JPS5814670Y2 - Suifuushikisuichiyudendouki - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a water-sealed submersible electric motor using a new electric wire.

As shown in FIG. 1, a conventional electric wire for an underwater electric motor is first coated with a synthetic resin (for example, formal, polyester,
Epoxy, etc.) was applied to a thickness of 0.025 mm to 0.05 mm, and a polyethylene or chemically crosslinked polyethylene film was formed on top of the insulating layer 3.

However, since polyethylene has a low dielectric constant and a high volume resistivity, if some foreign matter or water enters, this intruder acts as a needle-shaped electrode under an electric field, forming a local high electric field.

This high electric field forms dendritic discharge pores within the polyethylene.

When these dendritic discharge holes are generated, they may grow and penetrate the insulating layer, causing complete circuit breakdown.

Furthermore, it is necessary to use polyethylene with a high molecular weight to reduce water absorption, but when the molecular weight is high, it is difficult to form a thin film during extrusion processing, and a uniform film thickness cannot be obtained.

Therefore, the film thickness of the insulating layer 3 is 0.55 mm to 0.5 mm.
The thickness of the film was approximately 6 mm, and the total film thickness was 0.6 mm to 9.55 mm.

Therefore, an electric motor using this electric wire is a submersible electric motor that has large external dimensions and a heavy weight relative to its output.

The present invention was developed in consideration of these circumstances, and its purpose is to minimize the decrease in dielectric strength due to the occurrence of dendritic discharge holes, and to reduce the drop in dielectric strength due to the formation of dendritic discharge holes.
The object of the present invention is to provide a lightweight water-sealed submersible electric motor.

In order to achieve the above object, the present invention coats a bare copper wire or a copper wire coated with a synthetic resin with a special polypropylene,
The water-sealed submersible electric motor is further characterized in that an electric wire coated with nylon, polyvinylidene fluoride, or ethylenetetraoloethylene copolymer is used on the upper part of the electric wire.

An embodiment of the present invention will be described below with reference to FIG.

In this example, the special polypropylene 4 formed on the shielding layer 2 coated on the copper wire 1 is a blend of ethylene propylene rubber in the form of a polypropylene resin toheret without pre-mixing, and a compounding example is shown in Table 1. Table 1 shows that sample NOI is superior to NO2 in terms of tensile strength, elongation, and volume resistivity.

On the other hand, the mechanical strength is also higher than that of polyethylene resin, but in order to further improve the mechanical strength, the present invention uses nylon, poly7/vinylidene zolide, or a new fluororesin, ethylene tetrafluoro, on the special polypropylene 4 film. It has a protective film made of ethylene copolymer.

It has been confirmed that when electric wires made in this way are immersed in water and a voltage is applied, dendritic discharge holes are much less likely to occur than with conventional electric wires coated with polyethylene resin.

It also has excellent heat resistance and the amount of heat deformation at 120℃ is 0%.
It has also been confirmed that

Among the materials used for the protective film, nylon has a tensile strength of 3
．． It is as high as 9 to 4.7 kgf/mm2 and has a melting point of approximately 21
Can be used at temperatures as high as 0°C.

Furthermore, polyvinylidene fluoride can be used in a temperature range of -60°C to 150°C, and has excellent impact resistance at low temperatures.

Since the melting point is 170°C, it is easy to mold and can be processed at relatively low temperatures.

Next, ethylenetetrafluoroethylene copolymer, a new fluororesin, has a high heat resistance of 180℃ and has high mechanical strength when formed into a film. They have characteristics such as being able to make the film thinner, and these can be used depending on the need.

In the present invention, as shown in Fig. 2, a synthetic resin such as polyester or Holmark is coated as a shielding layer 2 on the outer periphery of an electrical annealed copper wire 1 to a thickness of Q, Q5 mm, and 5 mm, using the various resins described above. Special polypropylene 4 is coated as a film with a thickness of about 0.25 mm to 0.27 mm by extrusion molding, and further, on the outer periphery of this special polypropylene 4, for example, nylon 5 is coated with a thickness of 0.07 mm as an external film.
〜0.08mm coating, total 0.37
The thickness is approximately 0.4 mm.

Table 2 shows the specifications of the electric wire according to the above embodiment.

Figure 3 shows the relationship between the applied voltage and the life time in the above example.
It can be seen that it has a lifespan of over 10,000 hours.

As explained above, the water-sealed submersible electric motor according to the present invention has the following features:
By coating the copper wire with a special polypropylene resin, it prevents the formation of dendritic discharge holes and has high electrical insulation, as well as excellent water resistance, heat resistance, and mechanical strength. Furthermore, the coating is easy to process, and the coating thickness can be reduced. Since a thinner material is used, it is possible to reduce the size and weight, and at the same time, it is possible to obtain a highly reliable product.

In this embodiment, a synthetic resin is baked onto the copper wire 1 as the shielding layer 2, but a bare copper wire without baking the synthetic resin may be used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional electric wire, FIG. 2 is a sectional view of an electric wire according to an embodiment of the present invention, and FIG. 3 is a characteristic diagram of an electric wire according to an embodiment of the present invention. In the figure, 1 is an electrical annealed copper wire, 2 is a shielding layer made of synthetic resin, 4 is an inner coating made of special polypropylene, and 5 is an outer coating made of nylon or the like. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] As the motor winding, the inner coating is a blend of polypropylene and ethylene propylene on bare copper wire or synthetic resin coated copper wire, and on top of this, the outer coating is nylon, polyvinylfluoride, or ethylenetetrofluoroethylene copolymer. A water-sealed submersible electric motor characterized by using a water-sealed submersible motor.