Binding characteristic evaluation method of epoxy glass powder mica tape for stator coil

Abstract

The invention provides a binding characteristic evaluation method of an epoxy glass powder mica tape for a stator coil, and belongs to the technical field of generator stator coil materials. When the epoxy glass powder mica tape is applied to the preparation process of the generator stator coil, the binding characteristic (influence on the performance of a final product) is related to the mechanical properties in the length and thickness directions, and is also related to the deformation characteristic when the epoxy glass powder mica tape is subjected to a certain stress in the length and thickness directions; corresponding analysis method is designed, relevant parameters are obtained, a formula is designed to calculate evaluation parameters reflecting the binding characteristic of the epoxy glass powder mica tape, and therefore accurate and rapid evaluation on the binding characteristic of the epoxy glass powder mica tape is achieved, and the calculation formula is as follows: # imgabs0 #.

Description

Technical Field

[0001] The invention provides a method for evaluating wrapping characteristics of an epoxy glass powder mica tape facing a stator coil, belonging to the technical field of generator stator coil materials. Background Art

[0002] At present, the stator coils of large generator sets mainly adopt a one-time molding anti-corona structure, that is, the stator bar main insulation (several layers of epoxy glass powder mica tape wrapped around the copper core) is impregnated with bisphenol A epoxy resin (uncured), wrapped with high-resistance anti-corona tape, and then wrapped with an anti-corona protective layer (epoxy glass powder mica tape, consistent with the main insulation material), and then hot-pressed and cured by a mold at high temperature, so that the anti-corona tape and the main insulation, copper core, and anti-corona protective layer are cured into an integrated structure. Among them, epoxy glass powder mica tape is generally a strip-shaped insulating material made of mica paper as the base material, phenolic epoxy tungsten maleic anhydride adhesive paint as the adhesive, and electrical alkali-free glass cloth on both sides as the reinforcement material. It has good softness under normal conditions. After being wrapped around the coil and processed, it has high electrical performance and mechanical strength.

[0003] The deformation characteristics of epoxy glass powder mica tape (here called wrapping characteristics) have a great influence on the shape, long and short side thickness, etc. of the main insulation of the stator wire rod after wrapping the copper core. Inappropriate deformation behavior will lead to different thicknesses of the long and short sides of the main insulation section of the stator wire rod, and will also cause the corners of the product to be too sharp after wrapping; on the other hand, it has an important influence on the impregnation characteristics of the impregnating resin, and the mechanical properties, dielectric properties and other important performance properties of the final stator coil product. Therefore, studying and expressing the wrapping characteristics of epoxy glass powder mica tape is of great significance for the research and development and design of high-performance stator coils. However, there is currently a lack of relevant rapid and accurate characterization methods, and in-depth research and development is urgently needed.

[0004] Therefore, there is an urgent need to provide a method that can quickly and accurately evaluate the wrapping properties of epoxy glass powder mica tape for stator coils. Summary of the invention

[0005] In order to achieve the above-mentioned purpose, the present invention provides a method for evaluating the wrapping characteristics of epoxy glass powder mica tape for stator coils to solve the technical problems thereof.

[0006] The present invention is based on the fact that the wrapping characteristics (the influence on the performance of the final product) of the epoxy glass powder mica tape in the preparation process of the generator stator coil are not only related to its mechanical properties in the length and thickness directions, but also related to its deformation characteristics when subjected to certain stress in the length and thickness directions. By designing a corresponding analysis method, obtaining relevant parameters, and designing a formula to calculate the evaluation parameters reflecting the wrapping characteristics of the epoxy glass powder mica tape, the accurate and rapid evaluation of the wrapping characteristics of the epoxy glass powder mica tape is achieved. The specific evaluation method is as follows:

[0007] (1) The mechanical properties of epoxy glass powder mica tape were tested and its tensile strength S along the length direction was measured. t ;

[0008] (2) Using a universal mechanical testing machine, stretch the epoxy glass powder mica tape along the length direction with a tensile stress F. After stabilization, measure the corresponding strain value D t ;

[0009] (3) The epoxy glass powder mica tape was stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c ; Obtain the slope V of the compressive stress-strain curve slope ;

[0010] (4) The epoxy glass powder mica tape is stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine is used to compress it with a compressive stress P. After stabilization, the corresponding strain value D is measured. c ; Then remove the compressive stress, record the strain recovery after release, and calculate the rebound rate R along the thickness direction;

[0011] (5) According to the following formula, calculate the evaluation parameter P of the wrapping characteristics of epoxy glass powder mica tape TAPE , P TAPE The larger the value, the better the performance when wrapping the generator stator coil, and the better the macroscopic performance of the product after wrapping:

[0012]

[0013] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

[0014] Furthermore, the test method for tensile strength in step (1) is carried out in accordance with GB / T1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles".

[0015] Furthermore, the test method in step (3) is carried out in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics".

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention proposes for the first time a method for quickly evaluating the wrapping characteristics of epoxy glass powder mica tape facing the stator coil, which is reliable, fast and highly accurate.

[0018] (2) The method provided by the present invention can be used to quickly evaluate the wrapping characteristics of the epoxy glass powder mica tape facing the stator coil, and provide guidance for the research, development, design and application of the epoxy glass powder mica tape facing the stator coil. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described in detail below in conjunction with the embodiments. It is necessary to point out that the following embodiments are only used to explain and illustrate the present invention and are not used to limit the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content still belong to the protection scope of the present invention.

[0020] Example 1

[0021] A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing a stator coil comprises the following steps:

[0022] (1) The mechanical properties of epoxy glass powder mica tapes A and B were tested respectively, and their tensile strength S along the length direction was measured. t-A =128N / 10mm, S t-B =110N / 10mm, the test method is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles";

[0023] (2) Using a universal mechanical testing machine, epoxy glass powder mica tapes A and B were stretched along the length direction at a tensile stress of F = 13N / 10mm. After stabilization, the corresponding strain value D was measured. t-A =1.3%, D t-B =2.2%;

[0024] (3) Epoxy glass powder mica tapes A and B were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c-A =99MPa, S c-B =60MPa; obtain the slope V of the compressive stress-strain curve slope-A =1.3, V slope-B=12, the test method is in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics";

[0025] (4) Epoxy glass powder mica tapes A and B are stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine is used to compress them with a compressive stress of P = 50 MPa. After stabilization, the corresponding strain value D is measured. c-A =28%, D c-B =44%;

[0026] (5) According to the following formula, the evaluation parameters for measuring the wrapping characteristics of epoxy glass powder mica tape A and B are calculated as P TAPE-A =61.1, P TAPE-B =20.4. TAPE-A >P TAPE-B , indicating that the better the performance of epoxy glass powder mica tape A in wrapping the generator stator coil, the better the macroscopic performance of the wrapped product. Through the comparative experimental study of actual wrapped products, impregnated resin treatment and solidification molding, it was found that the stator coil cross-section of the products obtained by epoxy glass powder mica tape A has a smaller difference in thickness between the long and short sides, softer edges and corners, better absorption and spreadability of impregnated resin, that is, better wrapping characteristics, proving that the calculation results of this project are highly accurate.

[0027]

[0028] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

[0029] Example 2

[0030] A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing a stator coil comprises the following steps:

[0031] (1) The mechanical properties of epoxy glass powder mica tapes C and D were tested respectively, and their tensile strength S along the length direction was measured. t-C =143N / 10mm, S t-D =129N / 10mm, the test method is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles";

[0032] (2) Using a universal mechanical testing machine, epoxy glass powder mica tapes C and D were stretched along the length direction at a tensile stress of F = 44N / 10mm. After stabilization, the corresponding strain value D was measured. t-C =4.1%, D t-D =5.0%;

[0033] (3) Epoxy glass powder mica tapes C and D were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c-C =118MPa, S c-D =65MPa; obtain the slope V of the compressive stress-strain curve slope-C =34, V slope-D =21, the test method is in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics";

[0034] (4) Epoxy glass powder mica tapes C and D are stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine is used to compress them with a compressive stress of P = 44 MPa. After stabilization, the corresponding strain value D is measured. c-C =22%, D c-D =27%;

[0035] (5) According to the following formula, the evaluation parameters for measuring the wrapping characteristics of epoxy glass powder mica tapes C and D are calculated as P TAPE-C =55.2, P TAPE-D =44.3. TAPE-C >P TAPE-D , indicating that the better the performance of epoxy glass powder mica tape C in wrapping the generator stator coil, the better the macroscopic performance of the wrapped product. Through the comparative experimental study of actual wrapped products, impregnated resin treatment and solidification molding, it was found that the coil cross-section of the products obtained by epoxy glass powder mica tape C has a smaller difference in thickness between the long and short sides, softer edges and corners, better absorption and spreadability of impregnated resin, that is, better wrapping characteristics, proving that the calculation results of this project are highly accurate.

[0036]

[0037] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

[0038] Example 3

[0039] A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing a stator coil comprises the following steps:

[0040] (1) The mechanical properties of epoxy glass powder mica tapes E and F were tested respectively, and their tensile strength S along the length direction was measured. t-E =200N / 10mm, S t-F =139N / 10mm, the test method is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles";

[0041] (2) Using a universal mechanical testing machine, epoxy glass powder mica tapes E and F were stretched along the length direction at a tensile stress of F = 59N / 10mm. After stabilization, the corresponding strain value D was measured. t-E =3.0%, D t-F =3.9%;

[0042] (3) Epoxy glass powder mica tapes E and F were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c-E =84MPa,S c-F =115MPa; obtain the slope V of the compressive stress-strain curve slope-E =3.9, V slope-F =12, the test method is in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics";

[0043] (4) Epoxy glass powder mica tapes E and F were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine was used to compress them with a compressive stress of P = 31 MPa. After stabilization, the corresponding strain value D was measured. c-E =32%, D c-F =21%;

[0044] (5) According to the following formula, the evaluation parameters for measuring the wrapping characteristics of epoxy glass powder mica tapes E and F are calculated as P TAPE-E =126.5, P TAPE-F =77.6. TAPE-E >P TAPE-F , indicating that the better the performance of epoxy glass powder mica tape E in wrapping the generator stator coil, the better the macroscopic performance of the wrapped product. Through the comparative experimental study of actual wrapped products, impregnated resin treatment and solidification molding, it was found that the coil cross-section of the products obtained by epoxy glass powder mica tape E has a smaller difference in thickness between the long and short sides, softer edges and corners, better absorption and spreadability of impregnated resin, that is, better wrapping characteristics, proving that the calculation results of this project are highly accurate.

[0045]

[0046] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

[0047] Example 4

[0048] A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing a stator coil comprises the following steps:

[0049] (1) The mechanical properties of epoxy glass powder mica tapes H and I were tested respectively, and their tensile strength S along the length direction was measured. t-H =144N / 10mm, S t-I =157N / 10mm, the test method is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles";

[0050] (2) Using a universal mechanical testing machine, the epoxy glass powder mica tapes H and I were stretched along the length direction at a tensile stress of F = 88N / 10mm. After stabilization, the corresponding strain value D was measured. t-H =5.7%, D t-I =4.8%;

[0051] (3) Epoxy glass powder mica tapes H and I were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c-H =120MPa, S c-I =68MPa; obtain the slope of the compressive stress-strain curve V slope-H =44, V slope-I =19, the test method is in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics";

[0052] (4) Epoxy glass powder mica tapes H and I were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine was used to compress them with a compressive stress of P = 20 MPa. After stabilization, the corresponding strain value D was measured. c-H =31%, D c-I =26%;

[0053] (5) According to the following formula, the evaluation parameters for measuring the wrapping characteristics of epoxy glass powder mica tape H and I are calculated as P TAPE-H =47.1, P TAPE-I =57.8. TAPE-I >P TAPE-H , indicating that the better the performance of epoxy glass powder mica tape I in wrapping the generator stator coil, the better the macroscopic performance of the wrapped product. Through the comparative experimental study of actual wrapped products, impregnated resin treatment and solidification molding, it was found that the coil cross-section of the products obtained by epoxy glass powder mica tape I had a smaller difference in thickness between the long and short sides, softer edges and corners, better absorption and spreadability of impregnated resin, that is, better wrapping characteristics, proving that the calculation results of this project are highly accurate.

[0054]

[0055] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

[0056] Example 5

[0057] A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing a stator coil comprises the following steps:

[0058] (1) The mechanical properties of epoxy glass powder mica tapes J and K were tested respectively, and their tensile strength S along the length direction was measured. t-J =179N / 10mm, S t-K =136N / 10mm, the test method is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles";

[0059] (2) Using a universal mechanical testing machine, epoxy glass powder mica tapes J and K were stretched along the length direction at a tensile stress of F = 100N / 10mm. After stabilization, the corresponding strain value D was measured. t-J =5.7%, D t-K =4.0%;

[0060] (3) Epoxy glass powder mica tapes J and K were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c-J =79MPa, S c-K =60MPa; obtain the slope V of the compressive stress-strain curve slope-J =24, V slope-K =39, the test method is in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics";

[0061] (4) Epoxy glass powder mica tapes J and K were stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine was used to compress them with a compressive stress of P = 12 MPa. After stabilization, the corresponding strain value D was measured. c-J =50%, D c-K =28%;

[0062] (5) According to the following formula, the evaluation parameters for measuring the wrapping characteristics of epoxy glass powder mica tapes J and K are calculated as P TAPE-J =52.2, P TAPE-K =26.5. TAPE-J >P TAPE-K, indicating that the better the performance of epoxy glass powder mica tape J in wrapping the generator stator coil, the better the macroscopic performance of the wrapped product. Through the comparative experimental study of actual winding parts, impregnation resin treatment and curing molding, it was found that the coil cross-section of the parts obtained by epoxy glass powder mica tape J has a smaller difference in thickness between the long and short sides, softer edges and corners, better absorption and spreadability of impregnation resin, that is, better wrapping characteristics, proving that the calculation results of this project are highly accurate.

[0063]

[0064] In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.16.

Claims

1. A method for evaluating the wrapping characteristics of epoxy glass powder mica tape facing the stator coil, characterized in that: The following steps are involved: (1) The mechanical properties of epoxy glass powder mica tape were tested and its tensile strength S along the length direction was measured. t ; (2) Using a universal mechanical testing machine, stretch the epoxy glass powder mica tape along the length direction with a tensile stress F. After stabilization, measure the corresponding strain value D t ; (3) The epoxy glass powder mica tape was stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. The compressive stress-strain curve was then tested to obtain the compressive strength S c And obtain the slope V of the compressive stress-strain curve slope ; (4) The epoxy glass powder mica tape is stacked in multiple layers in the thickness direction, with the number of stacked layers being 50. Then, a universal mechanical testing machine is used to compress it with a compressive stress P. After stabilization, the corresponding strain value D is measured. c ; (5) According to the following formula, calculate the evaluation parameter P of the wrapping characteristics of epoxy glass powder mica tape TAPE , P TAPE The larger the value, the better the performance when wrapping the generator stator coil, and the better the macroscopic performance of the product after wrapping: In the formula, x, y, a, and R are constants, which are: x=92, y=0.96, a=6.8, b=0.112, and R=18.

16.

2. The evaluation method according to claim 1, characterized in that: The test method for tensile strength in step (1) is carried out in accordance with GB / T 1040.1-2018 "Determination of tensile properties of plastics Part 1: General principles".

3. The evaluation method according to claim 1, characterized in that: The test method in step (3) is carried out in accordance with GB / T 1448-2005 "Test method for compression properties of fiber reinforced plastics".

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