JPS5929134B2 - current transformer primary conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a primary conductor in a current transformer comprising an eyebolt-shaped primary conductor having a winding portion with a predetermined number of turns, and an annular iron core intersecting the eyebolt-shaped primary conductor.

This type of current transformer primary conductor has already been filed by the same applicant as U.S. Pat. No. 51-98725.

FIG. 1 shows the primary conductor of a current transformer according to this application. The number of turns of the winding part 1 is 2 turns as an example, and both ends 1a and Ib are concentrically arranged tubular conductors 2a and 2b.
It is connected to a straight part consisting of In this case, winding part 1
has the following structure.

First, as shown in Figure 2, a primary conductor with a half-moon cross section. From the beginning of the volume A shown in the figure, sequentially B→C→D→E-■F→G→H
→A primary conductor is made with a half-turn twist for one turn, and a tubular conductor 2 is attached to the winding start end A, i.e. 1a, and the winding end end I, Ib, respectively, as shown in Fig. 1.
A and 2b are connected. Here, since the primary conductor is twisted half a turn per turn as described above, the winding portion is made of two half-moon cross-section conductors Id with a thin insulator Ic in between, as shown in Figure 3. , Ie are combined into a single circular cross section, and by surrounding it with an insulator lf to make it a single piece, the structure becomes extremely strong, and at the same time, the smooth surface of the conductor makes it suitable for preventing electric field concentration. This has the effect of eliminating the need for a shield. However, when the cross-section of the winding part formed by combining two turns of conductor is circular, the surrounding insulator 1f is as shown in the figure.
The side facing the iron core 3 at ground potential, that is, the inside of the winding portion, becomes thick.

For this reason, the inner diameter L1 of the winding portion cannot be made very large, and therefore the cross-sectional area of the annular iron core 3 also becomes small. So, iron core 3
When the cross-sectional area of the current transformer is constant, it is necessary to increase the winding diameter L2 of the winding part 1, and as a result, the shape of the entire current transformer becomes larger, which increases the weight and price. There was a drawback. The present invention solves this drawback and will be explained below.

FIG. 4 shows an embodiment of the present invention, and as an example, the winding portion has two windings.
It shall be of the turn.

Here, the primary conductor constituting the winding portion 4 has two turns combined to form an oblong cross section such as an elongated ellipse in the direction of the winding axis, as shown in the figure. FIG. 5 shows the cross-sectional shape of the primary conductor, and in the negative conductor constituting the winding portion 4 of FIG. 5A, the cross sections at 41, 42, 43, and 44 change sequentially as shown in FIG. That is, the cross-sectional shape is twisted by 1/2 turn per turn so that two turns of the conductor are combined to form an oval cross-section that is always long in the direction of the winding axis. With such a cross-sectional shape, the conductors 4b and 4c are combined by sandwiching a thin insulator 4a between the conductors, and an insulating layer 4d is applied around the periphery, as shown in FIG. Even if the thickness of
As shown in the figure, the inner diameter L} of the winding portion can be made much larger than the case of FIG. 3 compared to the winding radius of the conductor.

Therefore, the cross-sectional area of the iron core 3 can be increased, and if the cross-sectional area of the iron core 3 is constant, the winding diameter of the winding part can be made smaller than in the case of FIG. The shape can be reduced. The conductor used for this is the 5th conductor.
As shown in Figure b, the cross-sectional shape changes sequentially, but by making one turn of a conductor made of cast metal such as copper or aluminum and connecting them in series, it is easy to create a two-turn winding. can be formed.

Next, FIG. 6 shows an example in which a cooling medium flow path is provided in the conductor of the winding portion of the above structure.

This is the primary conductor 5 sandwiching the thin insulating layer 5a of the winding portion 5.
An insulating layer 5d is provided around the bn5c, and a recess is provided in the opposing surfaces of the primary conductors 5b and 5c to form a cooling medium flow path 5e, so that a cooling medium such as insulating oil can flow from the outside. By cooling the primary conductor in this manner, it is also possible to downsize the primary conductor. In addition, each of the above embodiments shows the case where the winding part has two turns, but when the number of turns is n turns, a twist of 1/n rotation is applied for each turn, and The object of the present invention can be achieved by configuring the conductors to be combined to form an oval cross section that is elongated in the direction of the winding axis.

In addition, the conductor used for this has a cross-sectional shape that changes sequentially during one turn, but as mentioned above, each turn is cast and connected in series to easily form a winding section with a predetermined number of turns. can be configured. Furthermore, the present invention is not limited to the case where the winding part has multiple turns, but even when the winding part has one turn, the object can be achieved by making the primary conductor have an oval cross section that is long in the direction of the winding axis. can be reached.

As described in detail above, according to the present invention, it is possible to downsize the current transformer by making the inner diameter of the winding part larger than the winding diameter of the winding part. By providing a flow path of 1, it is possible to achieve even greater effects in addition to miniaturization.

[Brief explanation of the drawing]

Figures 1A, b, and c are plan front and bottom views showing the primary conductor of a conventional current transformer, Figure 2 is an explanatory diagram showing the structure of the primary conductor, and Figure 3 is the same primary conductor and iron core. 4 and 6 are cross-sectional views showing each embodiment of a current transformer using a primary conductor according to the present invention, and FIG. 5A,
b is an explanatory diagram showing the cross-sectional shape of one turn of the primary conductor in the present invention. 3; Iron core, 4; Winding portion, 4a; Insulating layer, 4b, 4c; Primary conductor, 4d; Insulating layer, 5; Winding portion, 5a; Insulating layer, 5
b, 5c; primary conductor; 5d; insulating layer; 5e; cooling medium flow path.

Claims (1)

[Scope of Claims] 1. A current transformer comprising a winding portion made of an n-turn primary conductor that is insulated from each other and twisted by 1/n rotation per turn, and an iron core that intersects the winding portion. In,
A current transformer primary conductor, wherein the n-turn primary conductors are combined to form an oval cross section that is elongated in the direction of the winding axis of the winding portion. 2. In the current transformer primary conductor according to claim 1, the n-turn winding portion is constructed by connecting n cast one-turn primary conductors in series. Current transformer primary conductor. 3. In the primary conductor of a current transformer according to claim 1, the winding portion is constituted by one turn of the primary conductor, and the primary conductor has an oval cross section that is long in the direction of the winding axis of the winding portion. A current transformer primary conductor characterized by: 4. In the primary conductor of a current transformer according to claim 1 or 2, recesses are provided in the opposing surfaces of the n-turn primary conductor to serve as a flow path for a cooling medium, and the cooling medium is supplied from the outside. A current transformer primary conductor characterized by free circulation. 5. A current transformer primary conductor according to claim 3, characterized in that a cooling medium flow path is provided in the one-turn primary conductor, and the cooling medium is allowed to flow freely from the outside. vessel primary conductor.