the laminated core 43.

Although FIG. 8 and FIG. 9 each show two pairs of heating inductors, several pairs to more than ten pairs of heating inductors may be arranged in parallel as necessary.

Figures 11a and 11b are side views of eight pairs of heating inductors arranged in parallel, and Figure 11c
is a plan view of FIGS. 11a and 11b; Note that Fig. 11a shows an arrangement of heating inductors that cover the outer diameter of a laminated core with two adjacent heating inductors, and Fig. 11b shows an arrangement of heating inductors that cover the outer diameter of a laminated core with one heating inductor. This is an array of heating inductors that cover the outer diameter.

Next, a method of connecting each inductor coil to a high frequency power source when a plurality of pairs of heating inductors are arranged as described above will be described.

FIG. 12a is a system diagram showing an example of connection between a plurality of pairs of heating inductor coils and a high frequency power source, and FIG. 12b is a wiring diagram thereof.

In this case, the coils L ₁ to _{L 8} and R ₁ to _{R 8} are replaced by the first group of coils L ₁ , R ₁ , L ₂ , R ₂ and the second group of coils L ₃ , R ₃ , L ₄ , and R _{4 .} , the third group of coils L ₅ , R ₅ , L ₆ , R ₆ and the fourth group of coils L ₇ , R ₇ , L ₈ , R ₈ , the coils are connected in series for each group, and the reactor r ₁ to _r4 , and are connected in series with the reactors corresponding to the groups, and each connected group is connected in parallel to the high frequency power source 50.

Therefore, reactor control of the coils can be performed by group. It goes without saying that the wires are connected so that the directions of current flowing through the opposing coils are the same. Further, the wires are connected so that the directions of current flowing through adjacent coils are different from each other (see FIG. 12a).

FIG. 13a is a system diagram showing an example of the connection between a plurality of pairs of heating inductor coils, a high frequency power source, and other connections, and FIG. 13b is a wiring diagram thereof.

In this case, connect the opposing coils in series and
Each group is connected in parallel to the high frequency power source 51 with a reactor attached.

Note that the wiring method is not limited to the above example,
Various wiring methods can be considered, and depending on the number of coils, current value, etc., it is also possible to connect all the coils in series or in parallel. Furthermore, if reactor control is not required, it may be possible to omit the reactor from part or the entire circuit.

Furthermore, although the reactor directly adjusts the power, it becomes possible to control the temperature of the laminated core by adjusting the input power.

FIG. 14 is a block diagram showing an example of a temperature control device for a laminated core. In the figure, a temperature detector 61 detects the temperature of a laminated iron core 63 that is induction heated by a heating inductor 62, and converts the detected value into A/
The signal is input to a computer 65 via a D converter 64. The computer 65 calculates an input power correction value, that is, a reactor correction value, from this temperature data, various data given in advance, and calculation formulas, and controls the reactor 66 based on this reactor correction value. In this way, it becomes possible to control the heating temperature of the laminated core 63 (obtaining a desired temperature increase using each heating inductor).

Next, the detailed structure of the device of the present invention will be explained.

FIG. 15 and FIG. 16 are a front sectional view and a perspective view, respectively, showing an embodiment of a heating inductor according to the present invention. The core 75 is constructed by bundling wire rods 76 into a substantially C-shape and further surrounding it with a copper film 77. As an example of the wire rod 76, a piano wire (about 0.01 mm in diameter) that has been subjected to a Parkerizing treatment is used. Alternatively, a small diameter copper pipe (not shown) for water cooling may be inserted into the core 75.

On the other hand, opposing heating inductors 78a and 78b
is constructed by surrounding both ends of the core 75 with coils (square copper tubes) 79 and 80, respectively (see FIG. 16). Note that it is also possible to cool the coils 79, 80 by flowing water through them.

FIGS. 17 and 18 are a front sectional view and a perspective view, respectively, showing other embodiments of the heating inductor according to the present invention. The core 85 is constructed by laminating substantially C-shaped thin plates 86 and further surrounding them with a copper film 87. As an example of the thin plate material 86, a silicon steel plate (about 0.1 mm thick) coated with an insulation coating is used.

On the other hand, a pair of opposing heating inductors 88a, 8
8b is constructed by surrounding both ends of the core 85 with coils (square copper tubes) 89 and 90, respectively (see FIG. 18).

The heating inductor 78 facing as described above
By configuring a, 78b and 88a, 88b, the magnetic path generated in the inductor can be closed by the core, and leakage magnetic flux can be reduced. Furthermore, by surrounding the core with a copper film, leakage is doubly prevented. Note that the former heating inductors 78a and 78b are used when the frequency is relatively high, and the latter heating inductors 88a and 78b are used when the frequency is relatively high.
88b is preferably used when the frequency is relatively low.

Further, in each of the above embodiments, a closed magnetic path is constructed between a pair of inductors, but a closed magnetic path can also be constructed between two pairs of inductors.

FIGS. 19 and 20 are a plan sectional view and a perspective view, respectively, showing an embodiment of a heating inductor according to the present invention, which constitutes a closed magnetic path between two pairs of inductors. As is clear from these figures, adjacent inductors are connected by a substantially U-shaped core 90. The structure of the core 90 is the same as that of the core 75 shown in FIG. 15, so a detailed explanation will be omitted here. Furthermore, it goes without saying that the currents flowing through the coils of adjacent inductors should be in opposite directions.

FIGS. 21 and 22 are a plan sectional view and a perspective view, respectively, showing another embodiment of the heating inductor according to the present invention, which constitutes a closed magnetic path between two pairs of inductors. In this case as well, adjacent inductors are connected by a substantially U-shaped core 91 in the same manner as described above. Further, since the structure of the core 91 is the same as that of the core 85 shown in FIG. 17, detailed explanation will be omitted here.

The heating inductor in which a closed magnetic path is formed between two pairs of inductors as described above has the advantage that the opposing inductors can be spaced apart depending on the thickness of the laminated core. Application in which adjacent inductors are shifted as shown in FIG. 11a is not recommended because the structure will be distorted.

Next, an example of a conveying means for carrying the laminated core in and out between the plurality of pairs of heating inductors will be described.

As shown in FIG. 23, this conveyance means includes multiple pairs of heating inductors 100a, 100b, 101a.
and 101b, . . . , and a case 105 in which a case body 103 is attached to the conveyor belt 102 and accommodates a laminated core 106.

The material used for the case 105 is one that has strength at high temperatures (approximately 900° C.), and is unaffected by magnetic fields and has electrical insulation properties. for example,
Hard porcelain etc. can be used. Also, the inner width of the case should be the same as the height of the laminated core, or the inner width of the case should be made with a margin for flexibility, and a distance piece should be used.

By housing the laminated core 106 in this case 105, the laminated core will not rotate due to magnetism even if the core passes through a high-frequency magnetic field.
Furthermore, the iron core and the coil can be electrically insulated.

Further, as shown in FIG. 24, the case 105 can be kept airtight by providing a sand seal (for example, asbestos powder) 107 between the case body 103 and the case lid 104. Further, the case lid 104 is provided with a gas supply hole 108 with a lid and a gas vent hole 109 with a non-returnable gas vent.

Therefore, when heating in an atmosphere of a gas heavier than air (e.g. carbon dioxide), the laminated iron core is housed in this case 105 and the covered gas supply hole 1 is
The above gas may be injected from 08 onwards.

25 and 26 show another embodiment of the case, in which a case bottom plate 113 is attached to a conveyor belt 112, and a sand seal 117 is interposed between the case bottom plate 113 and a case main body 114. It is designed to be covered with. A gas supply hole 118 with a lid is provided in the upper part of the case body 114 of this case 115, and a gas vent hole 119 with a non-returning cover is provided in the case bottom plate 113.

Therefore, when heating in an atmosphere of a gas lighter than air (for example, nitrogen gas), the laminated core is housed in this case 115 and the covered gas supply hole 1 is
The above gas may be injected from 18. In addition, _N2
In the case of atmosphere annealing, it has traditionally been difficult to shut off air (to prevent air from entering the furnace) when inserting and extracting the laminated core into the furnace, especially when the laminated core has uneven surfaces. Using the above case makes it extremely easy.

As explained above, according to the present invention, the direction of the magnetic flux generated between the plurality of pairs of heating inductors is made to coincide with the thickness direction of the laminated iron core, and the laminated iron is separated from the direction perpendicular to the thickness direction. Since the laminated iron core is continuously conveyed between the plurality of pairs of heating inductors, and the induction heating portion of the laminated iron core is sequentially transferred by the heating inductors, the entire laminated iron core is inductively heated. Heating can be performed efficiently. Furthermore, since there is no restriction on the frequency of the alternating current, the most efficient frequency can be applied. In addition, since the laminated core is moved continuously, it is possible to easily perform the integrated work of insertion, heating, soaking, cooling, and removal, and it is also possible to even out the load applied to the power supply. .

For example, among multiple pairs of heating inductors, between the first inductor, laminated cores at room temperature are brought in one after another, and the specific resistance of the core is always ρ = 10 × 10 ^-6 Ωcm,
Magnetic permeability μ = 100, but between the final inductors, the iron core is gradually heated to a high temperature and is brought in, so the specific resistance of the iron core is always ρ≒
1000×10 ^-6 Ωcm, magnetic permeability μ≒1. That is, as long as the specifications of the laminated core are constant, the load acting on each inductor (each coil) is approximately constant, and it is easy to control all the coils at once or separately.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an example of a conventional laminated core induction heating device, Fig. 2 a and b are a front view and a plan view showing the main parts of Fig. 1, respectively, and Fig. 3 is a conventional laminated core. A schematic configuration diagram showing another example of the induction heating device, FIG. 4 is a diagram in which the heating inductor and the heated surface of the heated material are installed parallel to each other, and FIG. 5 is a schematic diagram showing another example of the induction heating device in FIG. Diagram when laminated core is applied,
6a and 6b are front and side views respectively showing the relationship between the heating inductor and the laminated core according to the present invention, FIG. 7 is a diagram used to explain the heating principle according to the present invention, and FIG. Figures a and b are front views and front views showing the relationship between two pairs of heating inductors and a laminated core, and Figures a and b are other views showing the relationship between two pairs of heating inductors and a laminated core. A side view and a front view, FIGS.
Figures 1a and 1b are side views of eight pairs of heating inductors arranged in parallel, Figure 11c is Figure 11a.
FIG. 12a is a system diagram showing an example of connection between the coils of multiple heating inductors and a high frequency power source, FIG. 12b is a connection diagram of FIG. 12a, and FIG.
Figure 3a is a system diagram showing another connection example between multiple pairs of heating inductor coils and a high-frequency power source, Figure 13b is the connection diagram of Figure 13a, and Figure 14 is a temperature control device for a laminated iron core. Block diagrams showing an example, Figures 15 and 16, Figures 17 and 18, Figures 19 and 20.
21 and 22 are respectively a sectional view and a perspective view thereof showing an embodiment of a heating inductor according to the present invention, and FIGS. 23a and 23b are respectively an embodiment of a conveying means according to the present invention. 24 is an enlarged view of the main part of FIG. 23b, and FIGS. 25a and b are side sectional views of the main part of other embodiments of the conveyance means according to the present invention, respectively. and a front sectional view, and FIG. 26 is an enlarged view of the main part of FIG. 25b. 20a, 20b, 31a, 31b, 32a, 3
2b, 41a, 41b, 42a, 42b, 62,
78a, 78b, 88a, 88b, 100a, 1
00b, 101a, 101b...Heating inductor,
21, 35, 43, 63, 106...Laminated core,
33, 34, 75, 85, 90, 91...core,
36, 37, L ₁ ~ L ₈ R ₁ ~ R ₈ , 79, 80, 89,
90... Coil, 38, 44, 50, 51... High frequency power supply, 61... Temperature detector, 65... Computer, 66, _r1 to _r8 ... Reactor, 76...
Wire rod, 77, 87...Copper film, 86...Thin plate material, 1
02,112...conveyor belt, 103,11
4...Case body, 104...Case lid, 10
5,115...Case, 107,117...Sand seal, 108,118...Gas supply hole with lid, 109,119...Gas vent hole with non-returnable gas,
113...Case bottom plate.

Claims (1)

[Scope of Claims] 1 A plurality of pairs of heating inductors are arranged opposite each other, and an alternating current is applied to the coils of the plurality of pairs of heating inductors such that the polarities of the opposing heating inductors are opposite to each other. and heating the plurality of pairs of laminated iron cores from a direction perpendicular to the thickness direction by aligning the direction of magnetic flux generated between the plurality of pairs of opposing heating inductors with the thickness direction of the laminated iron core. A method of induction heating a laminated iron core, characterized in that the entire laminated iron core is induction heated while being conveyed continuously between heating inductors, and the induction heating portion of the laminated iron core is sequentially transferred by each pair of heating inductors. . 2. A plurality of pairs of heating inductors arranged in parallel, a current supply means for supplying an alternating current to the coils of the heating inductors so that the polarities of the opposing heating inductors are opposite to each other, and opposing heating inductors. Lamination in which the direction of magnetic flux generated between the inductors matches the thickness direction of the laminated core, and the laminated core is continuously conveyed between the plurality of pairs of heating inductors from a direction perpendicular to the thickness direction. An induction heating device for a laminated iron core, comprising a means for transporting the iron core. 3. The laminated iron core induction heating device according to claim 2, wherein the plurality of pairs of heating inductors are comprised of a plurality of substantially C-shaped cores and coils wound around both ends of the cores. 4. The plurality of pairs of heating inductors are arranged in parallel so that the induction heating portions of the laminated core by the adjacent heating inductors partially overlap and are staggered. induction heating equipment for laminated iron cores. 5. The laminated iron core induction heating device according to claim 3, wherein the substantially C-shaped core is formed by bundling wires into a substantially C-shape and surrounding it with a copper film. 6. The induction heating device for a laminated iron core according to claim 5, wherein the wire is a piano wire having a diameter of about 0.01 mm and subjected to a parkerizing treatment. 7. The laminated iron core according to claim 3, wherein the substantially C-shaped core is formed by laminating substantially C-shaped silicon steel plates having a thickness of about 0.1 mm with an insulating coating, and surrounding this with a steel film. Induction heating device. 8 The plurality of pairs of heating inductors include a plurality of substantially U-shaped cores in which both ends of two substantially U-shaped cores are arranged side by side as a set, and a coil wound around both ends of the cores. An induction heating device for a laminated iron core according to claim 2, comprising: 9. The induction heating device for a laminated iron core according to claim 8, wherein the opposing substantially U-shaped cores of each set are spaced apart according to the thickness of the laminated iron core. 10 The substantially U-shaped core is formed by bundling wire rods into a substantially U-shaped core.
9. An induction heating device for a laminated iron core according to claim 8, which is formed into a letter shape and surrounded by a copper film. 11. The induction heating device for a laminated iron core according to claim 10, wherein the wire is a piano wire having a diameter of about 0.01 mm and subjected to a parkerizing treatment. 12. The laminated iron core according to claim 8, wherein the substantially U-shaped core is formed by laminating substantially U-shaped silicon steel plates with a thickness of about 0.1 mm with an insulating coating, and surrounding this with a steel film. Induction heating device. 13. Claim 2, wherein the current supply means divides the coils of the heating inductor into groups and supplies current through a reactor for each group.
An induction heating device for a laminated iron core as described in . 14. The laminated core guide according to claim 2, wherein the conveying means comprises a conveyor in which a conveyor belt passes between opposing heating inductors, and a case attached to the conveyor belt and housing the laminated core. heating device. 15. The laminated iron core induction heating device according to claim 14, wherein the case is made of hard porcelain. 16. The laminated iron core induction heating device according to claim 14, wherein the case is formed with a gas supply hole and a gas vent hole.