JPS6259448B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molded transformer having two coils on the low voltage side, and particularly to the structure of the low voltage side coil.

As a transformer to which a thyristor rectifier or the like is connected on the low voltage side, a molded transformer with triangular wiring on the high voltage side and double star wiring on the low voltage side is used. FIG. 1 is a vector diagram of induced voltage in this type of transformer, where the left side of the slope line is the high voltage side and the right side is the low voltage side.

As shown in FIGS. 2 and 3, this type of molded transformer is a molded low-voltage transformer in which two coils 2 and 3 in the same phase are integrally molded with a resin molded body 4 around the outer periphery of an iron core 1. A coil 5 is arranged,
Furthermore, a molded high voltage coil 8, which is formed by integrally molding the high voltage coil 6 with a resin mold body 7, is disposed on the outer periphery thereof. In particular, the molded low voltage coil 5 has the following configuration in order to equalize the % impedance of the two coils, that is, the first coil 2 and the second coil 3. That is, the first coil 2 and the second coil 3 are each composed of inner coil parts 2A, 3A and outer coil parts 2B, 3B, and the outer coil part 2B of the first coil is composed of the inner coil part 3A of the second coil.
The outer coil portion 3B of the second coil is arranged outside the inner coil portion 2A of the first coil, and the inner coil portion 2A and the outer coil portion 2B of the first coil are connected to the first connecting conductor. 9
The inner coil portion 3A and outer coil portion 3B of the second coil are connected by a second connection conductor 10, respectively.

In this type of molded transformer, since a large current flows on the low voltage side, the inner coil portions 2A, 3A
Generally, the outer coil portions 2B and 3B are each formed by winding a sheet-like conductor. In addition, the inner coil portions 2A, 3A and the outer coil portions 2B, 3B have external lead-out conductors 11A,
12A, 11B, and 12B are connected. The terminal symbols u, x, o ₁ , o ₂ of each external lead-out conductor correspond to those in FIG. 1.

A conventional molded transformer having two coils on the low-voltage side is constructed as described above, but this transformer has the disadvantage that manufacturing the low-voltage coil is troublesome and increases the cost.

That is, for example, when manufacturing the molded low-voltage coil 5 of the transformer shown in FIG. 2, first, the inner coil portions 2A and 3A are wound around a mold. An external lead conductor 11A is welded to the winding start end of the inner coil portion 2A, and a connection conductor 10 is welded to the winding start end of the inner coil portion 3A. However, if the connecting conductor 10 has the shape shown in the figure, its outer end side (the part to be welded to the outer coil part 3B) becomes a sag, making it impossible to wind the inner coil part 2A of the first coil. From this point on, the outer end side of the connecting conductor 10 is bent in a direction perpendicular to the axis until the winding of the coil is completed. When the winding of the inner coil portions 2A and 3A is completed, the connection conductor 9 is welded to the end of the winding of the inner coil portion 2A, and the external lead conductor 12A is welded to the end of the winding of the inner coil portion 3A. after that,
The outer coil portions 2B, 3B are wound. A connection conductor 9 is provided at the winding start end of the outer coil portion 2B, and an external lead conductor 12 is provided at the winding start end of the outer coil portion 3B.
B is welded in advance. Outer coil part 2B,
3B, the external lead conductor 11B is placed at the end of the winding of the outer coil portion 2B.
A connecting conductor 10 is welded to the end of the winding B. Since the connecting conductor 10 was bent perpendicularly to the axis during coil winding, it was
When welding to B, it is necessary to bend it into the shape shown in the figure. However, since the connecting conductor 10 is narrower than the sheet-like conductor of the coil and thicker, it cannot be bent into the shape shown in the figure while attached to the inner coil portion 3A. is extremely difficult.

Further, when manufacturing the molded low voltage coil 5 of the transformer shown in FIG. 3, the inner coil portions 2A and 3A are first wound around the mold as described above. External lead-out conductors 11A and 12A are welded to each winding start end. After winding the inner coil parts 2A and 3A, connect the connecting conductors 9 and 1 to the end of each winding.
Weld 0. Next, after welding the winding start ends of the outer coil portions 2B and 3B to the connection conductors 9 and 10 (this welding is performed between the connection conductors 9 and 10 and the inner coil portion 2
(This may be done before welding with A and 2B), and the outer coil portions 2B and 3B are wound. After winding of the outer coil portions 2B and 3B is completed, external lead conductors 11B and 12B are welded to the winding ends of the respective outer coil portions (this welding may also be performed in advance before winding of the outer coil portions).

The molded low-voltage coil shown in FIG. 3 is easier to manufacture than the one shown in FIG. 2 because there is no bending of the connecting conductor after winding the coil. However, in any case, manufacturing the low-voltage coil is troublesome because welding of the connecting conductor is required between the winding of the inner coil and the winding of the outer coil, which is a factor in increasing costs. ing.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a molded transformer equipped with a molded low-voltage coil that does not require welding of connecting conductors during coil winding.

To achieve this objective, the present invention provides a molded transformer in which the two low-voltage coils each consist of an inner coil part and an outer coil part, in which the inner coil part and the outer coil part are separately molded and arranged concentrically. At the same time, each of the inner coil part and the outer coil part is provided with a connection lead-out conductor drawn out to the outer end of the coil part, and the connection between the corresponding connection lead-out conductors is made by separately molding the inner coil part and the outer coil part. It is characterized in that it is connected by a connection conductor separate from the resin molded body inserted therebetween.

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

In this embodiment, a resin mold body 13 for molding the inner coil portions 2A, 3A and a resin mold body 1 for molding the outer coil portions 2B, 3B are used.
4 are separate bodies, and they are arranged concentrically. Further, connecting lead-out conductors 15A, 16A, 15 are provided at the end of the winding of the inner coil portions 2A, 3A and the beginning of winding of the outer coil portions 2B, 3B, respectively.
B and 16B are welded together, and their connecting lead conductors are led out to the outer end of the coil portion. and,
The first connection conductor 17 connects the corresponding connection draw-out conductors 15A and 15B of the first coil 2 to connect the connection draw-out conductors 1 of the second coil 3.
6A and 16B are connected by a second connection conductor 18, respectively. The connecting conductors 17 and 18 are
It is inserted into the gap 19 between the two resin molded bodies 14 and 15, and as shown in FIG. 5, they are arranged at an appropriate distance apart in the circumferential direction.

As the resin for the mold, an epoxy resin composition, for example, a resin composition comprising an epoxy resin, an isocyanurate, and a basic catalyst, is used.

Since the configuration other than the above is the same as that of the conventional example shown in FIG. 3, the same parts are given the same reference numerals and detailed explanations will be omitted.

According to this embodiment, the inner coil part and the outer coil part of the low-voltage coil are manufactured separately, and the connection lead-out conductor and the connection conductor are welded and connected during terminal welding work etc. during assembly. Therefore, there is no need to weld the connecting conductor during the coil winding operation as in the conventional method, and manufacturing of the low voltage coil becomes extremely easy. In addition, the inner coil part and outer coil part are molded separately, and a gap is provided between the two resin molded bodies, so there is a large heat dissipation area, which reduces the temperature rise of the low voltage coil through which large current flows. effective. This gap also has the advantage that a connecting conductor can be inserted through it.

In the above embodiment, the case where the inner coil part and the outer coil part were constructed of sheet-like conductors was explained, but each coil part is made by stacking coil units made by winding narrow conductors in the axial direction and connecting them in parallel or in series. It may also be composed of connected devices.

As explained above, according to the present invention, in a molded transformer in which the two coils on the low voltage side are each composed of an inner coil part and an outer coil part, the inner coil part and the outer coil part of the two coils are connected midway. Since it is now possible to wind the connecting conductor without welding, it becomes extremely easy to manufacture low-voltage coils with complex structures, and costs can be reduced.

In addition, the inner coil part and the outer coil part are molded separately, and a gap is provided between the two resin molded bodies, so there is a large heat dissipation area, reducing the temperature rise of the low voltage coil through which large current flows. Furthermore, there is an advantage that the connecting conductor can be inserted through the gap by effectively utilizing the gap.

[Brief explanation of the drawing]

Figure 1 is a vector diagram of the induced voltage of a triangular connection transformer on the high voltage side and a double star connection transformer on the low voltage side. Figures 2 and 3 are sectional views showing the structure of one phase of a conventional molded transformer, respectively. FIG. 4 is a sectional view showing the structure of one phase of a molded transformer according to an embodiment of the present invention, and FIG. 5 is an end view of the transformer. 1...Iron core, 2...First coil, 2A...Inner coil part, 2B...Outer coil part, 3...Second coil, 3A...Inner coil part, 3B...Outer coil part, 5... Molded low voltage coil, 8
...Molded high voltage coil, 11A, 11B,...
...12A, 12B...External drawer conductor, 15A,
15B, 16A, 16B...Connection lead-out conductor, 1
7, 18... Connection conductor.

Claims (1)

[Claims] 1. An iron core, a molded low-voltage coil placed on the outer periphery of the iron core, and a molded high-voltage coil placed on the outer periphery of the iron core, the molded low-voltage coil having a first coil and a second coil. and each of these two coils includes an inner coil portion and an outer coil portion, and the outer coil portion of the first coil is attached to the outer periphery of the inner coil portion of the second coil. The outer coil portions are respectively arranged on the outer periphery of the inner coil portion of the first coil, and the inner coil portion and the outer coil portion are separately molded and arranged concentrically, and the inner coil portion and the outer coil portion Each coil part has a connection lead-out conductor drawn out to the outer end side of the coil part, and a resin mold inserted between the separately molded inner coil part and outer coil part is inserted between the corresponding connection lead-out conductors. A molded transformer characterized in that it is connected by a connecting conductor that is separate from the body. 2. The molded transformer according to claim 1, wherein the inner coil portion and the outer coil portion are formed by winding a sheet-like conductor. 3. The molded transformer according to claim 1, wherein the inner coil portion and the outer coil portion are comprised of a plurality of coil units stacked in the axial direction and connected in parallel or in series.