JPS6010433B2 - Manufacturing method of insulated conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an insulated conductor, and more particularly to a method for applying insulation on a conductive atomized body having a connection portion of dissimilar metals by an electrical bonding method.

Conventionally, a method known to those skilled in the art is a method of attaching a water-soluble varnish to form an insulating film as an insulating method for dissimilar metal trailing parts.

This water-repellent varnish has the advantage that it has good throwing power and that the electrical shielding effect of the deposited coating film prevents polarization between different metals from having an adverse effect on the coating film, resulting in a good insulating film. However, on the other hand, it is not suitable for insulation using relatively high voltages because a thick film cannot be obtained due to the above-mentioned electrical shielding effect. On the other hand, water-dispersed varnish has poor throwing power and cannot serve as a complete electrical shielding film, and therefore, the polarization effect caused by the difference in ionization tendency of each metal at the joint between dissimilar metals partially promotes haze deposition. Therefore, it is not possible to obtain a uniform insulating film. However, single metals generally have the characteristic that a thick film can be obtained, which is convenient for insulation. The present inventors have previously proposed a dew coating method using water-dispersed varnish mixed with mica scales as a method of insulating the coils of rotating machines, which have harsh thermal, electrical, and mechanical operating conditions. (For example, Tokusekki No. 51-89178, Japanese Unexamined Patent Publication No. 51-1
14602, JP-A No. 51-114603, etc.) These are related to haze deposition on a conductor made of a single metal material, and are applied to connections between dissimilar metals, contact sections between dissimilar metals, or joints. (These are collectively referred to as "connections") are coated with the same effect as the water-dispersed varnish mentioned above.In other words, in the joints of dissimilar metals, uneven film thickness occurs. This made it unsuitable for practical use.

Specific examples of joints between dissimilar metal materials include parts where electrical conductors made of steel are brazed with brazing material and electrically connected, such as the series joints of stator coils in rotating electric machines, or parts where dissimilar metals are electrically connected. spot welding of materials,
Examples include connection parts made by welding etc., parts joined by press-fitting, parts connected by screws, screws, etc.

Conventionally, the subsequent insulation of the dissimilar metal material as described above was carried out by an operator manually winding a thin insulating material such as mica tape.

This invention was made in view of the above circumstances, and is an insulated conductor that can easily provide an insulating coating with a uniform thickness that can withstand high voltage and high temperature on a conductor having a connection part of different metal materials. The present invention aims to provide a method for manufacturing.

As a result of various studies conducted by the present inventors based on the above-mentioned problems,
Rumor has it that by raising the specific resistance of the paint solution above a predetermined value and electrodepositing it, we have found a new fact that the objective can be achieved, and have completed this invention.

That is, the present invention provides an electrical conductor having a connection portion between a first electrical conductor and a second electrical conductor made of a different material from the first electrical conductor, using mica scales and water having a resistivity of 300,001 or more. This is a method for producing an insulated conductor, which comprises soaking a frosting paint in which a dispersed varnish is dispersed, and providing a co-electrodeposition film on the connection portion.

That is, if the polarization voltage generated between different metals is △V, and the electroplating voltage is V (value converted to electric field strength), then △V'
When V is smaller than 1'10, the influence of non-uniformity in film thickness due to polarization voltage is almost eliminated.

Here, △V'V should be reduced simply by increasing the dew voltage, but if electrodeposition is carried out at too high a voltage, electrolysis of the deposited paint may occur, and the convection of the liquid caused by this, as well as the pH increase. Changes may have a negative effect on the paint film. However, in the case of an electrocoating liquid containing mica scales, unless a relatively high voltage is applied, the mica scales will be difficult to deposit on the coating, so the inventors set the liquid resistance of the electrocoating paint to 30,000. By holding the dew paint, which can be rubbed off at a relatively high voltage,
I ended up putting it out. As a method for increasing this liquid resistance, commonly used dialysis or electrodialysis may be used as appropriate. The liquid resistance value is determined by the amount of water-dispersed varnish that is a component of the haze paint. As mentioned above, the present inventors have proposed, for example, that the amount of varnish used in high-voltage rotating machine insulation should be reduced, and that electrodeposition coating liquids (water-dispersed varnish should be about 3% by weight based on the total solids content) should be used. less)
So even 30,000 skin is enough to reach the goal. Generally, considering the stability of the coating liquid, 4000Q/skin or higher is suitable. There are no particular restrictions on the type of water-dispersed varnish, the type of other insulating materials, or their amounts.Using a lightning coating liquid adjusted in this way, it can be applied evenly to joints made of dissimilar metals. Next, the present invention will be explained in more detail with reference to comparative examples and examples.

Comparative example 1 Bisphenol type epoxy resin (Epicote 1001,
(manufactured by Shell Chemical Co., Ltd.) 8 anchor parts, 1 tetrahydrophthalic anhydride
In a water-dispersed varnish consisting of 8 parts of ethylene glycol and 2 parts of ethylene glycol, add 35-mesh mica powder thoroughly washed with ion-exchanged water to 1 part of the resin content of the water-dispersed varnish.
Add water and mix thoroughly to reduce the total non-volatile content to 1.
A 5% haze paint solution was prepared.

The liquid resistance of this mist paint was 76001 arc. The series connection part of the stator coil of an induction motor was immersed in this mist coating, and a DC voltage of 50 V was applied between the opposing electrodes for 3 brightnesses. After drying, an uneven insulating layer was obtained.
Furthermore, this induction motor was completely impregnated, and after heating, the withstand voltage of the series connection part was measured, and it was 1 V. Comparative Example 2 A wound rotor series insulating part (with solder) was immersed in an electrodeposition paint solution obtained in exactly the same manner as in Comparative Example 1, and a DC voltage of 80 V was applied for 20 seconds between the opposing electrodes, and then dried. As a result, a tortoise layer with quite large undulations was obtained.

Furthermore, when the induction motor was completely impregnated and the withstand voltage of the exposed portion after heating was measured, it was 21 kV. Comparative Example 3 Bisphenol type epoxy resin (Epicote 1001,
(manufactured by Shell Chemical Co., Ltd.) 8 parts, 1 part of tetrahydrophthalic anhydride
Mix 80 mesh mica powder in a water-enhanced varnish consisting of 8 parts of ethylene glycol and 2 parts of ethylene glycol at a ratio of 9 parts to 1 part of the resin content of the water-dispersed varnish, add water and mix well. Based on this, a liquid coating solution with a total non-volatile content of 15% was prepared.

The liquid resistance of this exposed coating liquid was 3800 arc. Next, the phase ring of the transfer motor is immersed in this box paint liquid,
A DC voltage of 60 V was applied for 60 seconds between the counter electrode and the layer was dried to obtain an exposed layer with irregularities. Furthermore, this induction motor was fully impregnated and the withstand voltage after heating was measured.
It was 3kV. Comparative Example 4 The place ring part of the induction motor was immersed in the same electrodeposition liquid paint as in Comparative Example 3, and a DC voltage of 50 V was applied between it and the counter electrode for 45 seconds to dry it, resulting in a considerably uneven exposed layer. I got it.

Furthermore, this induction electric motor. When the machine was completely impregnated and the withstand voltage of the exposed part after heating was measured, it was 17 kV. Comparative example
5 The field pole part of the induction motor was immersed in the same dew liquid paint as in Comparative Example 3, and a DC voltage of 80 V was applied between it and the counter electrode at 39°C.
When the powder was applied in stages and during drying, an uneven coating layer was obtained.

Furthermore, this induction motor was completely impregnated, and the withstand voltage of the exposed portion after heating was measured and found to be 19 kV. Example 1 Bisphenol type eboxy resin (Epicote 1001,
(manufactured by Shell Chemical Co.) 8 anchors, 1 tetrahydrophthalic anhydride
In a water-dispersed varnish consisting of 8 parts and 2 parts of ethylene glycol, add 35 mesh mica powder thoroughly washed with ion-exchanged water to 1 part of the resin content of the above-mentioned water-dispersed varnish.
An electrodeposition coating solution with a total non-volatile content of 15% was prepared by adding ion-exchanged water to the electrodeposition coating solution.

Next, this exposed paint liquid was applied to a dialysis machine to remove miscellaneous ions and reduce the liquid resistance to 50,000.
A DC voltage of 50 V was applied between the opposing electrodes for 30 seconds to obtain a uniform insulating layer with a thickness of 1.1 after drying.

Furthermore, when this induction motor was completely impregnated and heated, the withstand voltage of the series joint was measured and found to be 40 kV or more.
Example 2 An electrodeposition paint solution was prepared in the same manner as in Example 1, and the solution was further passed through a dialysis machine to remove impurities and reduce the resistance to 8000.
After reducing the temperature to zero, the insulating part of the wound rotor series (with solder) of the induction motor was immersed, and a DC voltage of 80 V was applied between the opposing electrodes to a thickness of 1.2 mm after drying. A uniform insulation layer was obtained.

Furthermore, when this induction motor was completely impregnated and heated, the withstand voltage of the exposed portion was measured, and it was found to be 40 kV or more. Example
3 In the same manner as in Example 1, 3 to 2 resin content of the water dispersion was added.
Prepare a lightning coating solution mixed with 8 parts of 5-mesh mica powder, apply this solution to a dialysis machine to remove impurities, and reduce the resistance to 100,000. The ring was immersed and a DC voltage of 60 Y was applied between it and the counter electrode for 4 hours to obtain a uniform insulating layer with a thickness of 1.3 ribs after drying.

Furthermore, this induction motor was completely impregnated and the withstand voltage of the casing portion after heating was measured and found to be 40 kV or more. Example 4 A tortoise paint solution was prepared in the same manner as in Example 1, and this solution was further passed through a dialysis machine to remove impurities and reduce the liquid resistance to 120,000.
・After cleaning, soak the place ring part of the induction motor,
Applying a DC voltage of 5 volts for 30 seconds between the opposing electrodes,
After drying, a uniform insulating layer with a thickness of 1.1 was obtained.

Furthermore, when this induction motor was completely impregnated and the withstand voltage of the same electrodeposited part after heating was measured, it was 40 kV or more. Example 5 An electrodeposition coating solution was prepared in the same manner as in Example 1, and the solution was further passed through a dialysis machine to remove impurities and reduce the resistance to 210,000.
・After drying, the field coil pole of the induction motor is submerged, and a DC voltage of 80 V is applied between two capes of sand between the opposing electrodes to form a uniform insulating layer with a thickness of 1.2 ribs after drying. Obtained.

Further, this induction motor was completely impregnated, and after heating, the withstand voltage of the hazed portion was measured, and it was found to be 40 kV or more. Next, various characteristics obtained in the above comparative examples and examples are summarized in Table 1,
The effects of the present invention are shown.

Table 1 xl was set as "approximately" because the thickness could not be accurately measured due to unevenness and the average value was taken.

Claims (1)

[Scope of Claims] 1. A conductor having a connection portion between a first electric conductor and a second electric conductor made of a different material from the first electric conductor.
A method for producing an insulated conductor, which comprises immersing the insulated conductor in an electrodeposition paint in which mica scales and water-dispersed varnish having a specific resistance of 000 Ω·cm or more are dispersed, and providing a co-electrodeposition film on the connection portion. 2. The method of manufacturing an insulated conductor according to claim 1, wherein a stator coil having a series connection part of a rotating electric machine is used as the conductor.