JP2779317B2 - Snow melting wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of winding a magnetic wire around an aluminum overhead electric wire and melting snow and icing on the aluminum overhead electric wire by heat generated by eddy current and hysteresis loss generated in the magnetic wire. A snow-melting electric wire, which has a high snow-melting effect even when a low current is applied, suppresses an excessive rise in temperature, and facilitates overhead wire construction.

[0002]

2. Description of the Related Art When snow or ice adheres to an overhead electric wire, the snow or ice develops while rotating along the twisted groove of the overhead electric wire, and finally becomes a huge cylindrical snow or ice block. As a result, a large load is applied to the overhead electric wire, which leads to disconnection of the overhead electric wire and collapse of the steel tower. As a countermeasure, a number of snow-resistant rings are attached to the outer circumference of the overhead electric wire at intervals, and the snow and ice accretion that rotates along the twisted grooves are stopped with these snow-resistant rings, and they fall before they become huge. The method of doing this has been put to practical use. However, this method has a problem that a vinyl house, a car, and the like directly below an overhead electric wire are damaged by falling snow or ice. Therefore, a magnetic wire is wound around the overhead electric wire, an eddy current and hysteresis loss are generated in the magnetic wire by an alternating magnetic field of an alternating current flowing through the overhead electric wire, and the heat generated at that time dissolves snow and icing on the overhead electric wire. A scumming method has been proposed (JP-A-58-44609).

[0003]

In the snow melting electric wire wound with the above magnetic wire, heat generated by eddy current or hysteresis loss of the magnetic wire during the daytime when power transmission is large (hereinafter abbreviated as eddy current heat).
It is difficult for snow and icing to occur due to the resistance heating of the overhead electric wire itself, but on the contrary, the overhead electric wire has risen above the allowable temperature and the amount of power transmission has to be reduced .
In order to solve this situation, the Curie temperature was lowered by changing the composition of the magnetic wire so that eddy current heat generation did not occur above a predetermined temperature.However, a magnetic wire with a low Curie temperature generally has a low magnetic flux density under a low magnetic field. However, sufficient eddy current heat was not obtained when the amount of power transmission was low in the early morning. Further, depending on the magnetic wire, electrolytic corrosion occurred between the overhead wire and the overhead wire, and the cross-sectional area of the overhead wire was substantially reduced. Also, when the overhead wire is wired through a wheel, the magnetic wire wound around the overhead wire shifts,
There has been a problem that the interval fluctuates and the initial snow melting effect cannot be obtained. The method of mounting the preformed magnetic wire after the overhead wire required a great deal of labor in the construction.

[0004]

Means for Solving the Problems The present invention has been made intensively in such a situation, and the purpose of the present invention is to generate sufficient heat even when the amount of power transmission is small, to adhere to snow and the like. It is an object of the present invention to provide a snow melting electric wire that melts ice quickly, does not generate excessive heat when electric power transmission is large, does not cause electrolytic corrosion, and can easily perform overhead wiring work. That is, the invention of claim 1 is:
In a snowmelt electric wire in which a magnetic wire is spirally wound around the outermost layer of an aluminum overhead electric wire, the magnetic wire is made of 40-60 wt% Ni.
%, The balance being Fe, wherein the magnetic wire is coated with an aluminum material to a thickness of 10 to 60 μm,
In the gap between the spirally wound aluminum-coated magnetic wires, an aluminum wire is wound as a spacer for keeping the interval between the aluminum-coated magnetic wires constant, and the aluminum-coated magnetic wires are It is characterized by projecting from the aluminum wire wound body.

[0005] The invention of claim 1 is a snow melting electric wire in which a magnetic wire is spirally wound around an overhead electric wire, wherein the displacement of the magnetic wire when passing through a wheel is prevented by interposing a spacer between the magnetic wires. Using a magnetic wire that generates a large amount of eddy current heat in a low magnetic field, the snow melting effect is enhanced, and excessive heat generation in a high magnetic field of the magnetic wire is suppressed by the fin cooling effect by winding the magnetic wire so that it protrudes from the spacer and winding the magnetic wire. In addition, the magnetic wire is coated with an aluminum material to prevent electrolytic corrosion with an overhead electric wire.

[0006] The alternating current flowing through the overhead electric wire generates an alternating magnetic field, and the alternating magnetic field causes eddy current loss and hysteresis loss in the magnetic wire wound around the overhead electric wire, and the magnetic wire generates heat. The amount of heat generated depends on the saturation magnetic flux density and the magnetic permeability of the magnetic wire. When an alternating magnetic field is applied in the axial direction of a soft magnetic wire having a circular cross section, most of the loss in the magnetic wire is an eddy current loss. This eddy current loss is proportional to the square of the magnetic flux density under a low magnetic field, and is proportional to the 1.6th power of the magnetic flux density under a high magnetic field. In any case, the higher the saturation magnetic flux density of the magnetic wire, the greater the amount of heat generated. For example, pure iron has a saturation magnetic flux density of 22,000 G, and generates a large amount of heat in a high magnetic field, but not so much in a low magnetic field. For the snow melting electric wire, a magnetic wire having a high magnetic flux density in a low magnetic field and a large calorific value is preferable.
Attention was paid to the i-based magnetic alloy. The saturation magnetic flux density of Fe is 22000 G as described above. When Ni is added to this Fe, the saturation magnetic flux density becomes the lowest at 4000 G at 30% of Ni,
When Ni exceeds 30%, the saturation magnetic flux density increases again, and N
It shows the maximum value at i 45 wt%. The magnetic permeability shows a maximum at 78% of Ni. An Fe—Ni alloy containing 40 to 60 wt% of Ni has a high saturation magnetic flux density of 14,000 G or more in a low magnetic field and a relatively high magnetic permeability. Therefore, it is advantageous as a magnetic wire for a snow melting electric wire. Therefore, in the present invention, Ni is reduced to 40
An alloy magnetic wire rod containing 6060 wt% and the balance of Fe was selected. The reason for limiting the Ni content to 40-60 wt% is that Ni
If it is less than 40 wt%, the magnetic permeability and the magnetic flux density in a low magnetic field decrease,
If the Ni content exceeds 60 wt%, the magnetic flux density in a low magnetic field is reduced, and in any case, the calorific value required for melting snow cannot be obtained.

According to the first aspect of the present invention, the aluminum material coated on the magnetic wire prevents electrolytic corrosion due to a potential difference from an overhead electric wire (aluminum conductor). When this magnetic wire is coated with an aluminum material, in a low magnetic field where the magnetic flux is not saturated, the magnetic flux of the magnetic wire is shielded by an eddy current which tries to cancel the external magnetic field flowing through the aluminum coating layer, and the calorific value is reduced.
On the other hand, in a high magnetic field where the magnetic flux is saturated, the amount of heat generated increases due to eddy current flowing through the magnetic wire and the aluminum coating layer. Therefore, if a magnetic material having a high saturation magnetic flux density and a high squareness ratio is used for the magnetic wire, the amount of heat generated in a low magnetic field can be increased even if the magnetic wire is coated with an aluminum material.

In the first aspect of the present invention, the aluminum material includes:
Pure aluminum or aluminum alloy is applied. In order to coat the magnetic wire with the aluminum material, an arbitrary method such as a hot dipping method, an electroplating method, or an aluminum pipe attaching method in which an aluminum tube is covered with a magnetic wire and drawn out is used. Aluminum coating thickness is 10μm
If it is less than 60 μm, a sufficient anticorrosion effect cannot be obtained.
The eddy current calorific value decreases. Also, it is difficult to coat an aluminum material exceeding 60 μm by a melt immersion method. In the electroplating method, when the plating thickness exceeds 60 μm, the plating surface becomes rough, and the above-described effect of improving heat generation by aluminum coating is reduced.
Therefore, surface polishing is required and the cost increases. For this reason, the coating thickness of the aluminum material is preferably 10 to 60 μm.

According to the first aspect of the present invention, the aluminum wire wound around the gap between the spirally wound magnetic wires plays a role as a spacer for keeping the interval between the aluminum-coated magnetic wires constant, and an overhead electric wire. The magnetic wire is prevented from being displaced when passing through the wheel, and its shape is arbitrary such as a circular cross section and a square. The aluminum wire protrudes the aluminum-coated magnetic wire from the wound aluminum wire so as not to hinder the fin cooling effect of the magnetic wire. By doing so, the heat generated by the magnetic wire at the time of the maximum allowable current is removed by its own fin cooling effect, and does not rise above the temperature of the overhead wire on which the magnetic wire is not wound. This aluminum wire for a spacer is wound on an overhead electric wire together with the magnetic wire.

A second aspect of the present invention is a snow melting electric wire in which a magnetic wire is spirally wound on the outermost layer of an aluminum overhead electric wire, wherein the magnetic wire contains 40 to 60 wt% of Ni and the balance of Fe It is a wire rod, and the magnetic wire rod has a zinc material of 10 to
An aluminum wire is wound as a spacer that keeps the interval between the aluminum-coated magnetic wires constant in the gap between the spirally wound aluminum-coated magnetic wires, which is coated with a thickness of 60 μm. The snow-melted electric wire, wherein the aluminum-coated magnetic wire protrudes from the aluminum wire-wound body.

The magnetic wire wound around the snow melting electric wire according to the first and second aspects of the present invention has a F content of 40 to 60 wt% Ni.
It is an e-Ni alloy. As described above, this alloy has a high saturation magnetic flux density in a low magnetic field of 14,000 G or more, and has a relatively high magnetic permeability. Therefore, it is useful as a magnetic wire for a snow melting electric wire. However, the present inventors have proposed that Ni is added to Fe in an amount of 3 to 78 wt.
% Alloy, the magnetostriction becomes positive, and when a tensile stress is left in the magnetic wire, the magnetic properties are improved and the calorific value is improved. We succeeded in improving the characteristics of Ni-based magnetic wires.

That is, according to a third aspect of the present invention, in a snow melting electric wire in which a magnetic wire is spirally wound around the outermost layer of an aluminum overhead electric wire, the magnetic wire contains Ni at 3 to 28 wt% or 35 to 65 wt%.
%, 0 to less than 10% by weight of Co, 0 to 9% by weight of Al, 0 to 7.5% by weight of Si, 0 to 4% by weight of V, an alloy containing 0 to 9% by weight of Cr and the balance of Fe, or 3% of Ni. ~ 65wt%, Co
10 wt% to 65 wt%, Al 0 to 9 wt%, Si 0 to 7.5
wt%, V is 0-4 wt%, Cr is 0-9 wt%, and the balance is F
e, an Al, Al alloy, Zn or Z having a thickness of 10 to 120 μm on the surface of the magnetic wire.
A snow-melting electric wire, which is coated with any metal of an n-alloy, and is wound around the metal-coated magnetic wire so that tensile stress remains during power transmission.

In the invention of claim 3, Ni is 3 to 28% by weight or 35 to 65% by weight, Co is less than 10% by weight, Al is 0 to 9% by weight,
0 to 7.5 wt% of Si, 0 to 4 wt% of V, 0 to 9 wt% of Cr
Alloy containing 3% and the balance being Fe, or 3-60 wt% Ni
%, 10 to 65 wt% of Co, 0 to 9 wt% of Al, and 0 to
An alloy containing 7.5 wt%, V of 0 to 4 wt%, Cr of 0 to 9 wt% and the balance of Fe is used for the magnetic wire.

The reasons for limiting the alloying elements are as follows: Ni and C
o is an alloy element that enhances the magnetic properties of the Fe-based material. In the former alloy, Co is less than 10 wt%, so Ni is 3 wt%.
If it is less than 10, sufficient positive magnetostriction cannot be obtained, and the magnetic properties will not be improved even if a tensile stress is left in the magnetic wire. Over 28wt%
If the amount is less than 35% by weight or exceeds 65% by weight, the magnetic flux density of the magnetic wire decreases, and the heat generated for melting snow cannot be obtained.
Further, in the latter alloy, Co is contained in a large amount of 10 to 65 wt%, so that even when the content of Ni is more than 28 wt% and less than 35 wt%, a magnetic flux density capable of obtaining a calorific value necessary for snow melting can be obtained.
Ni achieves good magnetic properties in a wide composition range of 3 to 65 wt%. Next, Al and Si have a function of increasing the magnetic flux density. When the content exceeds 9 wt% and 7.5 wt%, respectively, the magnetic flux density decreases instead. V improves cold workability. If its content exceeds 4 wt%, it will be too hard,
Conversely, workability deteriorates. Further, Cr improves the corrosion resistance of the magnetic wire. If the content exceeds 9% by weight, the magnetic flux density of the magnetic wire decreases, and the heat generated for snow melting cannot be obtained.

According to a third aspect of the present invention, there is provided a snow-melting electric wire obtained by coating a magnetic wire having the above alloy composition with an aluminum material and winding the aluminum-coated magnetic wire around an aluminum overhead electric wire so that tensile stress remains. . The aluminum material is coated to prevent electric corrosion between the aluminum overhead electric wires. Also, the reason why the tensile stress remains in the magnetic wire is that the magnetostriction of the magnetic wire of the present invention is positive, and when the tensile stress remains in the magnetic wire having a positive magnetostriction, the magnetic properties are improved and the calorific value is improved. That's why. To maintain tensile stress in the magnetic wire during power transmission, the magnetic wire can be welded, brazed, or mechanically fixed to the overhead electric wire at a temperature equal to or lower than room temperature. The method of winding and fixing to an overhead electric wire can greatly improve the calorific value. Welding, brazing, or mechanical fixing may be performed only at both ends of the magnetic wire. By fixing the magnetic wire to the overhead electric wire, the displacement of the magnetic wire when passing through the wheel can be prevented without using a spacer.

According to a fourth aspect of the present invention, an aluminum wire is used as a spacer in a gap between the spirally wound magnetic wires so as to be wound below the height of the metal-coated magnetic wire. It is a snowmelt electric wire of the above-mentioned invention. Since there is no displacement of the magnetic wire when the snow melting electric wire passes through the wheel, and since the magnetic wire protrudes from the aluminum wire, an excessive temperature rise is prevented even at the time of large current transmission due to the fin cooling effect of the magnetic wire.

The invention according to claim 5 is characterized in that an aluminum wire is used as a spacer in the gap between the spirally wound magnetic wires so as to be wound at a height of not more than half the height of the metal-coated magnetic wire. The snow melting electric wire according to any one of claims 1 to 4. Since the aluminum-coated magnetic wire projects more than half of its diameter from the spacer (aluminum-wound body), the fin cooling effect is increased, and the allowable current at the maximum operating temperature can be increased.

According to a sixth aspect of the present invention, the cross section of the magnetic wire is rectangular, square or fan-shaped.
A snowmelt electric wire according to claim 5. By making the cross-sectional shape of the magnetic wire into a rectangular, square or sector shape, the contact area with the overhead wire becomes larger than that of a wire with a circular cross section,
The snow melting effect can be enhanced.

According to a seventh aspect of the present invention, there is provided the snow melting electric wire according to any one of the first to sixth aspects, wherein a magnetic wire or a magnetic wire and a spacer are wound only on a required portion of the overhead electric wire. Since the magnetic wire is wound only where snowmelt measures are required, not only energy loss but also installation cost can be reduced.

[0020]

According to the first aspect of the present invention, the magnetic wire coated with aluminum is spirally wound on the outermost layer of the aluminum overhead electric wire, and the aluminum wire is inserted into the gap between the spirally wound magnetic wires. Since the aluminum-coated magnetic wire is wound as a spacer for keeping the gap constant, the magnetic wire does not shift when passing through a wheel while the wire is being wired, and a predetermined good snow melting effect can be obtained. Also, the aluminum coated magnetic wire is
Since more than half of the diameter is projected from the aluminum wire wound body for the spacer, it is cooled by its own fin cooling effect and the temperature rise due to eddy current heat generation is prevented. Since the magnetic wire is cooled by the fin cooling effect as described above, a material having a high Curie temperature can be used as the magnetic wire, and therefore, a material having a high magnetic flux density in a low magnetic field can be selected as the magnetic wire. The fin cooling effect can be obtained by protruding the magnetic wire from the aluminum wire wound body for spacer even a little. Further, since the magnetic wire is coated with the aluminum material, the magnetic wire does not cause electrolytic corrosion with the overhead electric wire. According to the second aspect of the present invention, the magnetic wire is coated with a zinc material, and the same effect of preventing electrolytic corrosion as in the case of coating an aluminum material can be obtained. In addition to pure zinc, a zinc alloy can be applied to the zinc material.

The magnetic wire used in the invention of claim 3 has a positive magnetostriction, and this magnetic wire is provided on the outermost layer of the aluminum overhead electric wire.
Since the wire is spirally wound so that the tensile stress remains during power transmission, the magnetic properties of the magnetic wire are improved, and the snow melting effect is improved. Since the magnetic wire is covered with the aluminum material, electric corrosion with the overhead electric wire is prevented. When the magnetic wire is fixed to the overhead electric wire so that a tensile stress remains in the magnetic wire during power transmission, the displacement of the magnetic wire when passing through the wheel is prevented. The displacement of the magnetic wire when passing through the wheel is also prevented by interposing a spacer between the magnetic wires. By projecting the magnetic wire from the spacer, the magnetic wire can have a fin cooling effect. By projecting at least half the height of the magnetic wire from the spacer, the fin cooling effect of the magnetic wire can be further enhanced.

As a common feature of the snow melting electric wires of the first to third aspects, the magnetic wire can be brought into close contact with the overhead electric wire by making the cross section of the magnetic wire a rectangle, a square, or a fan. In addition, by wrapping the magnetic wire only at a place where a measure against snow melting is required, energy loss and reduction of installation cost can be reduced.

[0023]

The present invention will be described below in detail with reference to examples. (Example 1) A magnetic wire is wound around an overhead electric wire with an aluminum wire interposed between the magnetic wires as a spacer.
A snowmelt electric wire was manufactured. The XTACI is an overhead wire that is made of 7 layers of 4.4mmφ Invar wire coated with 0.45mm of aluminum and 3 layers of special heat-resistant aluminum alloy wire with a fan-shaped cross section.
A transmission line having an R650 mm ² (invar wire cross-sectional area of 106 mm ² , special heat-resistant aluminum alloy wire cross-sectional area of 653.4 mm ² , outer diameter of 33.150 mmφ) was used. This transmission line can withstand a load even if a 1 kg magnetic wire is wound per 1 m of the transmission line. The magnetic wire rod wound around the transmission line includes pure iron and Fe-Ni alloy 7 shown in Table 1.
One kind of Fe—Ni—Cr—Si alloy was used. Pure aluminum, aluminum alloy, or zinc for the nine types of magnetic wires,
Coating was carried out by any one of a hot dip method, an electroplating method and an aluminum pipe coating method. In the aluminum pipe deposition method, a 10mmφ magnetic wire is coated with an aluminum pipe, and the diameter of the magnetic wire is
Drawing was performed to 2.6 mmφ. The magnetic wire coated with the aluminum material or the like was spirally wound around the above-described invar-reinforced power transmission line via a spacer. A special heat-resistant aluminum strip or wire was used for the spacer. The outer diameter of the aluminum conductor around which the spacer of the snow melting electric wire was wound was about 34.3 mmφ.

An embodiment of the obtained snow melting electric wire will be specifically described with reference to the drawings. 1A and 1B are a cross-sectional view and a side view, respectively, showing an embodiment of a snow melting electric wire according to the present invention. On the outer periphery of the Invar twisted wire 3 of the Invar wire 2 coated with the Al layer 1,
An overhead electric wire 5 is formed by twisting a special heat-resistant aluminum alloy wire 4 having a sectoral cross section into three layers, and a magnetic wire 6 and spacers 7 are twisted around the outer periphery of the overhead electric wire 5 at a ratio of 1: 5. The magnetic wire 6 is wound so as to protrude from the spacer 7 and the fin cooling effect is maintained. The magnetic wire 6 is coated with an Al material layer 8 to prevent electrolytic corrosion.

Next, the method for producing the magnetic wire is described as Fe-N
Description will be made by taking an i-Cr-Si alloy as an example. First, 99.9% pure electrolytic iron, 99.9% electrolytic nickel, 99% electrolytic chromium, and 99.999% silicon were used as raw materials, each of which was blended in a predetermined amount, vacuum melted and cast to form an ingot. . Next, after soaking this ingot at 950 ° C for 48 hours, hot rolling, drawing, and wire drawing were sequentially performed to obtain 2.6
mmφ wire rod. Next, this was annealed in hydrogen at 1050 ° C. for 3 hours and cooled in a furnace. 2.0 for other materials,
2.6 or 4.0mmφ wire was processed. The magnetic properties of these magnetic wires were measured. Among the magnetic properties, the saturation magnetic flux density and the Curie temperature were measured on a 2.6 mmφ × 5 mm sample under a magnetic field intensity of 10 Oe using a vibrating sample magnetometer.
The magnetic flux density is set at the center of the excitation coil around which 327 turns of 0.65mmφ enameled wire are wound, and a 25-turn magnetic flux detection coil is placed.A 2.6mmφ × 1000mm magnetic wire is placed in this detection coil, and B -Measured with an H curve tracer. The magnetic field strength was changed to 40, 20, and 10 Oe. The results are shown in Table 1 together with the specific resistance at 0 ° C.

[0026]

[Table 1]

As apparent from Table 1, the magnetic flux densities B ₁₀ at 10 Oe of the alloys a to e for the magnetic wire used in the snow-melting wire of the present invention are different from those of the comparative examples (No. f, g, h, i). It can be seen that the difference is small compared with the magnetic flux densities B ₂₀ and B ₄₀ at 20 Oe and 40 Oe of the alloy for a magnetic wire according to the present invention, and the magnetic flux density saturation characteristics are good. B ₁₀ of the present invention is nearly twice higher when compared to the flux density of the alloy h used in the conventional snow-melting wire.

The corrosion resistance of the snow-melted electric wire wound with the magnetic wire was examined by performing a salt spray test. In addition, the calorific value per m of the transmission line when 91 A was supplied to the snow melting electric wire (wire surface magnetic field was 10 Oe), and the wire temperature when the maximum allowable current was 2300 A was measured. Table 2 shows the results.

[0029]

[Table 2]

As is clear from Table 2, the sample of the present invention (N
The corrosion resistance of o.1 to 13) is limited to 20
When the thickness is more than μm, it can withstand a salt spray test for 3000 hours. Even at 10 μm, it can withstand 2,000 hours of salt spray, and there is no practical problem. The one using a magnetic wire rod electroplated with an Al-20 wt% Mn alloy (No. 4) also showed the same high corrosion resistance as when coated with pure aluminum.

The calorific value of the product of the present invention (Nos. 1 to 14) when the current of 91 A is turned on is considerably higher than that of the comparative product (Nos. 21 to 23). Despite the fact that the saturation magnetic flux density of the magnetic alloys a to e used in the snow melting wire of the present invention is 5000 G or more lower than that of the pure iron i, the calorific value of the snow melting wire of the present invention (No. 1 to 14) is The reason why the magnetic flux density is higher than that of the snow melting wire (No. 24) using a magnetic wire is that B ₁₀ (magnetic flux density at 10 Oe) is high. Ni content is 50wt%
In this case, the amount of heat generated when the current is supplied to 91A is maximized. Ni is 40wt
% Or 60 wt% (Nos. 1 and 9) slightly reduced the calorific value, but the calorific value required for partial snow melting was obtained. In addition, 5mm per hour
The required calorific value for complete snowmelt is 15.9 w / m, and the calorific value required for partial snowmelt is 12.5 w / m.

The electric wire temperature when a current of 2300 A is applied to the sample of the present invention is as follows:
The temperature was lower than the temperature (No. 25, 230 ° C) without winding the magnetic wire. Each of the magnetic wires used in the present invention has a high Ni content and a high Curie temperature, and generates a considerable amount of heat when a current of 2300 A is supplied. However, the heat generation was suppressed by its own fin cooling effect. From this, it can be seen that even if a magnetic wire having a low Curie temperature is not used, the increase in the wire temperature can be sufficiently suppressed under the maximum allowable current flow by giving the magnetic wire a fin cooling effect. Among the products of the present invention, the wire temperature of No. 7 increased relatively to 220 ° C. This is because the fin cooling effect of the magnetic wire was slightly reduced because the thickness of the spacer strip was as large as 1.0 mmφ.
No.12 uses a 1.0mmφ wire for the spacer.
Again, the temperature was relatively high at 218 ° C. Because the wire (No. 12) has more gaps, heat easily escaped and the temperature was slightly lower than that of the strip (No. 7).

The corrosion resistance of the comparative example product was less than 2000 hours in salt water spray and was not plated (No. 16).
Corrosion was observed in the thinner one (μm) (No. 17).

The heat value of the comparative example when the current was 91 A was No. 15,
18,20 to 24,25 were low. This is because, as is apparent from Table 1, since it is low flux density B ₁₀ of a low magnetic field of the magnetic alloy used. No. 15 uses a magnetic alloy a having a low Ni content of 36%, and this alloy a has a lower B content than B ₄₀ and B _20.
10 rapidly decreases, and the amount of heat generated when 91 A is energized is about half that of the snow melting electric wires (Nos. 1 to 13) of the present invention. Ni content is 60%
The heat value of No. 20 using the magnetic alloy b exceeding 12.5 W / m is less than 12.5 w / m, which is sufficient to partially obtain the snow melting effect, and is not suitable for a snow melting wire.

The wire temperature of the comparative example product at the time of 2300 A power supply was N
o.19,24 exceeded the electric wire temperature of No.25 which does not wind magnetic wire. In No. 19, the thickness of the spacer was more than half of the diameter of the magnetic wire, and the fin cooling effect of the magnetic wire was not sufficiently obtained, and the temperature rose to 232 ° C. Nos. 2 and 4 use pure iron with a high Curie temperature, and the temperature at the allowable current is higher than the temperature rise of the electric wire (No. 25) without the magnetic wire wound. No.8
Means that the content of Ni exceeds 60% and the Curie temperature is 600 ℃
As described above, the temperature does not rise much. This is because the heat dissipated by the fin cooling effect of the magnetic wire is larger than the heat generated by the magnetic wire at the allowable current.

Next, the coating thickness of the aluminum material coated on the magnetic wire will be described. No. 21 to 23 are snow melting electric wires used in conventional snow melting electric wires, in which the specific resistance is 120 μΩcm and magnetic alloy h is coated with aluminum in various thicknesses. Is maximum at 150 μm. On the other hand, Fe-50wt% Ni alloy with low specific resistance of 32μΩcm
No.17,5,6,13,18 wire with magnetic wire of 5,10,20,60 and 80μm electroplated aluminum around the magnetic wire of No.17,5,6,13,18
Calorific value is maximum at 20μm (No.6) and plating thickness is 80
When the thickness is increased to μm, a calorific value capable of melting snow cannot be obtained.
When the plating thickness is large, polishing is required after plating, which increases the cost. Therefore, the optimum plating thickness is around 20 μm.

Looking at the effect of the method of coating the magnetic wire with aluminum on the calorific value at the time of conducting 91 A, the former calorific value is smaller than that of No. 3 (hot-dip plating) and No. 6 (electroplating). It is considered that hot-dip plating of aluminum lowers the magnetic properties of the magnetic wire. No.10 (2.0mmφ), No.6
Looking at (2.6 mmφ) and No. 11 (4.0 mmφ), there is a tendency that the larger the wire diameter, the larger the calorific value.

Example 2 A magnetic wire having the alloy composition shown in Table 3 was produced by the following method. 99.9% pure electrolytic iron,
99.9% electrolytic nickel, 99.5% cobalt, 99.9%
9% of aluminum, 99% of electrolytic chromium, 99.999% of silicon, and 99.7% of vanadium were used as raw materials, each of which was blended in a predetermined amount, melted under vacuum, and cast to form an ingot. Next, the ingot was soaked at 950 ° C. for 48 hours, and then subjected to hot rolling, drawing, and wire drawing in order to obtain a 2.6 mmφ wire. Next, this was annealed in hydrogen at 1050 ° C. for 3 hours and cooled in a furnace. The magnetic properties of the obtained magnetic wire were measured. Among the magnetic properties, the saturation magnetic flux density and Curie temperature are 2.6 mmφ ×
A 5 mm sample was measured under a magnetic field strength of 10 kOe using a vibrating sample magnetometer. The magnetic flux density is set at the center of the excitation coil around which 327 turns of 0.65mmφ enameled wire are wound, and a 25-turn magnetic flux detection coil is placed.A 2.6mmφ × 1000mm magnetic wire is placed in this detection coil, and B -Measured with an H curve tracer. The magnetic field strength was changed to 40 and 10 Oe.
The results are shown in Table 3 together with the specific resistance at 0 ° C.

[0039]

[Table 3]

As is clear from Table 3, the magnetic alloy of the present invention has a high or low B ₁₀ (magnetic flux density at 10 Oe). Alloy No.k, l, m, o, p, t are less B ₁₀ than alloy No.h conventionally used.

The magnetic wire shown in Table 3 was wound and fixed by applying tension to the overhead electric wire, thereby leaving a tensile stress in the magnetic wire to produce a snow melting electric wire. The XTA consists of 7 strands of 4.4 mmφ invar wire coated with aluminum and 3 layers of special heat-resistant aluminum alloy wire with a fan-shaped cross section.
CIR 650mm ² (Invar wire cross-sectional area 106mm ² , special heat-resistant aluminum alloy wire cross-sectional area 653.4mm ² , outer diameter 33.150mmφ) The 4.4mmφ invar line of 5.3mmφ thickened to 5.3mmφ, and the transmission line 1m
Even if a magnetic wire rod of 1 kg / wound is wound, it can withstand a load. A product in which an aluminum wire was interposed as a spacer between magnetic wires was also manufactured. Pure Al is used for the magnetic wire,
Coating was carried out by any one of a hot dip method, an electroplating method and an aluminum pipe coating method. In the aluminum pipe deposition method, a 10 mmφ magnetic wire is coated with an Al pipe, and the diameter of the magnetic wire is 2.6 mm.
The wire was drawn to have a diameter of mmφ. A special heat-resistant aluminum strip or wire was used for the spacer. The outer diameter of the aluminum conductor around which the spacer of the snow melting electric wire was wound was about 34.3 mmφ.

Although the shape of the obtained snow melting electric wire is such that the magnetic wire is fixed to the overhead electric wire and no spacer is used, a cross sectional view and a side view are shown in FIGS. An overhead electric wire 5 is formed by twisting a special heat-resistant aluminum alloy wire 4 having a fan-shaped cross section into three layers around the outer periphery of the Invar stranded wire 3 of the Invar wire 2 covered with the Al layer 1, and a magnetic wire material is provided around the outer periphery of the overhead electric wire 5. 6 are wound. The magnetic wire 6 is coated with an Al material layer 8 to prevent electrolytic corrosion. The overhead electric wire 5 and the magnetic wire 6 are seam-welded. The shape using the spacer is the same as that in FIG.

A salt spray test was performed on the snow-melted electric wire wound with the magnetic wire to examine corrosion resistance. In addition, the calorific value per m of the transmission line when 91 A was supplied to the snow melting electric wire (wire surface magnetic field was 10 Oe), and the wire temperature when the maximum allowable current was 2300 A was measured. The results are shown in Tables 4 and 5.

[0044]

[Table 4]

[0045]

[Table 5]

As is clear from Table 4, the product of the present invention (No.
In Nos. 26 to 45), the aluminum wire of the magnetic wire had a thickness of 20 μm or more, and thus could withstand a 3000-hour salt spray test. Product of the present invention
(Nos. 26 to 45) all have a higher calorific value when the current of 91 A is applied than the comparative example (Nos. 43 to 61). As can be seen from the electric wires Nos. 34 to 36, the larger the residual tensile stress is, the larger the calorific value increases. Especially B ₁₀ is low alloy k, l, with magnetic wires of m, the tensile heating value of comparative examples 47, 48, 49 without leaving a stress is low, snow melting wire of the present invention obtained by the residual tensile stress (No .
27,28,29) are significantly improved. In the other magnetic alloys of the present invention, the calorific value is also improved by applying tension. In addition, the calorific value required for complete snow melting at a snowfall of 5 mm per hour (precipitation conversion value) is 15.9 w / m, and the calorific value required for partial snow melting is 12.5 w / m.

The electric wire temperature at the time of energizing 2300 A of the product of the present invention is
The temperature was lower than the temperature (No.61, 230 ℃) without winding the magnetic wire. The magnetic wire used in the present invention has a Curie temperature higher than 230 ° C. except for h, and generates a considerable amount of heat when a current of 2300 A is supplied. However, the heat generation was suppressed by its own fin cooling effect. From this, it can be seen that even if a magnetic wire having a low Curie temperature is not used, the increase in the wire temperature can be sufficiently suppressed under the maximum allowable current flow by giving the magnetic wire a fin cooling effect. twenty three
00A The wire temperature during energization is
It is relatively low at 213 ° C compared to o.33,34. In the case where the spacer is used, the temperature rise of No. 33, which is thick, is large.

No. 31 and No. 32, in which an iron n of an Fe-50% Ni alloy was substituted with 3% Cr and 1% Si and having tensile stress remaining, can obtain a complete snow melting effect. Table 5 when no tensile stress is left
No.56 and 57, no partial snowmelt effect can be obtained. The wire temperature rise of alloy n is relatively low, because the Curie temperature is low.

In the comparative example, a snow-melted electric wire tensioned (electric wire No. 5
8,59), the amount of Ni deviated from the Ni content according to the second aspect of the present invention, so that a calorific value for obtaining a sufficient snow-melting effect could not be obtained. In addition, the calorific value of the snow melting electric wire (electric wire No. 60) in which the tension was applied to the magnetic wire of pure iron decreased, because the magnetostriction of pure iron was negative.

[0050]

As described above, the snow-melting electric wire of the present invention is obtained by spirally winding a magnetic wire around an overhead electric wire, and uses a magnetic wire that generates a large amount of eddy current heat in a low magnetic field. It has a high snow melting effect even when a low current is applied.It also prevents the magnetic wire from shifting when passing through a wheel with a spacer interposed between the magnetic wires, and also prevents excessive heat generation in a high magnetic field of the magnetic wire. It is projected from the spacer and suppressed by its fin cooling effect, and the magnetic wire is coated with aluminum to prevent electrolytic corrosion with the overhead electric wire. In addition, the magnetic wire is wound around the overhead electric wire with tensile stress remaining to improve eddy current heat generation in a low magnetic field, and the tensile stress is further retained by fixing the magnetic wire to the overhead wire and passing through a metal wheel. The displacement of the magnetic wire at the time is prevented. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is a cross sectional view and a side view showing an embodiment of a snow melting electric wire according to the present invention.

FIG. 2 is a cross sectional view and a side view showing another embodiment of the snow melting electric wire of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Al coating layer 2 Invar wire 3 Twisted wire of aluminum coating invar wire 4 Special heat-resistant aluminum alloy wire of sector shape 5 Overhead electric wire 6 Magnetic wire 7 Spacer 8 Al material layer

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-193516 (JP, A) JP-A-58-223211 (JP, A) JP-A-59-216415 (JP, A) JP-A-61-216 203511 (JP, A) JP-A-1-95407 (JP, A) JP-A-2-111215 (JP, A) JP-B-42-13893 (JP, B1) JP-B-1-35574 (JP, B2) Japanese Utility Model 51-19167 (JP, Y2) Japanese Utility Model 1-12338 (JP, Y2) Japanese Utility Model 1-34502 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02G 7/16

Claims (7)

(57) [Claims] 1. A snow melting electric wire in which a magnetic wire is spirally wound around the outermost layer of an aluminum overhead electric wire, wherein the magnetic wire is
An alloy magnetic wire comprising 40 to 60 wt% of Ni and the balance of Fe, wherein the magnetic wire is coated with an aluminum material to a thickness of 10 to 60 μm, and the aluminum-coated magnetic wire wound in a spiral shape. In the gap, an aluminum wire is wound as a spacer for keeping the interval between the aluminum-coated magnetic wires constant, and the aluminum-coated magnetic wire protrudes from the aluminum wire wound body. Snow melting electric wire. 2. A snow melting electric wire in which a magnetic wire is spirally wound around the outermost layer of an aluminum overhead electric wire, wherein the magnetic wire is
An alloy magnetic wire comprising 40 to 60% by weight of Ni and the balance of Fe, wherein the magnetic wire is coated with a zinc material to a thickness of 10 to 60 μm, and the aluminum-coated magnetic wire wound spirally. In the gap, an aluminum wire is wound as a spacer for keeping the interval between the aluminum-coated magnetic wires constant, and the aluminum-coated magnetic wire protrudes from the aluminum wire wound body. Snow melting electric wire. 3. A snow melting electric wire in which a magnetic wire is spirally wound around the outermost layer of an aluminum overhead electric wire, wherein the magnetic wire is
Ni is 3 to 28 wt% or 35 to 65 wt%, Co is 0 to less than 10 wt%, Al is 0 to 9 wt%, Si is 0 to 7.5 wt%, and V is 0 to 0 wt%.
Alloy containing 4 wt%, 0 to 9 wt% Cr and the balance Fe, or 3 to 60 wt% Ni, 10 to 65 wt% Co, A
l is 0 to 9 wt%, Si is 0 to 7.5 wt%, and V is 0 to 4 wt%.
%, 0 to 9 wt% of Cr and the balance of Fe, and a metal of Al, Al alloy, Zn or Zn alloy having a thickness of 10 to 120 μm is formed on the surface of the magnetic wire. A snow-melted electric wire which is covered and wound around the metal-coated magnetic wire so that tensile stress remains during power transmission. 4. The snow-melting electric wire according to claim 3, wherein an aluminum wire is used as a spacer in a space between the spirally wound magnetic wires so as to be wound below the height of the metal-coated magnetic wire. 5. The method according to claim 1, wherein an aluminum wire is used as a spacer in the gap between the spirally wound magnetic wires so as to be wound at a height of not more than half the height of the metal-coated magnetic wire. The snowmelt electric wire according to claim 4. 6. The snow melting electric wire according to claim 1, wherein the magnetic wire has a rectangular, square or fan-shaped cross section. 7. The snow melting electric wire according to claim 1, wherein a magnetic wire or a magnetic wire and a spacer are wound around only a required portion of the overhead electric wire.