JPS59151793A - Spiral coil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spiral coil made of multiple parallel conductors that conduct a large current.

Coils of this type are used, for example, to inductively heat molten metal, spaced apart on its free surface, up to 100 degrees Celsius.
Since the coil is installed near high-temperature molten metal at around 0 degrees Celsius, only insulating materials that can withstand high temperatures can be used. Therefore, since it is difficult to use a high voltage, a large current coil must be used. Therefore, in order to obtain a large conductor area for carrying a large current and also to prevent an increase in stray loss due to current unbalance and eddy current, a method is used in which multiple conductors are connected in parallel. It is desired to develop a high-current spiral coil that allows currents of the same magnitude to flow.

Figure 1 is a structural diagram of an induction heating device for molten metal. An alternating magnetic field is generated by the current spiral coil 3, and the eddy current induced in the molten metal 2 heats the molten metal. When using multiple parallel conductors for the spiral coil 3, in order to cause the same amount of current to flow through all parallel conductors, it is necessary to balance each conductor magnetically. The characteristics differ depending on the method.

FIGS. 2 and 3 are structural diagrams of conventional spiral coils, in which the conductor is represented by a single line. In Fig. 2, the spiral coil 3 is formed by winding three partial coils 4, 5, and 6 into a disk shape such that the outer circumferential surface of the inner coil is in contact with the inner circumferential surface of the outer coil. Insulation is maintained between adjacent conductors by interposing an insulating material between the eyebrows. In addition, the starting end and ending end of each partial coil are a pair of reciprocating lead wires 4a,
5a.

6a, each partial coil is connected to the bus bar 7 in parallel.
It is connected to the. In order to magnetically balance each partial coil of the above-mentioned spiral coil, there is a method of changing the number of turns of each partial coil by a fraction of a turn (referred to as a non-integer turn), but by making it a non-integer turn coil, Since the lead-out positions of the pair of reciprocating lead wires are separated from each other, the effect of canceling out the magnetic field in the lead wire portion cannot be expected, and there is a drawback that the voltage drop of the lead wire becomes large.

In FIG. 3, the spiral coil 3 consists of three partial coils 8, 9.
．． 10 are stacked in parallel in the radial direction with an interlayer insulating material (not shown) interposed therebetween, and are wound three turns with section a as the starting end and section b as the terminal end.
Three partial coils 8, 9 and 10 are connected in parallel and drawn out using lb. In the spiral coil 3 in Fig. 3, since the lengths of the conductors forming the partial coils 8, 9, and 10 are different, each partial coil is not magnetically balanced, and therefore the current flowing through each partial coil is not equal. , causing so-called current imbalance. As a countermeasure against this problem, a method is known in which the relative positions of the partial coils 8, 9, and 10 are rearranged to obtain magnetic equilibrium, as shown in FIG. However, it is difficult to fabricate the transposed portion, and since the difference in radius per turn is large, the shape of the coil deviates considerably from a circular shape, resulting in a mechanically weak structure.

Further, it is not possible to change the number of turns of each partial coil for the same reason as explained with reference to FIG.

The present invention was made in view of the above-mentioned situation, and it is an object of the present invention to provide a high-current spiral coil made of multiple parallel conductors that can effectively maintain magnetic balance for any number of parallel conductors.

According to the present invention, a plurality of partial coils are formed by sequentially winding a conductor for conducting current into a disk shape through an interlayer insulating material, and the partial coils are successively wound in contact with the outer circumferential surface of the partial coil to form a plurality of partial coils. A large current coil connected in parallel to each other, each partial coil being wound with a non-integer number of turns, and formed so that the total number of turns is an integer number of turns,
The terminal end of one partial coil and the starting end of the other partial coil that are adjacent to each other are drawn out from close positions on the same circumference by a pair of lead wires, and the starting end of the innermost partial coil and the terminal end of the outermost partial coil and are arranged on one normal line and 1
The pair of lead wires are drawn out in parallel and close to each other in the axial or normal direction, and each pair of lead wires is connected in parallel to each other. more accomplished.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 5 is a structural diagram of a spiral coil showing an embodiment of the present invention. In the figure, the spiral coil has partial coils 21, 22, and 23 wound one on top of the other in order from the inner circumferential side.
The starting end of the partial coil 23 and the terminal end of the partial coil 23 are located approximately on one normal line at the L position, and are drawn out in the normal direction by a pair of lead wires 24.25, and the partial coil 21, 22.23
is formed into an integral number of turns with a total number of turns of 10 turns.

Further, the terminal end of the partial coil 21 and the starting end of the partial coil 22 are at a position N which is offset by 2 degrees from the position on one circumference of the fourth turn from the inside, and are connected in the normal direction by a pair of lead wires 26 and 27. It is pulled out to a position separated by light on the outer circumference of the spiral coil. In addition, the terminal end of the partial coil 22 and the starting end of the partial coil 23 are located at the M position, which is 01 degrees shifted from the L position of the fourth turn from the outside, and the pair of lead wires 28.2
9 in the normal direction. And the three pairs of lead wires are 24 and 26.2g to the busbar 30a, and 2g to the busbar 30a.
The partial coils 21, 22, and 23 are connected in parallel by connecting the coils 5, 27, and 29 to the bus bar -30b. The number of turns of each partial coil and the lead extraction position are determined so that each partial coil is magnetically balanced, and specifically, the magnetic flux linkage is the same when the same amount of current is passed through each partial coil. It will be done. In the case of Fig. 5, the total number of turns of the spiral coil is an integer coil with 10 turns, and one turn of these is used as an adjustment turn to place the lead wires at approximately equal angles on the circumference.
, N is shown, and the geometric number of turns of each partial coil is (
3-θ1/360) turn, (3(θ1+θ2)/3
60) turns, and (4-θ2/360) turns, which are non-integer turns.

In addition, the current balancing reactors 31, 32, and 33, through which the two leads of each pair pass, are used when there is even a slight magnetic unbalance in each partial coil, or when the surface height of the molten metal changes. When the magnetic flux distribution changes and the magnetic balance between the parallel coils shifts, this reactor absorbs the unbalance and causes the same current to flow in different directions to adjacent leads. However, if the unbalanced amount of current flowing through each partial coil is within an allowable range even without the reactor, the reactor may be omitted. In the case of Figure 5, each pair of lead wires is routed a fairly long distance to the point where they are connected to the busbar, but the pair of lead wires are close to each other and parallel to each other.
The magnetic flux generated by the current flowing through the lead wires is cancel each other out, and the magnetic flux linkage becomes almost zero. Therefore, the actance of the pair of lead wires becomes small, and the potential drop at the lead wire portion can be reduced to a negligible level.

However, since the terminal voltage of the spiral coil is applied to the two lead wires, the insulation between the lead wires is formed to sufficiently withstand this voltage.

FIG. 6 is a structural diagram of a lead wire extraction portion of a spiral coil according to the present invention, both of which are examples in which the conductor of the spiral coil is directly utilized as a lead wire and is extracted. In (a), the conductor cross section is square or circular, and the ratio of the long side to the short side is close to 1. The two conductors 41° and 42 are bent at right angles to the axial direction at the extraction position, and At this point, it is bent again at right angles and pulled out horizontally and in the normal direction. An insulating material 43 is interposed between the conductors in the portion where the conductors face in the axial direction, and a band 44 is used to tighten the heat-resistant insulating material to mechanically fix the conductor. In addition, (b) shows a case where the cross-sectional shape of the conductor is flat, and in this case, simply arranging the conductors horizontally as in (a) does not make it possible to sufficiently reduce the adhesive actance of the lead wire, so conductors 45 and 46 are made of insulating material. The reactance can be reduced by axially overlapping each other through the axial direction. In this case, as in the case (a), the coil is mechanically fixed using a band for tightening.

Next, regarding the magnetic balance in the above-mentioned example, the fifth
This will be explained in detail using the figures again. In the figure, the outermost 1
Turn the coil of turn 101. If the innermost turns are respectively named 102.103°...110, then the partial coil 23 is the turn coil 101.102.
．． The entire circumference of 103 and the turn coil 104 (θ1/360
) is composed of Zhou and Zhou. Since the coils are coaxially arranged, the magnetic flux is distributed coaxially and there is no change in the angle θ1 direction, so the magnetic flux that intersects the (θ1/360) circumference of the turn coil 104 is interlinked with the entire circumference of the turn coil 104. It is (θ1/360) times the intersecting magnetic flux. Therefore, the number of magnetic flux linkages φ3 of the partial coil 23 is calculated as follows: φ3=φ101+φ102+φ103 + (θ1/3
60) φ104 = +11. In the same way,
Interlinkage magnetic flux φ2 of partial coils 22, 21. For φ1, on the other hand, φ2=((360-01)/360)φ104+φ10
5+φ106+(θ2/360)φ107, -
+21φ1=[(360-
θ2)/360]φ107+φ108+φ109+φ1
10 (3). Let the total interlinkage magnetic flux φT be φ1. If it is the sum of φ2 and φ3, this becomes the following equation, and is independent of the lead pullout position.

φT=φ101+φ102+・・・・・・・・・10φ1
10 ----=-,,-(41 On the other hand, let's consider the magnetic flux that interlinks with the lead leads.

In Fig. 7, considering only the arrangement of turn coils with one turn or less and their lead leads, turn coil R
Assume that the PC is chipped at an angle of 0 degrees at the BC part and has a drawer lead sticking out, and if the leads are BA and CD, then the drawer leads BA and CD are facing in the normal direction,
Points A and D are positioned far enough apart that the magnetic flux generated by the current flowing through the coil is sufficiently small. Since the magnetic flux has a coaxial distribution and always forms a closed loop, the sum of the magnetic flux passing through the pentagonal BOCDIHA portion is zero. Therefore, the magnetic flux interlinking to the area surrounded by ARPCDIH is equal to the magnetic flux interlinking to the area surrounded by fan-shaped 0BPC, so it is proportionally reduced by the angle θ formed by the extraction positions B and C of the extraction lead. The flux linkage is obtained.

For example, B
If the lead wires are drawn out in parallel like E and CF, the magnetic flux linkage of the fan-shaped BOC and the magnetic flux linkage of BCPB are not equal, so the magnetic flux linkage of the part surrounded by EBPCF is:
Since the value is not determined only by the angle θ formed by the lead pull-out positions B and C, the object of the present invention cannot be achieved.

In this way, by drawing out the lead in the normal direction to a position where the magnetic flux is sufficiently small, the coil with non-integer turns can magnetically obtain an interlinkage flux proportional to the non-integer turns. Next, a method of determining lead wire extraction positions of a plurality of partial coils will be explained. FIG. 8 is an explanatory diagram showing the approximate shape of the magnetic flux distribution of the spiral coil, and FIG. 9 is an explanatory diagram showing the distribution of interlinkage magnetic flux of each turn coil. In FIG. 8, the magnetic flux lines 50 generated by the spiral coil 3 pass through the spiral coil in the axial direction, and are arranged so that the distribution of magnetic flux lines is the densest between the center of the coil and the free surface of the molten metal 2. to be distributed. FIG. 9 is a bar graph representing the magnetic flux linkage for each turn of the spiral coil.

That is, there is a position where the maximum value is reached at the middle turn of the coil, but at the innermost and outermost turns, the value of i is small, resulting in a convex distribution. In order to set the number of partial coils to three and the number of parallel conductors to three, divide this mountain-shaped area equally into three.
This position may be used as the pull-out position of the lead. That is, in FIG. 9, the mountain-shaped area is divided into three equal parts by a point M on the turn coil 104 and a point N on the turn coil 107. The point M is therefore the angle 1 of the turn coil 104.
The angle between the 80 degree point M and the turn coil 107 (7/10
) All you have to do is pull out each lead from point N at -360 degrees. The flux linkage distribution shown in FIG. 9 can be easily and accurately calculated by calculating the magnetic field axis using a computer.

As shown in Figure 5, the leads of different partial coils are drawn out adjacently, and current flows in the opposite direction in each lead, so in order to further improve magnetic balance by utilizing this configuration, , it is possible to easily adopt a configuration in which these two leads pass through one current balancing reactor 31, 32, 33. If the magnetic flux distribution changes due to peripheral configurations other than the coils, it is possible to compensate for deviations in magnetic balance and maintain current balance in each coil.

As explained above, the effect of this invention is that a pair of lead wires arranged in close proximity and parallel to each other, through which currents of the same magnitude and in opposite directions flow, can be connected to different partial coils installed adjacently. By configuring the lead wire with the start end lead and the end lead, the lead wire can be drawn out at any position on the circumference. Next, by configuring the drawing direction of the pair of reciprocating lead wires to be restricted to the axial direction or the normal direction, the magnetic flux linkage of the non-integer turn coil of less than 1 turn can be made proportional to the number of turns. was completed.

Further, by configuring the spiral coil so that the total number of turns is an integral number of turns, the starting and ending ends of the innermost turn and the outermost turn could be located on one normal line. Furthermore, by combining the above three configurations, it is possible to configure the partial coils as coils with non-integer turns, and the number of partial coils or parallel conductors can be set to any number. In addition, by determining the number of turns of each partial coil or the drawing position of a pair of lead wires so that the interlinkage magnetic flux of each partial coil is equal to each other, it is possible to flow the same amount of current through each partial coil. It was possible to provide a spiral coil for large currents having an arbitrary number of multi-parallel conductors.

Although the above description has been made regarding a spiral coil used for induction heating of molten metal, the spiral coil of the present invention can be widely used in electrical devices using a large current spiral coil having multiple parallel conductors.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the state in which a spiral coil is used, Figures 2 and 3 are schematic structural diagrams of a conventional spiral coil, Figure 4 is an explanatory diagram of a transposed part of a conductor, and Figure 5 is a diagram of a conventional spiral coil. A structural diagram of a spiral coil showing an embodiment of the invention, FIG. 6 is a structural diagram of a lead wire extraction part, FIG. 7 is an explanatory diagram of magnetic flux linkage of a non-integer turn coil, and FIG. 8 is a diagram of the spiral coil of FIG. 1. magnetic flux distribution diagram,
FIG. 9 is a graph showing the flux linkage distribution of each turn coil. In the figure, 3... spiral coil, 4, 5, 6, 8°9
．． 10...Partial coil (integer turns), 4a, 5a
. 6a, --- Reciprocating lead wire, 7, 30a, 30b...
Bus bar, 1-1a, 1 lb-...Lead wire, 21,
22, 23. ,, partial coil (non-integer turns), 24~
29... Lead wire, 31.32, 33... Current balancing reactor, 101-110... Turn coil number,
41, 42, 45, 46 conductors. 1'1 Illustration S Figure/-/
1″r7 lower 8 Figure ter〉coil) around the beginning q concave

Claims (1)

[Claims] 1) A plurality of partial coils are formed by winding a conductor that conducts current in a disk shape through an insulating material between the eyebrows, and the partial coils are sequentially wound in contact with the outer peripheral surface of the coil to form a plurality of partial coils, and the partial coils are connected in parallel with each other. A large current coil consisting of a coil in which each partial coil is wound with a non-integer number of turns, the sum of the total number of turns being an integral number of turns, and the terminal end of one adjacent partial coil and the other end. The starting ends of the partial coils are drawn out from close positions on the same circumference by a pair of lead wires, and the starting ends of the innermost partial coils and the terminal ends of the outermost partial coils are arranged on one normal line, forming a pair. The pair of lead wires are drawn out in the axial direction or normal direction in parallel and close to each other,
A spiral coil characterized by each pair of lead wires being connected in parallel to each other.