JP2006262559A - Coil of rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil of a rotating electric machine that has a stable corona prevention function and is enhanced in power application lifetime characteristics and resistance to heat. <P>SOLUTION: The coil comprises: a coil conductor 7 constituted by bundling a plurality of insulated electric wires applied with insulating coatings; a mica-insulating layer 5 formed at the external periphery of the coil conductor 7; and a low-resistance corona prevention layer 6 formed at the external periphery of the mica insulating layer 5. The low-resistance corona prevention layer 6 has a conductive tape or a sheet, and an impregnated resin that is impregnated in the conductive tape or the sheet and hardened. The conductive tape or the sheet is formed by applying or impregnating conductive paint, having at least an unsaturated polyester resin as one component to a backing material constituted of inorganic fibers. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coil of a rotating electric machine that includes a low-resistance corona prevention layer and is used as an armature coil of a synchronous machine or a DC machine, a stator coil of an induction motor, or the like.

  In a high-voltage rotating electrical machine with a rated voltage of 3000 V or higher, the corona is placed on the outermost layer of the armature coil in order to suppress discharge deterioration due to the gap generated between the coil insulation outer surface and the iron core, or to equalize the electric field in the coil insulation. A conductive layer called a prevention layer is provided. This reduces the deterioration of the insulation characteristics due to the deterioration of the discharge acting by the power of the electric field, so that the coil insulation thickness can be reduced, and the device can be reduced in size and weight, and the output density can be increased (see Patent Document 1). .

  On the other hand, a vehicular main motor having a rated voltage of 1500 V or less often does not employ a corona prevention layer because the voltage is low and the influence of discharge deterioration is less. However, while many high-voltage rotating electrical machines have an operating temperature of 155 ° C. or lower, a vehicular main motor may be operated at 220 ° C., and an insulation system with higher heat resistance is employed.

In recent years, there is an increasing demand for main motors for vehicles driven at 3000V in some regions overseas. Since the voltage increases, there is a concern about the effect of discharge deterioration. For example, a corona-preventing layer excellent in heat resistance that can be operated at 220 ° C. or higher, and a rotating electrical machine using the same are desired.
Japanese Patent Laid-Open No. 2-106812

  Several methods are conceivable for obtaining a corona-preventing layer having excellent heat resistance that can be operated at a target operating temperature or higher, for example, 220 ° C. or higher as described above. One is a method of forming a conductive tape and a sheet using only a material having a heat resistance equal to or higher than a target operating temperature, and the other is a method for ensuring heat resistance as a system in combination with an impregnating resin. For the latter of these, by using an impregnating resin having a heat resistance higher than the current level, a method for supplementing the corona-preventing tape with low heat resistance, and combining the current impregnating resin with the current corona-preventing tape with low heat resistance The system can be divided into methods for ensuring heat resistance.

  In general, coil insulation of rotating electrical machines requires long-term evaluation, and newly developed materials may cause problems during use due to unexpected causes. Therefore, instead of developing a new insulating material, we use impregnated resin and low-resistance corona-preventing materials that have been proven so far. A corona-preventing layer and a rotating electric machine coil using the same are desired.

  In view of such circumstances, it is an object of the present invention to provide a coil for a rotating electrical machine having a stable corona prevention function and having excellent electric charging life characteristics and heat resistance.

  In order to solve the above-mentioned problems, the invention of claim 1 is directed to a coil conductor formed by converging a plurality of insulated wires provided with an insulation coating, a mica insulating layer formed on an outer periphery of the coil conductor, and the mica A low-resistance corona prevention layer formed on the outer periphery of the insulating layer, and the low-resistance corona prevention layer comprises a conductive tape or sheet and an impregnated resin impregnated and cured in the conductive tape or sheet. The conductive tape or sheet is formed by applying or impregnating a base material made of inorganic fibers with a conductive paint having at least an unsaturated polyester resin as a component, and a polyimide-modified epoxy resin is used as the impregnation resin. The configuration.

  ADVANTAGE OF THE INVENTION According to this invention, it can provide the coil of the rotary electric machine which has the stable corona prevention function and was excellent in the electrical charging lifetime characteristic and heat resistance.

  As shown in FIG. 1, the coil of the rotating electrical machine according to the present embodiment is composed of at least one of peeled mica or laminated mica on a coil conductor 7 formed by converging a plurality of insulated wires with insulating coatings. A mica layer, a mica layer reinforcing material composed of at least one of organic fiber, organic film, or inorganic fiber, and a thermosetting or thermoplastic polymer resin that integrates them together, A mica insulating layer 5 is formed by winding at least a mica tape or a mica sheet as a constituent material, and a low resistance corona prevention layer 6 is formed by winding a conductive tape or sheet as the outermost layer. The conductive tape or sheet for forming the low-resistance corona prevention layer 6 is formed by applying or impregnating a conductive paint having at least an unsaturated polyester resin as a component to a substrate made of inorganic fibers, and the mica insulating layer 5 A polyimide-modified epoxy resin is used as the impregnation resin for the low-resistance corona prevention layer 6.

  With such a configuration, for example, a coil for a rotating electrical machine is provided in which the constituent material of the low-resistance corona prevention layer 6 is less thermally decomposed / deteriorated and loses its function even after thermal deterioration corresponding to 20,000 hours at 220 ° C. be able to.

  In the present embodiment, the surface resistivity of the low-resistance corona prevention layer 6 is set to 50Ω to 10,000Ω so that the iron core and the coil surface can be kept at the same potential even after thermal deterioration to have a corona prevention function. In addition, eddy current loss generated in the low-resistance corona prevention layer 6 on the coil surface by magnetic flux generated in the rotating electric machine during operation can be suppressed.

  Hereinafter, the coil of the rotating electrical machine of the present embodiment will be described by comparing an example with a comparative example.

(Example)
This will be described with reference to FIGS.
As shown in FIG. 2, hard unfired laminated mica tape 1 (t (thickness) 1.0 mm × w (width) 17 mm), which is one of the constituent materials of the coil of the rotating electrical machine according to the present embodiment, is It is manufactured by impregnating and curing silicone resin as mica tape adhesive 4 to hard unfired laminated mica paper 2 and polyimide film 3 (nominal thickness 25μm, type H, manufactured by Toray DuPont) made from bite. The

  The total length of the coil conductor 7 (12 × 16 × 400 mm) formed by bundling the insulation-coated rectangular electric wire wound with the polyimide film as shown in FIG. Then, the mica tape 1 is wound 4 times so that it overlaps by 1/2 the width of the tape, and a polyimide tape with a width of 17mm (nominal thickness 25μm, typeH made by Toray DuPont) is also halved on it. 4 times to form a polyimide tape insulating layer 8.

  Next, a conductive tape 17 (t0.1 × w25) formed by applying a conductive paint composed of unsaturated polyester resin 15 and carbon particles 16 to glass cloth 14 as shown in FIG. After being wound once in a stack of 1/2 within a range of 230 mm, the iron core 10 is housed in the iron core 10 so as to be in the winding range of the conductive tape 17, and fixed with a wedge 11, and then the imide-modified epoxy resin composition 12 ( TVB2711, manufactured by Kyocera Chemical Co., Ltd.) was vacuum impregnated. The wound portion of the conductive tape 17 forms the low resistance corona prevention layer 6. The vacuuming condition is 10.0 Pa for 1 hour, and the pressurization is 0.5 MPa for 0.5 hour.

  Then, the coil of the rotary electric machine which has heat-hardened in the hot-air circulation type thermostat, and has the low resistance corona prevention layer 6 was obtained. Heat curing was carried out in a hot air circulation thermostat at 180 ° C. for 20 hours.

(Comparative example)
As shown in FIG. 4, instead of the conductive tape 17 in the above embodiment, a glass cloth (t0.1 × w0.25) is wound once in a 1/2 layer to form a glass cloth insulating layer 9, and an iron core is formed. The coil was placed in 10 slots. Thereafter, the same treatment as in the above example was performed to obtain a coil of a rotating electric machine having no corona prevention layer.

  For both coils of the comparative example and the example thus obtained, the iron core 10 was grounded, and three types of alternating voltages (50 Hz) were applied to the coil conductor 7 at room temperature. Then, the time to ground fault, that is, the electric charging life, was measured and compared. The result is shown in FIG. For each coil of the comparative example and the example, evaluation is performed with 10 coils for each measurement voltage. And the approximated curve which processed the 50% destruction probability value which statistically processed the electric charging life of each coil by Weibull distribution by the least square method is shown. From FIG. 5, the example using the conductive tape 17 produced using the unsaturated polyester resin shows that the electric charging life is increased about three times as compared with the comparative example not using the conductive tape 17. I can confirm.

  Next, thermal deterioration corresponding to 20000 hours at 220 ° C. was applied to the coil of the example in a hot air circulating thermostat. And the time-dependent change of the surface resistivity of the corona prevention layer in the coil surface was measured. The result is shown in FIG. FIG. 6 shows that the coil of the example in which the conductive tape 17 using the unsaturated polyester was wound and the imide-modified epoxy resin composition 12 was used as the impregnating resin even after predetermined thermal deterioration was obtained. It can be confirmed that the surface resistivity of the prevention layer is stable.

  Finally, both the coils of the comparative example and the example were subjected to thermal degradation corresponding to 20000 hours at 220 ° C., and then an electric charging test was performed at a predetermined voltage to measure the electric charging life. The result is shown in FIG. From FIG. 7, it can be confirmed that the example has an effect of extending the life about three times as compared with the comparative example even in the power deterioration after the thermal deterioration.

  As described above, a conductive tape or sheet obtained by applying a conductive paint having at least an unsaturated polyester resin as a component to a substrate made of inorganic fibers and an impregnated resin made of a polyimide-modified epoxy resin are used in combination. As a result, a low-resistance corona-preventing layer with less thermal decomposition and deterioration of the constituent material and less loss of its function can be obtained, extending the life of the coil, and reducing the size and weight of the rotating electrical machine and improving the output density. Can be planned.

Sectional drawing which shows the coil of the rotary electric machine of the Example of this invention. Sectional drawing of the mica tape used for the coil of the rotary electric machine of the Example of this invention. Sectional drawing of the electroconductive tape used for the coil of the rotary electric machine of the Example of this invention. Sectional drawing of the coil of the rotary electric machine of a comparative example. The graph which shows the electrical charging lifetime of the coil of the rotary electric machine of the Example of this invention, and a comparative example. The graph which shows the time-dependent change of the surface resistivity when applying the thermal history corresponding to 20000 hours for 220 degreeC to the coil of the rotary electric machine of the Example of this invention. The table | surface which shows the electrical charging lifetime when the thermal history of 220 degreeC and 20000 hours is added to the coil of the rotary electric machine of the Example of this invention, and a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Hard unfired laminated mica tape, 2 ... Hard unfired laminated mica paper, 2a ... Mica piece, 3 ... Polyimide film, 4 ... Mica tape adhesive, 5 ... Mica insulating layer, 6 ... Low resistance corona prevention layer, 7 DESCRIPTION OF SYMBOLS ... Coil conductor, 8 ... Polyimide tape insulating layer, 9 ... Glass cloth insulating layer, 10 ... Iron core, 11 ... Wedge, 12 ... Imido modified epoxy resin composition, 14 ... Glass cloth, 15 ... Unsaturated polyester resin, 16 ... Carbon Particles, 17 ... conductive tape.

Claims (2)

  A coil conductor formed by converging a plurality of insulated wires provided with an insulation coating, a mica insulating layer formed on the outer periphery of the coil conductor, and a low-resistance corona prevention layer formed on the outer periphery of the mica insulating layer. The low-resistance corona prevention layer comprises a conductive tape or sheet and an impregnated resin impregnated and cured in the conductive tape or sheet, and the conductive tape or sheet is made of an inorganic fiber. A coil for a rotating electrical machine, wherein a conductive coating having at least an unsaturated polyester resin as one component is applied or impregnated, and a polyimide-modified epoxy resin is used as the impregnating resin. 2. The rotating electrical machine coil according to claim 1, wherein the low resistivity corona prevention layer has a surface resistivity of 50 [Omega] to 10,000 [Omega].

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