JPH0416414Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a transformer using a strip-wound coil whose conductor is a thin plate or foil made of aluminum, copper, or the like.

(Prior Art) In general, a strip-wound coil 2 is manufactured by connecting a strip conductor 2' to an outlet conductor 1a at the beginning of winding by welding or pressure welding, as shown in FIG. It is constructed by rolling up 2'. Although only one strip conductor 2' is used in FIG. 3, for example, two or more strip conductors may be wound side by side in the winding axis direction.

The strip conductor 2' is a thin plate or foil made of a conductive material such as aluminum or copper and has a thickness of about 0.1 mm to 3 mm, and is generally shipped after being rolled, slit, and end-faced at a material rolling manufacturer. End face treatment refers to the process of chamfering any burrs or the like that have occurred on the end face after slitting. The strip conductors 2' for electrical equipment coils are end-face treated to prevent damage to the inter-turn insulation and excessive electric field concentration at the edges.

FIG. 4 is a sectional view showing an example of a transformer using such a strip-wound coil 2. A low voltage winding 5 is wound around the outer periphery of the iron core 4, and a high voltage winding 6 is further wound concentrically around the outer periphery. Here, an example is shown in which a strip-wound coil 2 is used as the low-voltage winding 5.
Of course, a strip-wound coil may also be used for the high voltage winding 6, or contrary to FIG. 4, a high voltage winding may be used on the inside and a low voltage winding on the outside.

Now, a transformer using such a strip coil 2 has the following problems. That is, as the insulation class of the transformer increases, the requirements for insulation of the winding become stronger. For insulation, for example, the fourth
The distance d or d' between the electrodes in the figure may be increased, the end of the winding 6 may be covered with an insulating flange 7, or an electrostatic shield 8 may be used to prevent electric field concentration at the end of the winding. I will set it up. However, in the strip-wound coil 2, insulation between adjacent turns is maintained by the creep distance l of the inter-turn insulating paper 3, so it is impossible to avoid concentration of electric fields by providing the electrostatic shield 8. For this reason, it is necessary to further widen the distance d between the electrodes, but increasing the distance d between the electrodes leads to an increase in the size of the device and is not a good idea.

As a first conventional method for dealing with such a problem, for example, as shown in FIG. 4, there is a method in which shield conductors 9 for mitigating the electric field are provided on the inner and outer peripheries of the ends of the strip-wound coil 2. The electric field mitigation shield conductor 9 is made of a round bar made of copper or the like and coated with an insulating coating such as paper, and is provided on the outer or inner circumference of the strip coil 2 as shown in the figure. As a result, the degree of concentration of the electric field is determined by the curvature of the shield conductor 9. It is possible to obtain a much larger radius of curvature than at the end of the strip conductor 2', which has zero points of several millimeters at most, and the degree of concentration of the electric field is greatly reduced.

However, on the other hand, the distance d between the electrodes had to be increased by the size of the sole conductor 9, which led to an increase in the size of the device.

Next, FIG. 5 shows a second method that attempts to solve the above-mentioned drawbacks, in which the width of a single strip conductor 2' is successively narrowed at the position facing other electrodes to form an arcuate end portion of the winding. The equivalent radius of curvature is increased and the concentration of the electric field is alleviated. In this case, since the shield conductor 9 shown in FIG. 4 is not used,
The electric field distance d can be reduced by that amount. but,
This structure has the following drawbacks.

First, since the width of the strip conductor 2' is narrowed from the middle, the cross-sectional area is reduced by that amount, resulting in an increase in resistance and load loss. This is a problem that cannot be overlooked in today's equipment, which is strongly required to save energy.

Second, in order to narrow the width of the strip conductor 2' midway, it is necessary to perform a slitting operation in which the ends of the strip conductor 2' are cut off during the winding process, and an accompanying end surface processing operation. . Such work tends to generate metal foreign matter such as chips, and if foreign matter should get mixed into the winding, it could damage the inter-turn insulating paper 3 and cause a short circuit between layers, leading to a serious accident. .

(Problems to be solved by the invention) As mentioned above, when a conventional strip-wound coil is used as a winding with a high insulation class, the electrodes are concentrated at the ends of the winding. Countermeasures have been devised. However, it has drawbacks, such as a limit to reducing the distance between electric fields and problems with the processing method.

An object of the present invention is to provide a transformer using a strip-wound coil that can sufficiently relax the electric field, minimize the distance between electrodes, and have good workability.

[Structure of the idea]

(Means and effects for solving the problem) The transformer of the present invention is a transformer in which a winding using a strip-wound coil whose conductor is aluminum or foil and other windings are arranged concentrically. In addition to making the axial length of the winding using a strip-wound coil longer than other windings, a shield conductor such as a round bar is installed at the end of the winding using a strip-wound coil that faces the other winding. It is characterized by its placement.

In the present invention, there is no need to increase the distance between the high and low voltage windings by using shielded conductors, and there is no need for the complicated process of processing the strip conductor during the winding process, which is likely to generate metal foreign matter.

(Example) The present invention will be described below with reference to the example shown in FIGS. 1 and 2. In FIGS. 1 and 2, the same reference numerals as shown in FIGS. 3, 4, and 5 indicate the same parts, so the explanation thereof will be omitted.

In the embodiment shown in FIG. 1, a low-voltage winding 5 employing a strip-wound coil 2 is arranged concentrically with another high-voltage winding 6. This low voltage winding 5 has an axial length of 2× compared to that of the high voltage winding 6.
It is made to be longer by Δh. A shield conductor 9 is disposed at the end of the low voltage winding 5 opposite to the end of the high voltage winding 6.

In this way, in the present invention, the axial length of the low voltage winding 5 is made longer than that of the high voltage winding 6, instead of increasing the distance d between the electrodes and arranging the shield conductor 9 as shown in FIG. By doing so, an insulation distance between the shield conductor 9 and the high voltage winding 6 is ensured. How long the axial length of the low voltage winding 5 should be determined depends on the distance between the shield conductor 9 and the high voltage winding 6 or the electrostatic shield 8 provided on the high voltage winding 6, and the distance between the low voltage winding 5 and the high voltage winding. 6, but in detail, it goes without saying that the electric field on the surface of the electrode such as the shield conductor 9 should be determined to be less than or equal to the allowable electric field.

Although the number of man-hours required to install the shield conductor 9 increases, there is no need for complicated elevations such as slitting the strip conductor 2' or processing the end faces as shown in Fig. 5, and there is no process that generates metal foreign matter. There is no risk of contamination in the winding. In addition, there is no need to increase the distance d between the high and low voltage windings when arranging the shield conductor 9 as shown in Fig. 4, and the minimum electric field determined from the impedance and the allowable electric field of the uniform electric field at the center of the winding height. Just the dimensions. Therefore, not only the dimensions of the entire winding can be reduced, but also the size of the entire transformer can be reduced, making it possible to provide a transformer with high reliability in terms of insulation.

Next, FIG. 2 shows another embodiment of the present invention, in which a deformed conductor having a substantially semicircular cross section instead of a round bar is used as the shield conductor 9'. In this way, the radius of curvature can be made even larger.

In the above explanation, the case where the low-voltage winding using a strip-wound coil is located on the inside has been representatively described, but it goes without saying that the present invention can also be applied to a transformer in which the low-voltage winding is wound on the outside. be. However, in this case, the shield conductor 9 will be arranged on the inner periphery of the strip-wound coil.

Effects of the invention As described above, according to the invention, the axial length of the winding using a strip-wound coil is made longer than other windings, and the length of the winding using a strip-wound coil is made longer than other windings. By arranging the shield conductor at the opposing ends, the electric field at the ends of the strip-wound coil can be relaxed without increasing the distance between the high and low voltage windings, and a transformer with good workability can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the winding arrangement of the transformer of the present invention, Fig. 2 is a sectional view showing another embodiment of the invention, and Fig. 3 is a perspective view showing the structure of a strip-wound coil. 4 and 5 are cross-sectional views showing winding arrangements of transformers using different conventional strip-wound coils, respectively. 2...Strip coil, 2'...Strip conductor, 3...Inter-turn insulator, 4...Iron core, 5...Low voltage winding, 6
... High voltage winding, 7 ... Insulating flange, 8 ... Electrostatic shield, 9, 9' ... Shield conductor.

Claims (1)

[Scope of utility model registration request] In a transformer in which a winding using a strip-wound coil whose conductor is a thin plate or foil made of aluminum or copper and other windings are arranged concentrically, the axial length of the winding using a strip-wound coil. is longer than other windings, and a shield conductor such as a round bar or approximately semicircular conductor is placed at the end of the winding using a strip-wound coil opposite to the other windings. vessel.