JP2015032814A - Three-phase electromagnetic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide three-phase electromagnetic equipment which simplifies a magnetic circuit structure and a winding structure of a coil, reduces the number of coils and is easily assembled and in which a space factor of coils is enlarged and a loss is reduced.SOLUTION: A main coil and a control coil are wound around each of linear magnetic cores of a six-leg magnetic core, two main coils are paired to prepare three pairs of main coils (1aa and 1ab, 1ba and 1bb, and 1ca and 1cb), and the mail coils of each pair are connected in series or in parallel correspondingly to each phase of a three-phase AC power source. The control coils (2a, 2d, 2c, 2f, 2e and 2b) are connected in series or in parallel so as to cancel an induction voltage caused by a main magnetic flux generated by three pairs of mail coils, and a control circuit 4 is connected at an open terminal side of the control coils. A DC control magnetic flux is generated by supplying a DC control current from the control circuit 4 to the control coils, and magnetic resistance of a common magnetic path for the main magnetic flux and the DC control magnetic flux is controlled, thereby continuously varying reactance of the main coils.

Description

  The present invention relates to an electromagnetic device capable of varying the reactance of a three-phase type, and more particularly to a three-phase electromagnetic device having a large winding space factor and a simple winding structure.

  As conventional techniques capable of varying the reactance of a three-phase type corresponding to a three-phase AC power source, there are a three-phase type electromagnetic device (Patent Document 1) and a three-phase electromagnetic device (Patent Document 2) previously proposed by the present applicant.

  FIG. 11 is a connection diagram for explaining an example of the three-phase electromagnetic device (Patent Document 1) previously proposed by the present applicant. In this three-phase electromagnetic device, six linear magnetic cores 43aa to 43cb are arranged so that the angle between adjacent linear magnetic cores is 60 °, and six iron core window portions are formed at one end of the six linear magnetic cores. In this way, they are connected by a connecting magnetic core 43d.

  Three pairs of main windings 41aa to 41cb are wound around the six linear magnetic cores 43aa to 43cb, and are connected in series or in parallel so that the magnetic flux generated from each pair of main windings is in the same direction. The six connecting magnetic cores 43d connected with the linear magnetic cores are respectively wound with control windings 42a to 42f, and a direct current control current Ic is caused to flow through the control windings. The magnetic resistance of the path is controlled, and the reactance of the main winding is continuously varied.

  FIG. 12 is a connection diagram for explaining an example of the three-phase electromagnetic device (Patent Document 2) previously proposed by the present applicant. In this three-phase electromagnetic device, 18 linear magnetic cores 53aa to 53dL are arranged radially, and further, 18 core windows are arranged at the center side (inner side) end and the peripheral side (outer side) end of the 18 linear magnetic cores. The magnetic cores 53e and 53f are connected so as to form a portion.

  Then, sixteen AC main windings 51aa to 51cb are mounted on every other 18 legs on 18 linear magnetic cores, and DC control windings 52a to 52L are wound around the other 12 legs, respectively. By flowing the DC control current Ic through the wire, the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux is controlled, and the reactance of the main winding is continuously variable.

Japanese Patent No. 4646327 JP 2013-042028 A

  However, although the three-phase electromagnetic device of Patent Document 1 can control the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux and continuously vary the reactance of the main winding, Since three main windings or control windings are wound around the window, the space factor of the windings is lowered. Further, since it is necessary to wind the control winding around the connecting magnetic core, it is necessary to perform manual winding after forming the magnetic core.

  Furthermore, the common magnetic path of the main magnetic flux and the control magnetic flux for varying the reactance is mainly the magnetic path around the window around which the control winding is wound, and since the adjustment range of the magnetic resistance is narrow, the variable range of the reactance is also Not wide.

  The three-phase electromagnetic device of Patent Document 2 has been proposed in view of the problems of the three-phase electromagnetic device of Patent Document 1, and has a configuration that does not require the control winding to be wound around the coupling core. It is possible to continuously vary the reactance of the winding.

  However, the three-phase electromagnetic device requires 18 linear magnetic cores, and when the iron core window is enlarged in accordance with the capacity, the diameter of the connecting magnetic core on the peripheral side (outer side) and the central side (inner side) is large. Therefore, the whole magnetic core tends to be large and the weight tends to be heavy. Furthermore, since 12 control windings are required for 6 main windings, the number of equipment assembly steps increases and the winding weight also increases.

  Similarly to the three-phase electromagnetic device of Patent Document 1, the three-phase electromagnetic device of Patent Document 2 has a common magnetic path for main reactance and control magnetic flux for varying the reactance. This is a magnetic path in the peripheral part, and since the adjustment range of the magnetic resistance is narrow, the variable range of reactance is not wide.

  In addition, the three-phase electromagnetic device of Patent Document 1 and the three-phase electromagnetic device of Patent Document 2 are required to separate and wind the main winding and the control winding, so that space reduction and assembly are easy. There is a problem that it is difficult to apply the lap winding of the general-purpose technology.

  The present invention has been made in view of these circumstances, and is a three-phase electromagnetic device capable of varying a reactance over a wide range without using a gap on the abutting surface of the iron core without using a tap. It is an object of the present invention to provide a three-phase electromagnetic device having a simple winding structure, a small number of windings, simple assembly, a large winding space factor, and a low loss.

  According to the present invention, in reducing the number of 12 control windings wound around 18 linear magnetic cores shown in Patent Document 2, conventionally, the superposition of DC magnetic flux which causes an increase in current distortion of the AC windings. Focusing on the winding of the AC winding and the control winding around the same linear magnetic core, which was said to be difficult to prevent demagnetization due to the same, by setting the appropriate winding direction on the control winding, it is the same This is because it has been found that no demagnetization occurs between the AC terminals of the phases. Furthermore, it is because the control magnetic flux is returned to the entire magnetic path by winding the AC winding and the control winding around the same linear magnetic core, and the reactance can be varied over a wide range.

  In order to solve the above-mentioned problems, the first technical means of the present invention has six linear magnetic cores connected at the center side and arranged radially symmetrically, and the peripheral ends of the respective linear magnetic cores are connected by the connecting magnetic cores. A three-phase electromagnetic device having a six-leg magnetic core, in which a main winding and a control winding are wound around each of the linear magnetic cores, and two main windings are used as one pair to form three main windings. A main winding is connected in series or in parallel corresponding to each phase of the three-phase AC power supply, and the control winding is connected in series or in parallel so as to cancel the induced voltage caused by the main magnetic flux generated by the three pairs of main windings. And connecting a control circuit to the open terminal side of the control winding and supplying a DC control current from the control circuit to the control winding to generate a DC control flux, and the main flux and the DC control flux Control the reluctance of the main winding by controlling the reluctance of the common magnetic path It is characterized by varying the.

A second technical means is characterized in that, in the first technical means, the linear magnetic cores wound with the pair of main windings are two linear magnetic cores located on the same axis.
The third technical means is characterized in that, in the first technical means, the linear magnetic cores wound with the pair of main windings are two adjacent linear magnetic cores.

  The fourth technical means is the second or third technical means, so that the direction of the magnetic flux generated from the two main windings as the pair of main windings is the same direction toward the center side. The pair of main windings are connected in series or in parallel.

  A fifth technical means is characterized in that in any one of the first to fourth technical means, a secondary winding is additionally arranged on a linear magnetic core wound with a main winding and a control winding of each phase. .

  According to the present invention, a three-phase electromagnetic device capable of varying a reactance over a wide range without using a gap on the abutting surface of the iron core without using a tap, the magnetic circuit structure and the winding structure of the winding are simple, It is possible to realize a three-phase electromagnetic device with a small number of windings, easy assembly, a large winding space factor and low loss.

  Further, by using the present invention for an electric power system, it is possible to cope with a recent increase in electric power demand and a fluctuation in the electric power system voltage due to diversification of loads, and to provide a flexible electric power facility. This can contribute to voltage stabilization and more appropriate control of power factor and power flow.

It is a figure which shows the basic structural example of the three-phase electromagnetic device by this invention. It is a figure which shows the equivalent circuit of the three-phase electromagnetic device of this invention. It is a figure for demonstrating the structure of the magnetic core of the three-phase electromagnetic device by this invention, and the connection of a coil | winding. It is a figure which shows the example of a magnetic core assembly of the three-phase electromagnetic device by this invention. It is a figure which shows the example of a magnetic core structure of the three-phase electromagnetic device by this invention. It is a figure which shows the example of a coil | winding structure of the three-phase electromagnetic device by this invention. It is a figure for demonstrating the example of control magnetic flux of the three-phase electromagnetic equipment by this invention. It is a figure which shows the control characteristic example of the three-phase electromagnetic equipment of this invention. It is a figure which shows the example of the three-phase electromagnetic device which has a transformation function by this invention. It is a figure which shows the example of application to the reactive power compensation apparatus of this invention. It is a figure which shows the example of the conventional three-phase electromagnetic device. It is a figure which shows the other example of the conventional three-phase electromagnetic device.

  Hereinafter, preferred embodiments of the three-phase electromagnetic device of the present invention will be described with reference to the drawings. In the following description, the configurations denoted by the same reference numerals in different drawings are the same, and the description thereof may be omitted.

  FIG. 1 is a diagram showing a basic configuration example of a magnetic core and windings of a three-phase electromagnetic device according to the present invention, FIG. 2 is a diagram showing a circuit configuration in which the three-phase electromagnetic device of the present invention is equivalently displayed, and FIG. These are the figures for demonstrating the structure of the magnetic core of 3 phase electromagnetic equipment shown in FIG. 1, and the connection of a coil | winding.

  As shown in FIG. 3, the magnetic cores constituting the three-phase electromagnetic device are joined together by gathering one end (center side) of each of the six linear magnetic cores 3aa, 3ab, 3ba, 3bb, 3ca and 3cb. The six legs are formed so that the angle formed by the magnetic core is 60 °. Further, a six-leg magnetic core is configured in which the other end (peripheral end) of the linear magnetic core forming the six legs is connected by a connecting magnetic core 3d serving as an annular yoke so that six iron core window portions are formed. ing. In addition, each joint part of the linear magnetic cores 3aa, 3ab, 3ba, 3bb, 3ca and 3cb and the joint part with the connecting magnetic core 3d may be configured by abutting each laminated steel plate constituting the magnetic core so as to be parallel to each other. it can.

  An AC main winding (hereinafter referred to as “main winding”) and a DC control winding (hereinafter referred to as “control winding”) are wound around each of the six linear magnetic cores. Specifically, the main winding 1aa and the control winding 2a are provided in the first linear magnetic core 3aa, and the main winding 1ab is provided in the second linear magnetic core 3ab disposed on the same axis as the first linear magnetic core 3aa. And the control winding 2d is wound. Here, the main windings 1aa and 1ab correspond to one phase of the three-phase AC power supply as a pair of main windings, and the magnetic fluxes φa1 and φa2 generated from both main windings face each other in the central direction. That is, they are connected in series or in parallel so as to be in the same direction toward the center side.

  Similarly, the main winding 1ba and the control winding 2c are provided in the third linear magnetic core 3ba, and the main winding 1bb and the control winding are provided in the fourth linear magnetic core 3bb disposed on the same axis as the third linear magnetic core 3ba. The winding 2f is wound, and the main windings 1ba and 1bb are connected in series or in parallel so that the magnetic fluxes φb1 and φb2 generated from both main windings face each other in the central direction.

  The fifth linear magnetic core 3ca has a main winding 1ca and a control winding 2e. The sixth linear magnetic core 3cb arranged on the same axis as the fifth linear magnetic core 3ca has a main winding 1cb and a control winding. The wire 2b is wound, and the main windings 1ca and 1cb are connected in series or in parallel so that the magnetic fluxes φc1 and φc2 generated from both main windings face each other in the central direction.

  Six control windings 2a, 2d, 2c, 2f, 2e, and 2b wound around the linear magnetic cores 3aa, 3ab, 3ba, 3bb, 3ca, and 3cb include main windings 1aa and 1ab, main windings 1ba and 1bb, and It is connected in series or in parallel so that the voltages induced in the control windings 2a, 2d, 2c, 2f, 2e and 2b by the magnetic fluxes of the main windings 1ca and 1cb cancel each other, and the control circuit 4 is provided on the open terminal side. Connecting.

  In the example of FIG. 3, the control windings 2a, 2c, and 2e generate a magnetic flux toward the center side of the linear magnetic core when a current flowing in the same direction as the control DC current Ic is induced. The lines 2b, 2d and 2f are connected in series so as to generate a magnetic flux toward the peripheral end of the linear magnetic core when a current flowing in the same direction as the control DC current Ic is induced.

  For example, the voltage induced in the control winding 2a wound around the same linear magnetic core 3aa by the change of the magnetic flux φa1 generated by the current flowing in the main winding 1aa of the first linear magnetic core 3aa and the main of the second linear magnetic core 3ab The control windings 2a and 2d are connected in series so that the voltage induced in the control winding 2d is canceled by the change in the magnetic flux φa2 generated by the current flowing through the winding 1ab. Similarly, the voltages induced in the control windings 2b and 2e and the control windings 2c and 2f are connected in series so as to cancel each other. Since the balanced three-phase alternating current flows through the main winding, the induced voltages of the control windings cancel each other.

  Therefore, as shown in FIG. 3, it is possible to connect all the control windings in series, or connect the control windings 2a and 2d, 2b and 2e, 2c and 2f in series, respectively. The connected ones can also be connected in series and parallel.

In FIG. 3, it is assumed that a three-phase AC power source is connected to an open terminal of a main winding that is wound and connected to a linear magnetic core, and currents ILu, ILv, and ILw in the directions indicated by the arrows flow through the main windings. . When the current arrow direction is a positive cycle, a reverse current flows in the negative cycle.
In the three-phase electromagnetic device having the above configuration, when no DC control current is supplied to the control winding, each of the phases generated from the main windings 1aa and 1ab, the main windings 1ba and 1bb, and the main windings 1ca and 1cb. The AC magnetic flux returns through a connecting magnetic core that connects linear magnetic cores.

Hereinafter, the description will be given focusing on the first linear magnetic core 3aa wound with the main winding 1aa and the second linear magnetic core 3ab wound with the main winding 1ab.
When current ILu flows, main magnetic flux φa1 and main magnetic flux φa2 are generated in the magnetic path by main winding 1aa and main winding 1ab, respectively. The generated main magnetic flux passes through another linear magnetic path portion and the connecting magnetic core 3d when no DC control current is passed through the control winding, and the main winding has a reactance according to the number of turns and the magnetic resistance of the magnetic core. Arise. Here, the linear magnetic core and the connecting magnetic core serve as a common magnetic path for the control magnetic flux φdc and the main magnetic fluxes φa1 and φa2.

  The above is the case where attention is paid to the third linear magnetic core 3ba around which the main winding 1ba is wound and the fourth linear magnetic core 3bb around which the main winding 1bb is wound, and the case where the main winding 1ca is wound. The same applies to the case where attention is paid to the fifth linear magnetic core 3ca and the sixth linear magnetic core 3cb around which the main winding 1cb is wound.

  When the DC control current Ic is supplied to the control winding while the main winding current ILu is supplied, in the control windings 2a, 2b, 2c, 2d, 2e and 2f, the product of the number of turns of the control winding and the control current Ic When the magnetomotive force expressed is generated, the magnetic flux density of the common magnetic path portion in which the control winding magnetic flux φdc and the main magnetic fluxes φa1 and φa2 are in the same direction increases, and the permeability changes, and the main magnetic flux is controlled. Reactance decreases.

  Since this holds true for other linear magnetic cores, it is possible to operate as a three-phase electromagnetic device whose reactance can be varied by adjusting the DC control current Ic.

  As described above, in the magnetic circuit configuration of the present invention, the common magnetic path of the main magnetic flux and the control magnetic flux for changing the permeability, controlling the main magnetic flux, and changing the reactance is each linear magnetic core and the connecting magnetic core. As will be described later, the reactance can be varied over a wide range as compared with the conventional structure by changing the magnetic resistance of the magnetic path over a wide range.

  FIG. 4 shows an example of assembling a magnetic core of a three-phase electromagnetic device according to the present invention. After the main winding 1 and the control winding 2 are inserted into a linear magnetic core 3 constructed with a stacked core structure, the outer coupling is shown. The magnetic core 3 is assembled and configured, the assembly is simple, the space factor of the winding is improved, and the weight of the electromagnetic device can be reduced. Here, the main winding 1 and the control winding 2 can be of an integral structure with lap winding.

  FIG. 5 shows an example of a magnetic core configuration of a three-phase electromagnetic device according to the present invention. FIG. 5A shows a case where the connecting magnetic cores connecting the linear magnetic cores form a circular shape as described above. Can be easily constructed from the punched iron core used in FIG. 5B omits the central hole shape connecting the linear magnetic cores, and can be simply configured from a punched iron core used in an electric motor or the like as described above.

  5 (C) and 5 (D), the shape of the connecting magnetic cores connecting the linear magnetic cores is a straight line, and can be easily configured with a stacked iron core in addition to the punched iron core. Note that the connecting magnetic cores can be formed in various shapes as long as the six connecting magnetic cores have the same configuration. 5 (E) and 5 (F), the connecting portion of the linear magnetic cores in the central portion of the magnetic core is a connecting magnetic core, and the window shape around which the winding is wound has a trapezoidal shape, and is simply configured with an iron core. In addition, the space factor of the winding can be improved, and the weight of the electromagnetic device can be reduced.

  FIG. 6 shows an example of the winding configuration of the three-phase electromagnetic device according to the present invention. FIG. 6 (A) shows an example in which the main winding and the control winding are configured as separate windings, and FIG. 6 (B) shows the main winding. This is an example in which the winding and the control winding are configured as a lap winding. In the three-phase electromagnetic device according to the present invention, the winding configuration can be overlapped as shown in FIG. 6B, and the separated winding that is essential in the conventional winding configuration shown in FIGS. Compared with the case of wearing, the winding configuration can be greatly simplified.

  FIG. 7 shows an example of the magnetic flux density of the control magnetic flux and the magnetic path when a control current is passed in a three-phase electromagnetic device. FIG. 7A shows an example of the case of the control winding arrangement of the present invention. FIG. 7B shows an example in the case of the conventional control winding arrangement shown in FIG. In FIG. 7, the portion where the magnetic flux density is large is painted darkly.

  In the conventional control winding arrangement, since the control winding is wound around the outer connecting magnetic core, the control magnetic flux only circulates through the connecting magnetic core, and the region where the magnetic flux density becomes large is limited only to the connecting magnetic core. . On the other hand, by adopting the control winding arrangement of the present invention, the control magnetic flux circulates in the entire magnetic core portion, and the region where the magnetic flux density is large is all of the linear magnetic core and the connecting magnetic core. Compared with the above, the reactance can be varied over a wide range.

  FIG. 8 shows an example of control characteristics when a three-phase AC voltage is applied to the three-phase electromagnetic device according to the present invention to increase the DC control current Ic. FIG. 8A shows an example of control characteristics of the main winding current, and it can be seen that the reactance changes and the main winding current can be varied linearly by increasing the DC control current Ic. FIG. 8B shows a current distortion characteristic example of the main winding current, and it can be seen that the main winding current distortion is good regardless of the DC control current Ic. In addition, the above control characteristics have no unbalance between the three phases, and are consistent within the measurement error range.

  As described above, according to the present invention, the reactance of each of the three phases can be varied at high speed and continuously by adjusting the DC control current.

  FIG. 9 is a diagram showing an example of a three-phase electromagnetic device having a transformer function according to the present invention. In the configuration of the magnetic core winding shown in FIG. 1, the main winding constituting the electromagnetic device is a primary winding, and the secondary winding 6aa and the primary winding 5ab are wound around a linear magnetic core wound with the primary winding 5aa. The secondary winding 6ab and the primary winding 5ba are wound around the straight magnetic core, the secondary winding 6ba is wound around the linear magnetic core wound around the primary winding 5bb, and the secondary winding 6bb and the primary winding 5ca are wound around the linear magnetic core wound around the primary winding 5bb. The secondary winding 6ca and the primary winding 5cb are wound around the rotated linear magnetic core, the secondary winding 6cb is wound around the linear magnetic core, and these secondary windings are connected in the same manner as the primary winding. Thus, a three-phase electromagnetic device having a transformation function can be realized.

In FIG. 9, it is assumed that a three-phase AC power source is connected to the primary winding and a three-phase load is connected to the secondary winding, and currents ILu2, ILv2, and ILw2 in the directions indicated by the arrows flow through the respective secondary windings. .
Hereinafter, the first linear magnetic core wound with the primary winding 5aa and the second linear magnetic core wound with the primary winding 5ab will be described.

  When the control current is not passed, the primary currents ILu1 flow in the primary windings 5aa and 5ab so as to cancel the magnetic flux generated by the secondary current, and the primary windings 5aa and 5ab and the secondary windings 6aa and The same applies when attention is paid to the primary windings 5ba and 5bb and the secondary windings 6ba and 6bb, the primary windings 5ca and 5cb, and the secondary windings 6ca and 6cb. As a whole, it functions as a transformer.

  When a DC control current Ic is passed through the control winding, a magnetic force is generated by generating a magnetomotive force represented by the product of the number of turns of the control winding and the control current Ic, thereby controlling the main magnetic flux. For this reason, the excitation current for generating the main magnetic flux required to maintain the voltage between the terminals of the primary winding increases in accordance with the decrease of the main magnetic flux accompanying the control of the control current.

  That is, in addition to the transformer function as a transformer, the reactive current of the main winding can be continuously varied by adjusting the control current, and the delay reactive current flowing into the primary side can be adjusted. Since this holds true for other linear magnetic cores as well, in addition to the transformer function as a transformer, it can function as a three-phase electromagnetic device whose reactance can be varied.

(Application example)
FIG. 10 is an equivalent circuit showing an application example of the present invention to a reactive power compensator for a three-phase electromagnetic device.
In FIG. 10, a three-phase electromagnetic device according to the present invention is three-phase connected, and a power capacitor 7 connected in parallel is inserted in parallel to the transmission line, and the phase is advanced from the slow phase generated in the system by controlling the electromagnetic device. The reactive power is continuously compensated.

  As described above in detail, according to the present invention, since it is not necessary to wind the control winding around the connecting magnetic core without providing a tap, the assembly is simple and no gap is required on the abutting surface of the iron core. It is possible to realize a three-phase electromagnetic device with variable reactance over a wide range. In addition, due to the recent increase in power demand and diversification of loads, flexible power facilities that can cope with diversification of loads such as fluctuations in system voltage have been provided. Can contribute to appropriate control.

  In the above embodiment, the case where the linear magnetic cores wound with a pair of main windings, for example, 1aa and 1ab are two linear magnetic cores 3aa and 3ab located on the same axis has been described. Various modifications can be made without departing from the scope of the invention.

  For example, a pair of main windings may be wound around two adjacent linear magnetic cores. In this case, the direction of magnetic flux generated from each main winding of the pair of main windings is directed toward the center side. What is necessary is just to connect in series or parallel so that it may become the same direction. The two control windings wound around the same linear core as the pair of main windings are connected so as to cancel the induced voltage caused by the change in the main magnetic flux caused by the change in the current flowing through the pair of main windings. Just keep it.

1 (1aa, 1ab, 1ba, 1bb, 1ca, 1cb) ... main winding, 2 (2a, 2b, 2c, 2d, 2e, 2f) ... control winding, 3 (3aa, 3ab, 3ba, 3bb, 3ca, 3cb, 3d) ... magnetic core, φa1, φa2, φb1, φb2, φc1, φc2 ... main magnetic flux, φdc ... control magnetic flux, 4 ... control circuit, 5 (5aa, 5ab, 5ba, 5bb, 5ca, 5cb) ... primary winding , 6 (6aa, 6ab, 6ba, 6bb, 6ca, 6cb) ... secondary winding, 7 ... power capacitor.

Claims (5)

A three-phase electromagnetic device having six linear magnetic cores connected at the center side and arranged radially symmetrically, and having a six-legged magnetic core in which peripheral ends of the linear magnetic cores are connected by a connecting magnetic core,
The main winding and the control winding are wound around each of the linear magnetic cores, the two main windings are paired into three main windings, and each pair of main windings corresponds to each phase of the three-phase AC power source. Connected in series or in parallel,
Connecting the control winding in series or in parallel so as to cancel the induced voltage caused by the main magnetic flux generated by the three pairs of main windings, and connecting a control circuit to the open terminal side of the control winding;
A DC control magnetic flux is generated by supplying a DC control current from the control circuit to the control winding, and a magnetic resistance of a common magnetic path of the main magnetic flux and the DC control magnetic flux is controlled to continuously react the reactance of the main winding. Three-phase electromagnetic equipment characterized by being variable.   The three-phase electromagnetic device according to claim 1, wherein the linear magnetic core around which the pair of main windings are wound is the two linear magnetic cores located on the same axis.   The three-phase electromagnetic device according to claim 1, wherein the linear magnetic core around which the pair of main windings are wound is the two adjacent linear magnetic cores.   The pair of main windings are connected in series or in parallel so that the direction of magnetic flux generated from the two main windings serving as the pair of main windings is the same direction toward the center. The three-phase electromagnetic device according to claim 2 or 3.   The three-phase electromagnetic device according to any one of claims 1 to 4, wherein a secondary winding is additionally arranged on a linear magnetic core wound with a main winding and a control winding of each phase. Electromagnetic equipment.

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