JPS6258848A - Insulating coil - Google Patents

Abstract

PURPOSE:To prevent corona-proof material or core from being abraded due to electromagnetic vibration or the like, by winding up and hardening a cloth tape coated with silicon carbide paint up to the desired length of a coil end to form a silicon carbide layer. CONSTITUTION:On the insulation 2 of a coil formed on a coil conductor 1, the tape of glass cloth coated with silicon carbide paint up to the desired length of a coil end section B from a position separated slightly from a core slot inserting section A is wound up, to set a hardened silicon carbide layer 3. After that, cloth tape coated with low resistance paint obtainable from varnish mixed with carbon, with the base cloth of aramid fiber cloth on the surface of the coil insulation is wound up on the core slot inserting section, a section protruded slightly from the slot, and the end section of the silicon carbide layer 3, to form a hardened low resistance layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an insulated wire for a rotating electrical machine provided with a corona prevention device.

[Technical background of the invention and its problems]

Conventionally, in order to prevent corona from entering the core slot of the insulated wire ring of single-rotation electric machines and the coil end, asbestos tape was wrapped around the insulating surface of the wire ring at the slot portion and the portion that slightly protruded from the slot portion. After turning, a low resistance (102 to 104 ohm) paint was applied and cured, and asbestos tape was wound around the insulating surface at the end.

However, as it has become clear that asbestos is harmful to the lungs and respiratory system, there is a growing demand for ways to prevent coronavirus without using asbestos. However, asbestos is highly flexible and has excellent properties when wrapped in a single wrap, and has high heat resistance, so it is less susceptible to deterioration due to surface discharge, and because it is an aggregate of fine fibers, it has excellent retention of paint and resin. Are better. Furthermore, an important point for the corona preventive material in the slot portion is that the corona preventive material itself or the core does not wear out due to friction with the iron core due to electromagnetic vibration or the like.

Therefore, no material with such characteristics that can replace asbestos has been found.

[Purpose of the invention]

The present invention prevents the corona prevention material or the iron core from wearing out due to electromagnetic vibration, etc., has excellent retention of varnishes such as low-resistance paints, has good workability when wrapping, and has no problems with overlaying corona. The object is to provide an insulated wire ring having a prevention device.

[Summary of the invention]

In the present invention, a low-resistance tape coated with a low-resistance paint using an aramid fiber woven fabric as a base fabric is wound and cured on the insulating surface of the coil at the part inserted into the core slot and the part slightly protruding from the slot. By forming a low resistance layer and a hardened silicon carbide layer connected to this low resistance layer by winding a woven fabric tape coated with silicon carbide paint to the desired length of the coil end, a corona prevention device is formed. It achieves the above objectives by replacing conventional asbestos.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, the main insulation (2) is formed on the wire ring conductor (2) by a predetermined process. A silicon carbide layer (2) is provided on this coil insulation (2) from a position slightly in front of the core slot insertion p (A) to a desired length of the coil end (B). This silicon carbide layer ■ is made by wrapping a semi-cured silicon carbide tape around a woven glass cloth coated with a paint mainly composed of silicon carbide and thermosetting resins such as epoxy, polybutadiene, and polyimide.
It is formed by curing. Next, aramid fiber woven fabric is used as a base fabric on the surface of the wire insulation, and epoxy or other A woven fabric tape coated with a low-resistance paint obtained by mixing carbon with fibers is wound around it, forming a hardened low-resistance layer.

Next, the effect will be explained.

The abrasion resistance, which is the most important issue of the corona prevention device in the slot part (A), is determined by comparing A when conventional asbestos is used as the base fabric of the same thickness, B when using glass woven fabric, and B when using the above example. Regarding C when using aramid woven fabric, JIS
Table 1 shows the number of reciprocating strokes required to abrade the anti-corona layer until it penetrates, as measured using a C3003 reciprocating abrasion tester.

Table 1 As can be seen from Table 1, when glass is used as the base fabric, it is subject to severe abrasion and the iron core is easily damaged by abraded dust, whereas in the case of aramid, there is less abrasion than asbestos.
It turns out that the iron core is hard to damage. In addition, aramid woven fabric is harmless in terms of occupational hygiene, has high heat resistance, and is resistant to electrical discharge.
In addition, since it is made of intertwined fine fibers, it is highly flexible and has excellent winding workability, and also has excellent resin retention properties, forming a solid corona prevention layer on the insulating surface. I can do it.

The embodiment shown in Fig. 3 has a silicon carbide layer (2) partially superimposed on the low resistance layer, and the embodiment shown in Fig. 4 has a carbon-containing varnish applied to a glass woven fabric and dried. The obtained low-resistance tape (2) is wound in advance on the surface of the insulating layer (2) below the contact area of the silicon carbide tape layer (2) and the low-resistance layer.

Even if these methods are used, the only difference is the manufacturing process, and the first
The same effects as those of the embodiment shown in FIG. 2 and FIG. 2 can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the corona prevention material or the iron core does not wear out due to electromagnetic vibration, etc., and it has excellent retention of varnishes such as low-resistance paints, and winding is easy and labor-intensive. It is possible to provide an insulated wire ring having a corona prevention device that does not cause sanitary problems.

[Brief explanation of drawings]

Fig. 1 is a top view showing one embodiment of the insulated wire ring of the present invention, Fig. 2 is an enlarged sectional view of the main part of Fig. 1, and Figs. 3 and 4 are main parts of other different embodiments. FIG. 1... Wire shaft conductor, 2... Wire ring insulation,
3... Silicon carbide layer, 4... Low resistance layer, 5
...Low resistance tape, A...Slot part,
B...Coil end part. Agent Patent Attorney Mr. Inoue Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) Low-resistance tape coated with low-resistance paint, with aramid fiber woven fabric as the base fabric, is wrapped and hardened on the insulating surface of the wire at the part inserted into the core slot and the part slightly protruding from the slot. A corona prevention device is formed by forming a silicon carbide layer connected to this low resistance layer and hardened by winding a woven fabric tape coated with silicon carbide paint to the desired length of the coil end. Insulated wire ring. (2) The insulated coil according to claim 1, wherein the low resistance layer and the silicon carbide layer are connected by overlapping their ends.