JPH0594906A - Magnetic material - Google Patents

Abstract

PURPOSE:To provide magnetic material having a copper coated layer to be used by winding on a wire for prevention of snow and ice accretion on a copper arial transmission line. CONSTITUTION:This magnetic material is formed by providing a high conductive copper coated layer of uniform thickness around a magnetic body, and the high conductive metal coated layer is accounted for 15 to 40% of the total cross-section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic material which is used by being wound around an electric wire for the purpose of preventing freezing of the overhead transmission and distribution wire.

[0002]

2. Description of the Related Art In winter, in cold regions, especially in northern Japan or back Japan, overhead power lines are subject to snow and ice, which grows to a considerable size and increases the weight of wires in the span and wind pressure. In many cases, this leads to an increase in load, which leads to an increase in the strength of the electric wire, breakage of the electric wire due to excessive tension, and even an accident such as the collapse of a tower. In addition, if the icing snow falls into a block shape and falls, there is a danger to people passing under the overhead line, and even if the overhead line is farmland, it may damage crops, vinyl houses, etc. Therefore, it is desired to solve this problem. For this reason, as measures to prevent snow accretion, there has been a method of melting by conductor Joule heat by temporary high-current power transmission, or a method of attaching a ring-shaped thing to a power transmission line and dropping a snow accretion. However, large-current power transmission is limited by the operation of the electric power system and cannot be implemented freely.Even if a ring-shaped one is attached, the effect varies depending on the type of icing snow. If you simply drop the, there is a possibility that a secondary disaster will occur at the point of fall,
It is not a sufficient measure.

On the other hand, a sleeve made of a magnetic material on the AC power transmission line or a linear body processed in a spiral shape, a tape,
Hysteresis loss caused by winding a rod etc. and the AC magnetic field due to the transmitted electric current passing through the sleeve etc.
A method of melting snow by utilizing heat loss due to eddy current has also been proposed, but if these sleeves, wires, tapes, and rods are wound around an electric wire, the electric wire weight increases. In addition, heat generated from the magnetic material at a temperature at which icing and snow does not occur increases transmission loss, so
A material having a low Curie point, which does not generate heat due to deterioration of magnetic properties at high temperatures, is desirable. The so-called low Curie point material having a Curie point near room temperature is generally characterized by a smaller holding force than a material having a high Curie point. Therefore, the desired snow melting effect cannot be expected only with the hysteresis loss related to heat generation, and it is necessary to use heat generation due to eddy current loss together.

[0004]

When the Curie point of the magnetic material is high (300 ° C. or higher), heat generation due to hysteresis loss is larger than heat generation due to eddy current loss, so that the thickness of the coating material changes. But that doesn't make a big difference.
However, when the Curie point is low (200 ° C or lower), the heat generated by the current becomes larger than the heat generated by the hysteresis loss. Therefore, the snow melting effect can be seen unless the thickness of the highly conductive metal coating layer is appropriately determined. There will be problems such as no.

[0005]

As a result of various investigations, the present inventors have found that when a copper-based low resistance material is coated with a uniform thickness around a magnetic material, the thickness of the coating material is The area ratio of the cross-sectional area occupied by the copper-based conductive material to the cross-sectional area is 15 to 4
0%, and more preferably 20 to 30%
To provide a magnetic material. When the area ratio of the copper-based highly conductive material is less than 15%, the effect of coating the copper-based conductive material is too small, and it is considered to be particularly effective when it is 20% or more.
On the other hand, when a copper-based conductive material having a thickness of more than 40% is coated, heat generation is reduced, which is inappropriate. The magnetic material used in the present invention is preferably a Ni-Cr-Si-Fe based alloy, and particularly preferably Cr having a weight of 3.1% by weight or less and a circular cross section.

[0006]

EXAMPLES The present invention will be described below with reference to examples. Example 1 54 wt% Ni, 9 wt% Cr, 5 wt% Si, balance F
The alloy wire consisting of e is vacuum melted and melted to a diameter of 30 mm.
It was cast with the mold. After processing this alloy into a wire having a diameter of 10 mm by cold forging and wire drawing, the alloy wire is polished,
A copper pipe of 0.3 to 2.0 mm thickness is coated so that the coating thickness is 15, 25, 33, 40% and 47% in area ratio, and wire drawing and strain relief to a diameter of 2.0 mm. Was performed to prepare a sample. Comparative Example 5 A sample was prepared in the same manner as in Example 4 except that the copper tube was not covered and wire drawing and strain relief were performed to a diameter of 2.0 mm. Example 1
The heat generation was measured when the line of Comparative Example 1 was subjected to an alternating magnetic field of 30 Oe and the direction of the magnetic field was aligned with the axial direction of the line. The result is shown in FIG. From Fig. 1, the case of copper pipe coating is also 3
It is 15 to 40 that the value of 30 Watt / kg or more is 0 Oe.
% Is required.

[0007]

According to the present invention, snow and water on copper-based overhead power transmission lines can be melted and removed by an extremely simple means, and the effect is particularly great in the case of strain relief processing. It was a big one.

[Brief description of drawings]

FIG. 1 is a graph showing a copper area ratio (%) and a heat generation amount per 1 kg (Watt / kg) of a copper pipe-coated magnetic material according to the present invention.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Sasaki 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd.

Claims (2)

[Claims] 1. A coating layer of a copper-based highly conductive metal material having a uniform thickness, which is provided around a magnetic body, has a total cross-sectional area ratio of 15 to 50.
Magnetic material characterized by being 40% 2. The magnetic material according to claim 1, wherein the copper-based highly conductive material coating layer is strain-relieved after wire drawing.