3 phase ac wire

Abstract

To provide a 3 phase AC wire in which reduction of inductance is attained.SOLUTION: A conductor of one of the u-phase, v-phase, or w-phase is a tubular conductor with an annular cross-section perpendicular to its length direction, and the conductors of the other two phases are either both arranged inside the tubular conductor or both arranged outside the tubular conductor, with each conductor carrying each phase being arranged to face the conductors carrying the other two phases, thereby providing a three-phase AC power line.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a three-phase AC electric wire through which three-phase AC current is passed. [Background technology]

[0002] Conventionally, known AC electric wires include single-phase two-wire electric wires and three-phase three-wire electric wires. In three-phase AC electric wires, current is passed through each phase, referred to as u-phase, v-phase, w-phase, A-phase, B-phase, C-phase, etc., with a phase difference of 120 degrees. Therefore, in three-phase AC, even when transmitting the same power as single-phase AC, the current value flowing through the conductor can be lower than that of single-phase AC, thereby reducing electrical loss. When AC current flows through an electric wire, factors such as inductance, reactance, and impedance are known to affect loss. Patent Document 1 listed below discloses a technique for reducing impedance by dividing the conductors of each phase in a three-phase AC electric wire into multiple strips and arranging them so that the same phase strips are not adjacent to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication No. 49-41269 Summary of the Invention [Problem to be solved by the invention]

[0004] Among the factors that affect electrical loss in three-phase AC electric wires, inductance is desired to be reduced because it can cause voltage fluctuations and, in some cases, can generate high voltages known as surge voltages. However, to date, no sufficient measures have been established to reduce inductance in three-phase AC electric wires. Therefore, an object of the present invention is to provide a three-phase AC electric wire with reduced inductance. [Means for solving the problem]

[0005] As a result of intensive research into solving the above problem, it was found that the above problem can be solved by making the conductor that carries one of the three phases (for example, the w phase) cylindrical, and arranging the conductors that carry the remaining two phases (for example, the u phase and the v phase) inside the cylindrical conductor that carries the w phase, or by arranging both outside the cylindrical conductor that carries the w phase, and further arranging the conductors that carry each phase so that they face the conductors that carry the other two phases, which led to the completion of the present invention.

[0006] That is, in order to solve the above problems, the present invention provides: A three-phase AC electric wire having conductors through which the u-phase, v-phase, and w-phase of three-phase AC flow, having a length direction, The conductor of one of the u-phase, v-phase, and w-phase is a cylindrical conductor having a circular cross section perpendicular to the longitudinal direction, The conductors of the other two phases are: Either both are disposed inside the cylindrical conductor, or both are disposed outside the cylindrical conductor, The conductors through which the phases flow are: and a three-phase AC electric wire arranged to face the conductor through which two phases other than the conductor flow. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the inductance in a three-phase AC electric wire. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing a three-phase AC electric wire according to one embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the structure of a wire body of a three-phase AC wire. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the structure of a wire body of a three-phase AC wire. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the structure of a three-phase AC electric wire according to another embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing the structure of a three-phase AC electric wire according to another embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view showing the structure of a three-phase AC electric wire according to another embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing the structure of a three-phase AC electric wire according to another embodiment. [Figure 8] FIG. 8 is an explanatory diagram showing a simulation model of the three-phase AC electric wires of Comparative Examples 1 to 3 and Examples 1 to 4. [Figure 9] FIG. 9 is an explanatory diagram showing the simulation results of the three-phase AC electric wires of Comparative Examples 1 to 3 and Examples 1 to 4. [Figure 10] FIG. 10 is an explanatory diagram showing the simulation models of the three-phase AC electric wires of Comparative Example 4 and Example 5 and the simulation results. [Figure 11] FIG. 11 is an explanatory diagram showing simulation models of three-phase AC electric wires of Examples 4 and 5 and Comparative Example 5 and the simulation results. [Figure 12] FIG. 11 is an explanatory diagram showing simulation models of three-phase AC electric wires of Comparative Example 6 and Example 6 and the simulation results. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will be described below with reference to the drawings. A three-phase AC electric wire 1 shown in FIG. 1 is used to carry AC current of three phases, u-phase, v-phase, and w-phase, which are 120 degrees out of phase with each other. The three-phase AC electric wire 1 of this embodiment includes a wire main body 10 including a conductor and an insulator covering the conductor, and a sheath portion 20 that covers the wire main body 10. The three-phase AC electric wire 1 shown in FIG. 1 is a flat wire, and has a length direction DL that is parallel to the direction of extension along a central axis CAX.

[0010] The three-phase AC electric wire 1 of this embodiment has a cross-sectional shape of a horizontally long rectangle when cut along an imaginary plane VP perpendicular to the longitudinal direction DL. The flat wire may have a cross-sectional shape of a horizontally long oval. When the cross-sectional shape of the flat wire is an oval, the cross-sectional shape may be a rectangle with two short sides formed in a semicircular arc shape, or an elliptical cross-sectional shape. The three-phase AC electric wire 1 of this embodiment has a major axis direction DW parallel to the long sides of the rectangle or the major axis of the oval, and a minor axis direction DT parallel to the short sides of the rectangle or the minor axis of the oval.

[0011] 2 shows the cross-sectional shape of the wire main body 10 of the three-phase AC wire 1 of this embodiment, which is a flat wire having a horizontally elongated rectangular cross-sectional shape. As shown in the figure, the left-right direction in the figure is the long diameter direction of the three-phase AC wire 1 of this embodiment, which will hereinafter also be referred to as the width direction. Also, in FIG. 2, the up-down direction is the short diameter direction, which will hereinafter also be referred to as the thickness direction. Furthermore, the three-phase AC wire 1 of this embodiment has a circumferential direction DR, which is the direction of winding around the central axis CAX.

[0012] The three-phase AC electric wire 1 illustrated in the figures has three conductors for carrying current in the u-phase, v-phase, and w-phase in a wire main body 10. One of the three conductors is a cylindrical conductor CT that is cylindrical and extends in the longitudinal direction DL, and the other is a strip-shaped conductor CB that is long and extends in the longitudinal direction DL. The wire main body 10 is provided with two strip-shaped conductors CB: a first strip-shaped conductor CB1 and a second strip-shaped conductor CB2.

[0013] The tubular conductor CT has a rectangular cross-sectional shape that is slightly smaller than the three-phase AC wire 1, and extends in the longitudinal direction DL in the shape of a rectangular tube. The tubular conductor CT in this embodiment is disposed in the outermost layer of the wire main body 10, and its outer peripheral surface forms the outer peripheral surface of the wire main body 10. The wire main body 10 in this embodiment may have an insulating layer on the outside of the tubular conductor CT.

[0014] For the reasons described above, the tubular conductor CT in this embodiment has a smaller diameter than the three-phase AC electric wire 1 by the thickness of the sheath portion 20, and the dimension LWO in the width direction (long diameter direction DW) is larger than the dimension LTO in the thickness direction (short diameter direction DT). Furthermore, the tubular conductor CT has an inner dimension LWI in the long diameter direction DW (the distance between the inner circumferential surfaces of the tubular conductor CT in the long diameter direction DW = LWO - 2 × t0) obtained by subtracting the thickness t0 of the tubular conductor CT from the dimension LWO in the long diameter direction DW, which is also longer than the inner dimension LTI in the short diameter direction DT (the distance between the inner circumferential surfaces of the tubular conductor CT in the short diameter direction DT = LTO - 2 × t0) obtained by subtracting the dimension (2 × t0) corresponding to the thickness of the tubular conductor CT from the dimension LTO in the short diameter direction DT.

[0015] The first band-shaped conductor CB1 and the second band-shaped conductor CB2 are arranged inside the tubular conductor CT so that their width direction is along the major axis direction DW of the three-phase AC electric wire 1. The width LC1 of the first band-shaped conductor CB1 and the width LC2 of the second band-shaped conductor CB2 are shorter than the inner dimension LWI of the tubular conductor CT in the major axis direction DW, and they are arranged at a distance from the tubular conductor CT so as not to contact the tubular conductor CT at both ends in the major axis direction DW. The first band-shaped conductor CB1 and the second band-shaped conductor CB2 have linear cross-sectional shapes on the imaginary plane VP perpendicular to the central axis CAX, and are arranged inside the tubular conductor CT so that the extending direction of the linear cross-section is parallel to the major axis direction DW.

[0016] The sum of the thickness t1 (dimension in the short diameter direction DT) of the first strip conductor CB1 and the thickness t2 (dimension in the short diameter direction DT) of the second strip conductor CB2 is shorter than the internal dimension LTI of the tubular conductor CT in the short diameter direction DT. In this embodiment, the first strip conductor CB1 and the second strip conductor CB2 are arranged at a distance from each other in the short diameter direction DT, and are also arranged at a distance from each other in the short diameter direction DT with respect to the tubular conductor CT. The first strip conductor CB1 and the second strip conductor CB2 are arranged so as to be one of two parallel straight lines in the cross section.

[0017] The first strip conductor CB1 is disposed so that its upper surface faces the lower surface of the second strip conductor CB2, and its lower surface and side end surfaces face the inner circumferential surface of the tubular conductor CT. The second strip conductor CB2 is disposed so that its lower surface faces the upper surface of the first strip conductor CB1, and its upper surface and side end surfaces face the inner circumferential surface of the tubular conductor CT. The inner circumferential surface of the tubular conductor CT faces the lower surface and side end surfaces of the first strip conductor CB1 and the upper surface and side end surfaces of the second strip conductor CB2. The tubular conductor CT, the first strip conductor CB1, and the second strip conductor CB2 are assigned to carry u-phase, v-phase, and w-phase AC currents. Therefore, in the three-phase AC electric wire 1 of this embodiment, the conductors carrying each of the three phases face the conductors carrying the other two phases.

[0018] As described above, in the three-phase AC electric wire 1 of this embodiment, the first band-shaped conductor CB1 and the second band-shaped conductor CB2 are arranged inside the tubular conductor CT. However, in the internal space V inside the inner peripheral surface of the tubular conductor CT, other than the range occupied by the first band-shaped conductor CB1 and the second band-shaped conductor CB2, for example, a volume resistivity of 1×10 at normal temperature and normal humidity (for example, 23° C., 50% RH) is not included. 13 A resin composition having an electrical insulation property of Ω·cm or more can be filled in an unfoamed or foamed state. Furthermore, the area outside the area occupied by the first and second strip conductors CB1 and CB2 can be filled with, for example, kraft paper, nonwoven tape, PP yarn, jute, blended yarn, or the like, or with a resin film or insulating paper.

[0019] The three-phase AC electric wire 1 of this embodiment may be, for example, as shown in Fig. 3 , a three-phase AC electric wire 1 including two flat insulated electric wires (EW1, EW2) stacked one above the other (in the short-diameter direction DT) inside the tubular conductor CT. The first flat insulated electric wire EW1 and the second flat insulated electric wire EW2 have a width corresponding to the inner dimension LWI in the long-diameter direction DW of the tubular conductor CT and a thickness equal to or less than half the inner dimension LTI in the short-diameter direction DT of the tubular conductor CT. The first flat insulated electric wire EW1 may be formed by applying an insulating coating IS1 to a first band-shaped conductor CB1 by a common method such as tape winding or extrusion coating. Similarly, the second flat insulated electric wire EW2 may be formed by applying an insulating coating IS2 to a second band-shaped conductor CB2 by a common method such as tape winding or extrusion coating.

[0020] Although the three-phase AC electric wire 1 of this embodiment can be used to pass high-voltage AC (more than 600 V but not more than 7 kV), it is primarily used for low-voltage (600 V or less) electric current. Therefore, the internal space V of the tubular conductor CT, other than the area occupied by the first and second strip conductors CB1 and CB2, may not be filled with a resin composition, but insulation by spatial insulation may be ensured. For example, the three-phase AC electric wire 1 may be provided with spacers in the longitudinal direction DL to fix the relative positions of the tubular conductor CT, the first and second strip conductors CB1 and CB2, and the remaining space may be left empty (air) to ensure insulation by spatial insulation. Furthermore, if the tubular conductor CT is to be made airtight, it may be filled with a gas such as SF6 or with an electrical insulating oil as specified in JIS C 2320:1999.

[0021] The tubular conductor CT, the first strip conductor CB1, and the second strip conductor CB2 may be made of materials commonly used in electric wires. They may be made of multiple strands (annealed copper wires). The first strip conductor CB1 and the second strip conductor CB2 may be made of multiple twisted wires arranged in the longitudinal direction DW. The first strip conductor CB1 and the second strip conductor CB2 may be made of flat copper wire. The flat copper wire may be a thin one called a copper tape. The flat copper wire may also be a braided wire in which multiple strands are woven into a strip shape. The tubular conductor CT may also be a copper tape or braid. The tubular conductor CT may be made by rolling a copper tape having a width equal to or greater than the circumferential length of the electric wire main body 10 into a rectangular tube. The tubular conductor CT may also be formed by spirally wrapping a thin copper tape. The tubular conductor CT may also be a braided body braided into a rectangular tube. The cylindrical conductor CT may also be a corrugated tube made of metal.

[0022] The three-phase AC electric wire 1 of this embodiment may be used to carry AC current at commercial frequencies (50 Hz, 60 Hz) or high-frequency three-phase AC. When the three-phase AC electric wire 1 of this embodiment is used under shallow skin depth conditions, the first band-shaped conductor CB1 and the second band-shaped conductor CB2 may be hollow or may be flat metal tubes. Furthermore, the first band-shaped conductor CB1 and the second band-shaped conductor CB2 may be formed by forming a metal layer of metal tape or metal wire on the circumferential surface of a resin tape, and the metal layer may be, for example, a plated coating.

[0023] The three-phase AC electric wire 1 of this embodiment has the above-described configuration, which can reduce inductance. The reason for the reduction in inductance is considered to be that the conductors carrying the u-phase, v-phase, and w-phases face each other over a wide area, preventing localized effects of electric field and magnetic field fluctuations in the other phases, and that the cylindrical shape of at least one conductor makes it difficult for a locally high voltage potential to be induced from the other phases.

[0024] In the three-phase AC electric wire 1 illustrated in FIGS. 1 to 3, the cross-sectional shape of the tubular conductor CT is oval or rectangular, and has a short diameter direction DT and a long diameter direction DW. Of the three phases of AC current, conductors through which two phases of AC current other than the phase flowing through the tubular conductor CT flow are strip conductors CB arranged inside the tubular conductor CT so that the long diameter direction DW is the width direction, and the strip conductors CB are arranged inside the tubular conductor CT so as to overlap with a distance in the short diameter direction DT. However, in order to achieve the above-mentioned functions, the conductor arranged inside the tubular conductor CT may be divided, for example, as shown in FIG. 4.

[0025] In the three-phase AC electric cable 1 illustrated in Fig. 4, conductors C carrying two AC currents other than the phase flowing through the tubular conductor CT out of the three AC currents are both arranged inside the tubular conductor CT, and multiple conductors C carrying each of the two phases are provided inside the tubular conductor CT. In the three-phase AC electric cable 1 illustrated in Fig. 4, when the phase flowing through the tubular conductor CT is designated as the first phase, the other two phases are designated as the second and third phases, and the conductor carrying the second-phase AC current is designated as the second-phase conductor CX and the conductor C carrying the third-phase current is designated as the third-phase conductor CY, multiple conductors C including a first second-phase conductor CX1 and a second second-phase conductor CX2 are arranged inside the tubular conductor CT as the second-phase conductors CX, and multiple conductors C including a first third-phase conductor CY1 and a second third-phase conductor CY2 are arranged inside the tubular conductor CT as the third-phase conductors CY.

[0026] In this way, by dividing the AC current of two of the u, v, and w phases into multiple conductors C and placing them inside a cylindrical conductor CT through which AC current of a different phase flows, the area over which different phases face each other can be increased even if the conductors are in the form of a general round wire rather than a flat wire.

[0027] In order to increase the area where different phases face each other, the three-phase AC electric wire 1 may be arranged such that conductors other than the tubular conductor CT have a C-shaped cross section and are placed inside the tubular conductor CT, as shown in Fig. 5. In the three-phase AC electric wire 1 shown in Fig. 5, each of the conductors carrying two-phase AC currents other than the AC current flowing through the tubular conductor CT is a C-shaped conductor CC whose cross section perpendicular to the longitudinal direction DL is C-shaped, and is placed inside the tubular conductor CT so as to form a tubular body with a smaller diameter than the tubular conductor CT.

[0028] The three-phase AC electric wire 1 shown in FIG. 5 includes a C-shaped conductor CC whose cross-sectional shape in a virtual plane VP perpendicular to the longitudinal direction DL is a C-shape that is open in one of the four directions (up, down, left, and right). The three-phase AC electric wire 1 shown in FIG. 5 includes two C-shaped conductors: a first C-shaped conductor CC1 and a second C-shaped conductor CC2. The three-phase AC electric wire 1 shown in FIG. 5 is a round wire, and the cross-sectional shape of the C-shaped conductor CC is an arc shape that is the shape of a portion of a circumference, more specifically, a semicircular arc shape that is the shape of a circle divided in half. The two C-shaped conductors CC are arranged so that their open ends face each other and form a cylindrical body with a smaller diameter than the cylindrical conductor CT. The two C-shaped conductors CC are not in contact with each other but are arranged at a distance from each other.

[0029] In the three-phase AC electric wire 1 shown in FIG. 5, the outer surface of the C-shaped conductor CC is arranged along the inner peripheral surface of the tubular conductor CT, so that a wide facing area can be secured between the tubular conductor CT and the C-shaped conductor CC.

[0030] By arranging the two C-shaped conductors CC facing each other with their open ends facing each other and forming a cylindrical conductor with a smaller diameter than the cylindrical conductor CT, it is possible to ensure a wide area where the conductors face each other. This can also be demonstrated, for example, when the three-phase AC wire 1 is a flat wire as shown in FIG. 6.

[0031] In an embodiment in which two C-shaped conductors CC are arranged facing each other at a distance to form one tubular body, as in the three-phase AC electric wire 1 illustrated in Figures 5 and 6, a tubular conductor CT may be arranged inside them, as shown in Figure 7. In the three-phase AC electric wire 1 shown in Figure 7, conductors for carrying two-phase AC currents different from the AC current of the phase carried by the tubular conductor CT are arranged outside the tubular conductor CT, and each of the conductors for carrying the two-phase AC currents is a C-shaped conductor CC whose cross section perpendicular to the longitudinal direction DL is C-shaped, and is arranged so as to cover the tubular conductor CT from the outside.

[0032] 5 and 6, the two C-shaped conductors CC are arranged to form a tubular body that is smaller than the inner dimensions of the tubular conductor CT, whereas the three-phase AC electric wire 1 illustrated in Fig. 7 has the two C-shaped conductors CC arranged to form a tubular body that is larger in diameter than the tubular conductor CT and has inner dimensions that can accommodate the tubular conductor CT. In this case, too, it is possible to ensure a wide area where the conductors through which AC currents of different phases flow face each other.

[0033] The three-phase AC electric wire 1 of the present invention can have a reduced inductance by having the above-described structure. Note that the three-phase AC electric wire 1 of the present invention can adopt various forms other than those exemplified above, and is not limited to the above-described examples. This specification includes the following disclosures.

[0034] [1] A three-phase AC electric wire having conductors through which the u-phase, v-phase, and w-phase of three-phase AC flow, having a length direction, The conductor of one of the u-phase, v-phase, and w-phase is a cylindrical conductor having a circular cross section perpendicular to the longitudinal direction, The conductors of the other two phases are: Either both are disposed inside the cylindrical conductor, or both are disposed outside the cylindrical conductor, The conductors through which the phases flow are: A three-phase AC wire arranged to face the conductor carrying two other phases.

[0035] [2] The cross-sectional shape of the cylindrical conductor is oval or rectangular, and has a minor axis direction and a major axis direction, The conductor through which two phases other than the cylindrical conductor flow is Each of the strip-shaped conductors is disposed inside the cylindrical conductor so that the long diameter direction is the width direction, The three-phase AC electric wire according to [1], wherein the strip-shaped conductors are arranged inside the tubular conductor so as to overlap with each other at a distance in the minor axis direction.

[0036] [3] The conductors of two phases other than the cylindrical conductor are arranged inside the cylindrical conductor, The three-phase AC electric wire according to [1] or [2], wherein a plurality of the conductors through which the two phases flow are provided inside the cylindrical conductor.

[0037] [4] The conductors of two phases different from the cylindrical conductor are arranged outside the cylindrical conductor, Each of the conductors of the two phases has The three-phase AC electric wire according to [1], wherein the cross section perpendicular to the longitudinal direction has a C-shape and is disposed so as to cover the cylindrical conductor from the outside.

[0038] [5] Each of the two phase conductors other than the cylindrical conductor is The cross section perpendicular to the longitudinal direction has a C-shape, The three-phase AC electric wire according to [1], wherein the cylindrical conductor is disposed inside the cylindrical conductor so as to form a cylindrical body having a smaller diameter than the cylindrical conductor. [Example]

[0039] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. (Comparative Examples 1 to 3, Examples 1 to 4) Simulations were performed using three-phase AC electric wires of Comparative Examples 1 to 3 and Examples 1 to 4 under the conditions shown in Fig. 8. Note that Comparative Examples 1 to 3 differ from the three-phase AC electric wires of the Examples in that the conductors through which the three-phase AC currents flow face each other but do not have a tubular conductor. In the simulations, the conductor resistance (conductor resistance) was calculated when a 50 kHz three-phase AC current was passed compared to when a DC current was passed, and the ratio to when a DC current was passed (conductor resistance increase rate) was also calculated, along with the inductance, reactance, and impedance when a 50 kHz three-phase AC current was passed.

[0040] The results are shown in Figure 9, and it can be seen from the results shown in the figure that although inductance can be reduced to some extent by increasing the facing area as in Comparative Example 3, the inductance is reduced even more significantly by providing a cylindrical conductor. It can also be seen from the results shown in the figure that inductance can be further reduced by providing multiple conductors other than the cylindrical conductor that carry two phases of current, or by making these conductors C-shaped in cross section.

[0041] (Comparative Example 4, Example 5) A comparison was made between the three-phase AC electric wire of Comparative Example 4, which has the common feature of having the conductors arranged concentrically as shown in Fig. 10, and the three-phase AC electric wire of Example 5, in which two tubular conductors, one inner and one outer, are provided, with the remaining conductor provided at the center of the inner tubular conductor, and the inner tubular conductor faces the conductors of the other two phases while the outer tubular conductor and the conductor provided at the center face only the conductor of the other phase, and the three-phase AC electric wire of Example 5, in which two C-shaped conductors are arranged to form one tubular conductor, and the three-phase conductors are arranged to face each other. As a result, as shown in Fig. 10, it was found that the three-phase AC electric wire of Example 5 was superior in all of inductance, reactance, and impedance.

[0042] (Comparative Example 5) As shown in Figure 11, Example 4, in which two C-shaped conductors (conductors with a semicircular arc cross-sectional shape) are arranged inside one tubular conductor to form one tubular conductor, and Example 5, in which two C-shaped conductors (conductors with a semicircular arc cross-sectional shape) are arranged outside one tubular conductor to cover the tubular conductor from the outside, are superior in all of inductance, reactance, and impedance compared to Comparison Example 5, in which three arc-shaped conductors are arranged to form one tubular conductor.

[0043] (Comparative Example 6, Example 6) A comparison was made between Comparative Example 6 and Example 6 using a flat line as shown in Fig. 12. This simulation result also showed that Example 6 was superior in all of inductance, reactance, and impedance.

[0044] From the above, it can be seen that the present invention provides a three-phase AC electric wire with reduced inductance. [Explanation of symbols]

[0045] 1: 3-phase AC wire, 10: wire body, 20: sheath, CAX: central axis, C: conductor, CB: strip conductor, CC: C-shaped conductor, CT: cylindrical conductor, DL: Length direction, DR: Circumferential direction, DT: Minor axis direction, DW: Major axis direction, V: Internal space, VP: Virtual plane

Claims

1. A three-phase AC electric wire having conductors through which u-phase, v-phase, and w-phase of three-phase AC respectively flow, having a length direction, The conductor of one of the u-phase, v-phase, and w-phase is a cylindrical conductor having a circular cross section perpendicular to the longitudinal direction, The conductors of the other two phases are: Either both are disposed inside the cylindrical conductor, or both are disposed outside the cylindrical conductor, The conductors through which the phases flow are: A three-phase AC electric wire arranged to face the conductor through which two other phases flow.

2. The cross-sectional shape of the cylindrical conductor is oval or rectangular, and has a minor axis direction and a major axis direction, The conductor through which two phases other than the cylindrical conductor flow is Each of the strip-shaped conductors is disposed inside the cylindrical conductor so that the long diameter direction is the width direction, 2. The three-phase AC electric wire according to claim 1, wherein the strip-shaped conductors are arranged inside the cylindrical conductor so as to overlap each other with a gap in the minor axis direction.

3. The conductors of two phases different from the cylindrical conductor are arranged inside the cylindrical conductor, 2. The three-phase AC electric wire according to claim 1, wherein a plurality of conductors for carrying the two phases are provided inside each of said cylindrical conductors.

4. the conductors of two phases separate from the cylindrical conductor are arranged outside the cylindrical conductor, Each of the conductors of the two phases comprises:

2. The three-phase AC electric wire according to claim 1, wherein the cross section perpendicular to the length direction has a C-shape and is disposed so as to cover the cylindrical conductor from the outside.

5. Each of the two phase conductors other than the cylindrical conductor is The cross section perpendicular to the longitudinal direction has a C-shape, 2. The three-phase AC electric wire according to claim 1, wherein the conductor is disposed inside the cylindrical conductor so as to form a cylindrical body having a smaller diameter than the cylindrical conductor.

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