JPH0438143A - Insulation at joint of lead wire and coil lead of motor for refrigerant coller - Google Patents

Abstract

PURPOSE:To obtain an insulation layer excellent in refrigerant resistance by subjecting the joint of a lead wire and the coil lead of a motor to insulation treatment with epoxy resin containing aliphaticamine hardener. CONSTITUTION:Joint of a lead wire 4 and the coil lead 3 of a motor is subjected to insulation treatment with a normal temperature curing epoxy resin containing aliphaticamine as hardener thus forming a compound 6. In other words, a resin composition is varnished on a helical coil 10 and subjected to normal temperature curing thus producing a sample. Resistance against R-123 is then determined for the sample. It was found that extraction to R-123 is low and bent holding rate is high, and no dissolution, swelling nor softening was recognized. Consequently, even if it is employed in a motor for cooling refrigerant R-123, the insulation layer is not corroded by the refrigerant and the circulation piping of refrigerator is prevented from clogging.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to air conditioning equipment such as turbo refrigerators and heat pumps;
The present invention relates to a method of insulating a connection between a coil lead and an output wire of a motor used in refrigerant cooling equipment such as refrigeration equipment.

[Prior art and its problems] Conventionally, trichloromonofluoromethane (hereinafter referred to as R-11
The connection between the coil lead and the lead wire of a motor used in such equipment that circulates refrigerant is insulated as follows.

Figure 2 schematically shows the connection relationship between the coil and lead wire of a motor used in this type of equipment.
As is well known, the coil N is made up of a plurality of coil groups for each use, and one lead terminal of one coil of these groups is electrically connected at the inter-electrode connection (2). For example, assume that the lead wire (4) is connected to the W-phase coil lead (3), which is one of the three phases of the other coils in these groups, at the connection portion (5).

Figure 3 shows the details of this connection part (5).
The conductor connection part (3a) of the coil lead (3) has a flat plate shape, and the lead wire (4) consists of a number of meridians (4b), but the coil lead is insulated at the same time as the coil after mica taping. It is vacuum-pressure impregnated with a heat-curable solvent-free varnish for refrigerants and then pressure-cured, and the lead wire (4) is coated with an insulating film such as Teflon. Its conductor connections (4c) are soldered to a number of meridians (4b). The conductor connection portion (3a) of the coil lead (3) and the conductor connection portion (4c) of the Hiji wire (4) are overlapped and soldered as shown in the figure. In this state, the conductor connections (3a) f4c), the ends of the coil leads (3), and the ends of the output wires (4) are covered with room temperature curing epoxy compound (6) (clay-like or putty-like). The upper mica tape (7) filled with these materials was coated with a liquid room temperature curing epoxy resin, then wound and cured at room temperature for insulation treatment. Note that the room temperature curing epoxy compound and the room temperature curing epoxy varnish use a bisphenol A type or bisphenol F type liquid epoxy resin and an aromatic polyamine curing agent. Electric motors that have been insulated in this way are cooled with the same refrigerant that circulates in the compressor, condenser, pressure reducing device, and evaporator equipment, and some of the refrigerant condensed in the condenser The pump cools the motor coil and lead wire, and the refrigerant itself is heated, evaporated, and returned to the condenser.

However, R-11, which is used as a refrigerant, has the problem of destroying the ozone layer in the stratosphere, and this is being regulated worldwide. Dichlorotrifluoroethane (hereinafter referred to as R-123) is being researched as a candidate for an alternative refrigerant, but this refrigerant has strong swelling and dissolving effects on organic insulating materials used for motor insulation. There is. Therefore, the insulation at the connection between the coil lead and the lead wire of the motor, which is insulated with a room-temperature curing epoxy resin using an aromatic amine curing agent in the refrigerant, is subject to swelling and dissolving effects by this refrigerant. (In addition, melted resin adheres to the discharge valves and circulation system pipes of the refrigerator, causing problems in the operation of the equipment. For this reason, refrigerant R-123 is used for refrigerant cooling. Air conditioning equipment and refrigeration equipment such as centrifugal chillers and heat pumps driven by electric motors could not be easily replaced.

[Problem to be solved by the invention I The change in refrigerant from R-11 to R-123 is a worldwide trend, and the present invention was made in view of this situation.
It is an object of the present invention to provide a method of insulating a connection portion between a coil lead and an outlet wire for a refrigerant cooling device of an electric motor that can withstand the strong swelling and dissolving effects described in No. 3.

Means for Solving Problem c] The above object is to provide a method for insulating the connection between the coil lead and the lead wire of a motor for refrigerant cooling equipment, using dichlorotrifluoroethane as the refrigerant. A connection part between a coil lead and an outlet wire of a motor for refrigerant cooling equipment, characterized in that the connection part between the coil lead and the outlet wire is insulated with a room temperature curing epoxy resin using an aliphatic amine compound as a hardening agent. This is achieved by insulation methods.

[Function] In insulating the connection between the coil lead of the electric motor and the Hiji wire of the present invention, the insulating layer is formed of a room temperature curing epoxy resin cured with an aliphatic amine curing agent. Therefore, the insulating layer has excellent refrigerant resistance of R-123. Therefore, even if this connection insulation is used in R-123, which has a strong swelling and dissolving effect on organic insulating materials, the insulating layer will not dissolve or soften, and the insulation properties will not deteriorate. Very few.

[Example 1] According to the present invention, the connection between the coil lead and the lead wire of the electric motor is insulated with a room temperature curing epoxy resin using an aliphatic amine compound as a curing agent. The following experiments were conducted to confirm the effectiveness.

A sample was prepared by applying a varnish treatment to a helical coil (IO) shown in FIG. 1 using a resin composition having the formulation shown in Table 1, and curing at room temperature. The R-123 resistance of each of these samples was investigated. The helical coil (lO) is made of aluminum lath wire with a diameter of 1111I11, and its length is 70III
la, and the inner diameter was 10 nuw.

Comparison of R-123 resistance was carried out by enclosing the varnished helical coil and R-123 in an autoclave, and
Heated at 5°C for 2 weeks. The weight and bending strength before and after heating were measured, and the amount of R123 extracted was calculated from the change in weight, and the retention rate was calculated from the change in bending strength. The results are shown in Table 2.

(The ratio is the weight ratio) (The bending retention rate is the ratio to the bending strength before the test) From the results in Table 2, it can be seen that the aliphatic polyamine used for insulating the motor coil lid and lead wire connection part of the present invention is used as a hardening agent. The room-temperature-curing epoxy resin has a small amount of R-123 extracted and a high bending retention rate (no dissolution, swelling, or softening was observed, and it has excellent R-123 resistance. In contrast, room-temperature curing epoxy resins that use aromatic polyamine as a curing agent, which have been conventionally used for connection insulation treatment, have a large amount of R-123 extracted and also swell and soften. Therefore, the bending strength retention rate was extremely low, and the R-123 properties were poor.

Next, using the room temperature curable epoxy resin according to the present invention shown in Table 1 and the conventional room temperature curable epoxy resin, a third
Create an insulation sample of the connection part as shown in the figure, and
123 genders were compared.

Connect the lead of the motor coil that has been insulated for R-123 resistance in advance to the Teflon lead wire, and connect this conductor connection part f3a.
) Wrap the part (4c) with an epoxy compound made by mixing silica into the room-temperature-curing epoxy resin shown in Table 1, and wrap mica tape thereon while applying the room-temperature-curing epoxy resin shown in Table 1. A connection insulation model was produced by leaving it at room temperature for 72 hours to harden.

This connection part insulation model was set in an autoclave containing R-123 and heated at 105° C. for two weeks.

Insulation resistance and polarization index were examined before and after this test. The results are shown in Table 3. From these results, it was found that the insulation properties of the connection parts treated with a room-temperature curing epoxy resin using aromatic polyamine as a curing agent decreased after the test compared to before the test, and the insulation layer deteriorated due to R-123. Although it is clear that the connection part insulation of the present invention has almost no deterioration in insulation properties, it has been confirmed that there is no problem in practical use.

As the epoxy resin constituting the connection insulating layer of the present invention, bisphenol A type or bisphenol F type epoxy resin is preferably used. Examples of such epoxy resins include Epicoat 828.827.807 (manufactured by Trading Company 8 Niyoka Shell Co., Ltd.), JIA IIGY-250, and CY-205 (trade name: manufactured by Ciba Geigy Co., Ltd.).

The room temperature curing epoxy resin constituting the connection insulating layer of the present invention is cured using an aliphatic amine curing agent, and aliphatic polyamine is particularly preferably used.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, a centrifugal refrigerator and a heat pump are used as refrigerant cooling equipment, but the present invention is of course not limited to these (it can be applied to general refrigerant cooling equipment).

In addition, in the above embodiment, to insulate both the 4-wire terminal parts of the coil lead and the output wire, they are first wrapped in a room temperature curing epoxy resin compound, and then a liquid room temperature curing resin is applied to the mica tape. After winding the coil lead and leaving it to harden at room temperature, in some cases, the conductive terminal part of the coil lead and the conductive terminal part of the lead wire are coated with high-viscosity room-temperature curing epoxy. coated with resin,
The present invention can also be applied to a material in which insulation treatment is performed by simply curing the material.

Also, the conductive terminal of the coil lead and the conductive terminal of the lead wire are overlapped and wrapped in a room-temperature curing epoxy resin compound, and the mica tape is wrapped while being coated with liquid room-temperature curing epoxy resin. Although the mica tape was cured at room temperature and insulated, a tape made of another insulating material may be wound instead of the mica tape.

[Effects of the Invention] The connection portion between the coil lead and the lead wire of the electric motor of the present invention is as follows:
Because it is insulated with an epoxy resin that uses an aliphatic amine curing agent, it has a strong swelling and dissolving effect.
It also has excellent refrigerant resistance against -123. Therefore, even if the connection insulation of the present invention is used for refrigerant-cooled electric motors used in centrifugal refrigerators, heat pumps, and other air conditioning equipment that use R-123 as the refrigerant, and refrigeration equipment, the refrigerant R-123
123, which causes the insulation layer to melt and deteriorate the insulation, and prevents accidents such as clogging of the circulatory system tubes of the refrigerator.

Also, R-1 can be used as a refrigerant in turbo refrigerators, heat pumps, etc.
23 can be used, so even if the refrigerant leaks, it will not destroy the stratospheric ozone layer.

[Brief explanation of drawings]

FIG. 1 is a side view of a sample used to confirm the durability against refrigerant of a room temperature curing epoxy resin used for insulating the connection between the coil lead and the lead wire of the refrigerant cooling motor according to the present invention; FIG. 2 is a schematic side view showing the connection between the coil lead and the lead wire of the motor, and FIG. 3 is an enlarged sectional view showing details of the connection in FIG. 2, in order to show the part to which the present invention is applied. It is. In the figure, (3) ・ ・ ・ ・ ・ ・ ・ ・ Coil lead (4) ・・・・・
・・・ Exit line (6) ・・・
・・・・・・・・・Room temperature curing epoxy resin compound (7)・・・・・・・Mica tape No. 1rIJ Agent Han Yasuo Figure 2 Figure 3 Figure 6…… Room temperature curing epoxy resin compound 7
°゛゛゛°Mica table (voluntary) procedural amendment placement

Claims (3)

[Claims] (1) In a method of insulating the connection between the coil lead and the output wire of a motor for refrigerant cooling equipment, dichlorotrifluoroethane is used as the refrigerant, and the connection between the motor coil lead and the output wire is insulated using an aliphatic amine. A method for insulating a connection between a coil lead and an output wire of a motor for refrigerant cooling equipment, characterized in that the connection part is insulated with a room-temperature curing epoxy resin using a type compound as a hardening agent. (2) The insulation method according to claim (1), wherein the aliphatic amine compound is an aliphatic polyamine. (3) The room temperature curing epoxy resin is bisphenol A
Claim (1) which is a type resin or bisphenol F type resin
Or the insulation method described in (2).