JPS586055A - Molded coil - Google Patents

Abstract

PURPOSE:To obtain a coil having small dielectric tangent by grounding a low resistance corona shield layer of a coil at a position isolated for a lead wire, thereby sufficiently reducing the resistance value of the layer as compared with a main insulating layer. CONSTITUTION:A low resistance corona shield layer 4 is provided on the outer periphery of a main insulating layer 3, and a current flowing path 20 is formed between the layer 4 and the ground at the position isolated from a pair of lead wires 9a, 9b with a molded coil 1 molded integrally with a molding material as a whole, thereby grounding the shield layer. In this manner, the dielectric tangent of the coil 1 utilized for a linear motor ground installation coil for a vehicle can be reduced, thereby decreasing a dielectric loss.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molded coil, and particularly to a molded coil mainly used outdoors, such as a ground-mounted coil for a linear motor for a vehicle.

As is well known, the ground coil of a vehicle linear motor is a coil that propels a vehicle attached to a track laid on the ground. Since it is mounted on the track and used in this way, it is exposed to all weather conditions and is also affected by electromagnetic forces generated by on-vehicle coils.

For this reason, a molded coil whose exterior is robustly molded with a molding material is generally used to withstand these harsh conditions.

A conventional example of such a molded coil is shown in FIG. The molded coil 1 includes a main insulating layer 3 mainly made of mica, which is formed by winding a coil conductor 2 into a rectangular shape with multiple turns.
A coil body formed by the n* low-resistance corona shield layer 4 wound around the outside of the main insulating layer 3 is molded with a molding material having excellent weather resistance, water resistance, 1 mechanical strength, etc. Explode.

Sheet molding compound, resin concrete, etc. are used as the molding material, and the exterior 5, ribs 6, and exterior 7 of the outlet portion of the coil body are molded together at the same time. A mounting hole 8 is provided in the lip 6, and a bolt is passed through this mounting hole 8 to fix it to the concrete track. In the figure, 93 and 9b are the Hiji line.

A sheet chilling compound is a sheet made by mixing short glass fibers, powder fibres, catalysts, internal molding agents, pigments, thickeners, etc. into a resin such as unsaturated polyester resin and holding it in a semi-cured state. −
No. 1 is a method in which gravel and sand are mixed into a thermosetting resin such as an unsaturated polyester resin.

Since such a molded coil 1 is larger than the coil size of a general rotating electrical machine, the resistance Rs of the low resistance corona shield layer 4 is larger than that of the main insulating layer 3, as shown in FIGS. 2 and 3. It is too large to be ignored compared to the equivalent parallel resistance Rp, and has the drawback that the value of the dielectric loss tangent becomes large when the current in phase with the current of the equivalent parallel resistance Rp of the main insulating layer 3 is added. As the value of the dielectric loss tangent increases, the deterioration of the Simold coil 1, which has a large dielectric loss, accelerates. This is particularly problematic because the higher the voltage, the greater the influence of the dielectric loss tangent. Note that FIG. 3 shows the main insulating layer 3 of FIG.
and the equivalent circuit of the low-resistance corona shield layer 4, and CP is the equivalent parallel capacitance of the main insulating layer 3.

In view of the above points, the present invention has been developed f', and its object is to provide a molded coil with a small dielectric loss tangent.

That is, the present invention is characterized in that a current-carrying path is provided between the low-resistance corona shield layer located NFC away from the lead wire and the ground, and the low-resistance corona shield layer is grounded.

The present invention will be explained below based on the illustrated embodiments. FIG. 4 shows an embodiment of the present invention. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, it is the Hiji Line 9a.

At the surface of the low-resistance corona shield layer 4 at a position as far away from 9b as possible, that is, at a point A in the center of the long side of the rectangular molded coil 1 opposite to the long side where the sunrise lines 9a and 9b are provided. A bare copper wire is wound several times on top of the conductive paint to form a ground terminal 1o.

This ground terminal 10 and a grounded lead wire 11 were connected to form a current conducting path 20 between the low resistance corona shield layer 4 and the ground, so that the low resistance corona shield layer 4 was grounded. After forming the ground terminal 1o, the outer periphery of the low resistance corona shield layer 4 is molded with a molding material. In this way, the Hiji Line 9a.

By providing a grounding terminal 10 on the surface of the low resistance corona shield layer 4 at a position as far away from 9b as possible for grounding, the resistance value of the low resistance corona shield layer 4 is compared to the equivalent parallel resistance of the main insulating layer 3. If ignored, the value of the dielectric loss tangent will become smaller.

FIG. 5 shows the results of examining the voltage characteristics of the dielectric voltage contact in the above embodiments. In the figure, in Example A, a ground terminal is provided on the surface of the low-resistance corona shield layer at the center of the long side of the rectangular molded coil on which the sunrise wire is provided. Example B is a rectangular molded coil that is grounded by providing grounding terminals at two locations: the surface opening of the low-resistance corona shield layer 4 in the center of both short sides, and the C part. (See FIG. 4) In Example C, grounding terminals are provided at three locations, A, B, and C, for grounding. Comparative Example D (A) Aluminum foil was wound around the entire surface of the wound low-resistance corona shield layer to serve as an electrode. Comparative Example E was simply formed by winding a conventional low-resistance corona shield layer. .In Examples A, B, and C, the dielectric loss tangent value is about 1/3 smaller than that of Comparative Example E, and is a comparative example in which an aluminum foil electrode is wound over the entire surface of the low-resistance corona shield layer. Embodiment A is advantageous in terms of the number of man-hours required for providing the grounding terminal, and is sufficiently satisfactory in terms of characteristics.

As described above, in the present invention, a current-carrying path is provided between the low-resistance corona shield layer located at a distance from the lead wire and the ground, and the low-resistance corona shield layer is grounded.
The resistance value of the low-resistance corona shield layer becomes negligibly small compared to the equivalent parallel resistance of the main insulating layer, and the dielectric loss tangent becomes small, making it possible to obtain a molded coil with a small dielectric loss tangent.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing a conventional molded coil;
2 is a cross-sectional plan view of FIG. 1, FIG. 3 is an equinodal circuit of the main insulating layer and low-resistance corona shield layer of FIG. 2, and FIG. 4 is a cross-sectional plane of an embodiment of the molded coil of the present invention. Figure, 5th
The figure is a comparative characteristic diagram showing the relationship between the dielectric loss tangent and the applied voltage of the molded coils of the present example and the comparative example. 1°° molded coil, 3°° main insulation layer, 4...
Low resistance corona shield layer, 9a, 9b... Lead wire, 1
o...Grounding terminal, 11...Grounding lead wire, 2
o... energized path. 1st (B 72 Figure 3 Figure 4L Figure 5I21

Claims (1)

[Claims] 1. A main insulating layer provided on a coil conductor wound in a rectangular shape, a low resistance corona shield layer wound around this main insulating layer, and a low resistance corona shield layer wound around the main insulating layer; In a molded coil having a Hiji wire f'L and a Hiji wire drawn out from the winding start and end of a coil conductor, respectively, and the whole of these wires being molded with a molding material, the distance between the Hiji wire and the winding wire is t. A molded coil characterized in that a conductive path is provided between the low-resistance corona shield layer and the ground at a position such that the low-resistance corona shield layer is grounded.2. The molded coil according to claim 1, wherein the molded coil is formed by a grounding terminal provided at at least one location on the corona shield layer and a grounding lead wire.