A rapid method for determining the failure mechanism of corona-resistant enameled wire

Abstract

The invention relates to the technical field of enameled wire production, and in particular to a method for quickly judging the failure mechanism of a corona-resistant enameled wire. The judgment method comprises the following steps: S1, selecting a corona-resistant enameled wire to be judged; a detection solution consisting of salt, water and phenolphthalein; S2, placing the corona-resistant enameled wire to be judged in the detection solution and performing a leakage point test, wherein the leakage point test comprises the following steps: S21, energizing the corona-resistant enameled wire to be judged; S22, after energizing, observing reddened leakage points on the corona-resistant enameled wire to be judged; and S23, judging the failure mechanism of the corona-resistant enameled wire to be judged based on the reddened leakage points: if there are two reddened leakage points, the failure mechanism of the corona-resistant enameled wire to be judged is electrical breakdown failure; if there are three or more reddened leakage points, the failure mechanism of the corona-resistant enameled wire to be judged is corona breakdown failure; and if there are no reddened leakage points, the insulation performance of the corona-resistant enameled wire is qualified. The judgment method can quickly and accurately judge the failure mechanism of the corona-resistant enameled wire, and has the advantages of easy operation and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of enameled wire production, and in particular to a method for quickly judging the failure mechanism of a corona-resistant enameled wire. Background Art

[0002] Variable-frequency motors (VFMs) are widely used in home appliances, new energy, and AC variable-speed applications due to their energy-saving, high-efficiency, and user-friendly features. The power supply used by VFMs features extremely high frequencies and rapidly varying voltages. During operation, this increases capacitance loss and heat generation, which can damage the insulating film of the enameled wire inside the motor. This can lead to contact between adjacent wires, causing interturn breakdown and motor failure. Therefore, testing the performance of the enameled wire is essential for adjusting manufacturing parameters.

[0003] Compared with ordinary motors, the enameled wire used in variable frequency motors is corona-resistant enameled wire. The failure mechanisms (causes) of corona-resistant enameled wire include electrical breakdown failure and corona breakdown failure. Electrical breakdown failure is characterized by increasing the voltage at a certain rate until breakdown (breakdown failure) or the time it can withstand at a certain voltage (voltage withstand) through electrical breakdown testing; corona breakdown failure is characterized by the time the enameled wire can withstand at a specific pulse voltage, temperature, frequency and rising edge time through corona resistance testing, which is characterized by the corona resistance time.

[0004] During the enameled wire production process, different failure mechanisms correspond to different process parameter adjustments, such as paint film thickness, degree of curing, and the proportion of corona-resistant paint. However, although electrical breakdown failure and corona breakdown failure have different characterization methods, the failure characteristics of electrical breakdown failure and corona breakdown failure are relatively similar. In actual processes, the failure mechanism of variable frequency motors is still difficult to distinguish. Therefore, it is of great significance to study the method for determining the failure mechanism of variable frequency motors. Summary of the Invention

[0005] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a method for quickly judging the failure mechanism of corona-resistant enameled wire. The method can quickly and accurately judge the failure mechanism of corona-resistant enameled wire and has the advantages of easy operation and low cost.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A method for quickly determining the failure mechanism of corona-resistant enameled wire is provided, comprising the following steps:

[0008] S1. Selecting a corona-resistant enameled wire to be judged, wherein the corona-resistant enameled wire to be judged includes a corona-resistant enameled wire after an electrical breakdown test and a corona-resistant enameled wire after a corona breakdown test; preparing a detection solution, wherein the detection solution is composed of salt, water, and phenolphthalein;

[0009] S2. Place the corona-resistant enameled wire to be determined into a detection solution and perform a leakage test on the wire. The leakage test comprises the following steps:

[0010] S21: energizing the corona-resistant enameled wire to be determined;

[0011] S22: After the power is turned on for a certain period of time, observing the red leak point on the corona-resistant enameled wire to be determined;

[0012] S23: Determine the failure mechanism of the corona resistant enameled wire to be determined based on the reddening leakage points: if there are two reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is electrical breakdown failure; if there are three or more reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is corona breakdown failure; if there are no reddening leakage points, the insulation performance of the corona resistant enameled wire is qualified.

[0013] The working principle of the above-mentioned rapid judgment method of the failure mechanism of corona-resistant enameled wire is:

[0014] For electrical breakdown failure, the electrical breakdown test is performed when voltage is applied to the enameled wire. As the voltage increases, the insulating paint film fails and breaks down at locations where the insulating paint film is thin or where defects are concentrated, forming a closed loop. This closed loop causes two leaks on the enameled wire. The conductors at the two leaks interact with the test solution. The phenolphthalein in the test solution acts as an indicator, causing the solution in contact with the conductor to produce two red flow rates.

[0015] Regarding the realization of corona breakdown, when the high-frequency voltage is applied during the corona resistance test, on the one hand, local discharge will be generated on the surface, which will aggravate its electrical aging; on the other hand, the skin effect generated by the high-frequency voltage can increase the rotor resistance, resulting in increased heat generation of the motor, which aggravates thermal aging. Under the combined effect of complex electrical and thermal aging, the corona-resistant enameled wire fails, and eventually it has more than three leakage points. The conductors at more than three leakage points react with the detection solution. The phenolphthalein in the detection solution acts as an indicator, which causes the solution in contact with the conductor to produce more than three red flow rates.

[0016] For the corona-resistant enameled wire, the insulation performance is qualified. Since the enameled wire is not damaged, no red leakage points will be produced. Based on this, it can be judged that the enameled wire is qualified.

[0017] In some embodiments, in S1, the salt is dissolved in the water and the phenolphthalein, and the mixed clear solution is the detection solution.

[0018] In some embodiments, the concentration of salt in the detection solution is 1 g / L to 3 g / L.

[0019] In some embodiments, the concentration of phenolphthalein in the detection solution is 20 g / L to 35 g / L.

[0020] In some embodiments, in S2, the corona-resistant enameled wire is subjected to an electrical breakdown test and a corona breakdown test separately, and the corona-resistant enameled wire after the electrical breakdown test and the corona-resistant enameled wire after the corona breakdown test are respectively subjected to leakage point tests.

[0021] In some embodiments, in S21 , the voltage used when powering on is 11V to 13V.

[0022] In some embodiments, in S21 , the power-on time is 50s to 70s.

[0023] In some embodiments, the electrical breakdown test is performed by a breakdown voltage test or a withstand voltage test.

[0024] In some embodiments, the corona breakdown test is a corona resistance test.

[0025] The beneficial effects of the method for quickly determining the failure mechanism of corona-resistant enameled wire of the present invention are as follows:

[0026] (1) The judgment method of the present invention places the tested corona-resistant enameled wire into a detection solution, and quickly judges whether the corona-resistant enameled wire has failed and the corresponding failure mechanism when it fails based on the red leakage points displayed in the solution. This helps the staff to adjust the relevant production process in time according to different failure mechanisms, achieve fast, accurate and timely debugging, and improve the production efficiency of the corona-resistant enameled wire.

[0027] (2) The judgment method of the present invention is simple to operate, easy to implement, and low in cost, and is suitable for large-scale production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a diagram showing the effect of the corona-resistant enameled wire that failed due to electrical breakdown in the embodiment in the detection solution.

[0029] Figure 2 This is a diagram showing the effect of the corona breakdown failure corona resistant enameled wire of the embodiment in the detection solution. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0031] Example 1

[0032] This embodiment discloses a method for quickly determining the failure mechanism of a corona-resistant enameled wire, comprising the following steps:

[0033] S1. Selecting a corona-resistant enameled wire to be judged, wherein the corona-resistant enameled wire to be judged includes a corona-resistant enameled wire after an electrical breakdown test and a corona-resistant enameled wire after a corona breakdown test; preparing a detection solution, wherein the detection solution is composed of salt, water, and phenolphthalein;

[0034] S2. Place the corona-resistant enameled wire to be determined into a detection solution and perform a leakage test on the wire. The leakage test comprises the following steps:

[0035] S21: energizing the corona-resistant enameled wire to be determined;

[0036] S22: After the power is turned on for a certain period of time, observing the red leak point on the corona-resistant enameled wire to be determined;

[0037] S23: Determine the failure mechanism of the corona resistant enameled wire to be determined based on the reddening leakage points: if there are two reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is electrical breakdown failure; if there are three or more reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is corona breakdown failure; if there are no reddening leakage points, the insulation performance of the corona resistant enameled wire is qualified.

[0038] The function and effect of the above method are: by observing the red leakage points of the corona-resistant enameled wire to be judged, the failure mechanism of the corona-resistant enameled wire to be judged can be accurately judged. The corona-resistant enameled wire that fails with electrical breakdown has two red leakage points, the corona-resistant enameled wire that fails with electrical breakdown has two red leakage points and three or more leakage points, and the corona enameled wire that fails without breakdown has no leakage points. This method can quickly judge the specific failure mechanism, which is conducive to accurate and rapid targeted adjustment of the production process of the corona enameled wire.

[0039] In this embodiment, in S1, the salt is dissolved in the water and the phenolphthalein, and the resulting clear solution is the detection solution. The ratio of salt, water, and phenolphthalein is not strictly required, as long as a clear detection solution can be prepared.

[0040] In this embodiment, the salt concentration in the detection solution is 1 g / L.

[0041] In this embodiment, the concentration of phenolphthalein in the detection solution is 20 g / L.

[0042] In this embodiment, in S2, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test. The corona-resistant enameled wire after the electrical breakdown test and the corona breakdown test are then subjected to separate leakage point tests. Specifically, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test, and then to separate leakage point tests, to fully understand the failure mechanism of the corona-resistant enameled wire.

[0043] In this embodiment, in S21, the voltage used when power is turned on is 11V.

[0044] In this embodiment, in S21 , the power-on time is 50 seconds.

[0045] In this embodiment, the electrical breakdown test is performed by a breakdown voltage test or a withstand voltage test. Specifically, the test voltage selection and sample preparation are selected with reference to the GB / T4074.5-2008-T standard.

[0046] In this embodiment, the corona breakdown test is performed by a corona resistance test. Specifically, the corona resistance test parameters are selected with reference to the GB / T21707-2018 standard, such as voltage, frequency, temperature, rise time, etc.

[0047] Example 2

[0048] This embodiment discloses a method for quickly determining the failure mechanism of a corona-resistant enameled wire, comprising the following steps:

[0049] S1. Selecting a corona-resistant enameled wire to be judged, wherein the corona-resistant enameled wire to be judged includes a corona-resistant enameled wire after an electrical breakdown test and a corona-resistant enameled wire after a corona breakdown test; preparing a detection solution, wherein the detection solution is composed of salt, water, and phenolphthalein;

[0050] S2. Place the corona-resistant enameled wire to be determined into a detection solution and perform a leakage test on the wire. The leakage test comprises the following steps:

[0051] S21: energizing the corona-resistant enameled wire to be determined;

[0052] S22: After the power is turned on for a certain period of time, observing the red leak point on the corona-resistant enameled wire to be determined;

[0053] S23: Determine the failure mechanism of the corona resistant enameled wire to be determined based on the reddening leakage points: if there are two reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is electrical breakdown failure; if there are three or more reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is corona breakdown failure; if there are no reddening leakage points, the insulation performance of the corona resistant enameled wire is qualified.

[0054] The function and effect of the above method are: by observing the red leakage points of the corona-resistant enameled wire to be judged, the failure mechanism of the corona-resistant enameled wire to be judged can be accurately judged. The corona-resistant enameled wire that fails with electrical breakdown has two red leakage points, the corona-resistant enameled wire that fails with electrical breakdown has two red leakage points and three or more leakage points, and the corona enameled wire that fails without breakdown has no leakage points. This method can quickly judge the specific failure mechanism, which is conducive to accurate and rapid targeted adjustment of the production process of the corona enameled wire.

[0055] In this embodiment, in S1, the salt is dissolved in the water and the phenolphthalein, and the resulting clear solution is the detection solution. The ratio of salt, water, and phenolphthalein is not strictly required, as long as a clear detection solution can be prepared.

[0056] In this embodiment, the salt concentration in the detection solution is 3 g / L.

[0057] In this embodiment, the concentration of phenolphthalein in the detection solution is 35 g / L.

[0058] In this embodiment, in S2, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test. The corona-resistant enameled wire after the electrical breakdown test and the corona breakdown test are then subjected to separate leakage point tests. Specifically, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test, and then to separate leakage point tests, to fully understand the failure mechanism of the corona-resistant enameled wire.

[0059] In this embodiment, in S21, the voltage used when power is turned on is 13V.

[0060] In this embodiment, in S21, the power-on time is 70s.

[0061] In this embodiment, the electrical breakdown test is performed by a breakdown voltage test or a withstand voltage test. Specifically, the test voltage selection and sample preparation are selected with reference to the GB / T4074.5-2008-T standard.

[0062] In this embodiment, the corona breakdown test is performed by a corona resistance test. Specifically, the corona resistance test parameters are selected with reference to the GB / T21707-2018 standard, such as voltage, frequency, temperature, rise time, etc.

[0063] Example 3

[0064] This embodiment discloses a method for quickly determining the failure mechanism of a corona-resistant enameled wire, comprising the following steps:

[0065] S1. Selecting a corona-resistant enameled wire to be judged, wherein the corona-resistant enameled wire to be judged includes a corona-resistant enameled wire after an electrical breakdown test and a corona-resistant enameled wire after a corona breakdown test; preparing a detection solution, wherein the detection solution is composed of salt, water, and phenolphthalein;

[0066] S2. Place the corona-resistant enameled wire to be determined into a detection solution and perform a leakage test on the wire. The leakage test comprises the following steps:

[0067] S21: energizing the corona-resistant enameled wire to be determined;

[0068] S22: After the power is turned on for a certain period of time, observing the red leak point on the corona-resistant enameled wire to be determined;

[0069] S23: Determine the failure mechanism of the corona resistant enameled wire to be determined based on the reddening leakage points: if there are two reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is electrical breakdown failure; if there are three or more reddening leakage points, the failure mechanism of the corona resistant enameled wire to be determined is corona breakdown failure; if there are no reddening leakage points, the insulation performance of the corona resistant enameled wire is qualified.

[0070] The function and effect of the above method are: by observing the red leakage points of the corona-resistant enameled wire to be judged, the failure mechanism of the corona-resistant enameled wire to be judged can be accurately judged. The corona-resistant enameled wire that fails with electrical breakdown has two red leakage points, the corona-resistant enameled wire that fails with electrical breakdown has two red leakage points and three or more leakage points, and the corona enameled wire that fails without breakdown has no leakage points. This method can quickly judge the specific failure mechanism, which is conducive to accurate and rapid targeted adjustment of the production process of the corona enameled wire.

[0071] In this embodiment, in S1, the salt is dissolved in the water and the phenolphthalein, and the resulting clear solution is the detection solution. The ratio of salt, water, and phenolphthalein is not strictly required, as long as a clear detection solution can be prepared.

[0072] In this embodiment, the salt concentration in the detection solution is 2 g / L.

[0073] In this embodiment, the concentration of phenolphthalein in the detection solution is 30 g / L.

[0074] In this embodiment, in S2, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test. The corona-resistant enameled wire after the electrical breakdown test and the corona breakdown test are then subjected to separate leakage point tests. Specifically, the corona-resistant enameled wire is subjected to both an electrical breakdown test and a corona breakdown test, and then to separate leakage point tests, to fully understand the failure mechanism of the corona-resistant enameled wire.

[0075] In this embodiment, in S21, the voltage used when power is turned on is 12V.

[0076] In this embodiment, in S21 , the power-on time is 60 seconds.

[0077] In this embodiment, the electrical breakdown test is performed by a breakdown voltage test or a withstand voltage test. Specifically, the test voltage selection and sample preparation are selected with reference to the GB / T4074.5-2008-T standard.

[0078] In this embodiment, the corona breakdown test is performed by a corona resistance test. Specifically, the corona resistance test parameters are selected with reference to the GB / T21707-2018 standard, such as voltage, frequency, temperature, rise time, etc.

[0079] Judgment effect verification

[0080] The corona-resistant enameled wire with known electrical breakdown failure was used to test its failure mechanism according to the judgment method of Example 1, and the following results were obtained: Figure 1 The effect of the corona-resistant enameled wire in the test solution after the electric breakdown test is shown in the figure. Figure 1 As can be seen in the figure, there are two red flow rates and two leakage point bubbles. It can be seen that the judgment method of Example 1 can accurately judge the electrical breakdown failure mechanism.

[0081] Electrical breakdown failure

[0082] A corona-resistant enameled wire with known corona breakdown failure was used to test its failure mechanism according to the judgment method of Example 1. Figure 2 As shown in the figure, the effect of the corona breakdown failure of the corona resistant enameled wire in the test solution after the electrical breakdown test was obtained. Figure 2 As can be seen in the figure, there are multiple red flow rates and about 15 leakage bubbles. It can be seen that the judgment method of Example 1 can accurately judge the corona breakdown failure mechanism.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for quickly determining the failure mechanism of corona-resistant enameled wire, characterized by: Including the following step, S1. Selecting a corona-resistant enameled wire to be judged, wherein the corona-resistant enameled wire to be judged includes a corona-resistant enameled wire after an electrical breakdown test and a corona-resistant enameled wire after a corona breakdown test; preparing a detection solution consisting of salt, water and phenolphthalein; S2. Place the corona-resistant enameled wire to be determined into a detection solution and perform a leakage test on the wire. The leakage test comprises the following steps: S21: energizing the corona-resistant enameled wire to be determined; S22: After the power is turned on for a certain period of time, the number of red leak points on the corona-resistant enameled wire to be determined is observed; S23: Determine the failure mechanism of the corona-resistant enameled wire to be determined based on the number of red leakage points: if there are two red leakage points, the failure mechanism of the corona-resistant enameled wire to be determined is electrical breakdown failure; if there are three or more red leakage points, the failure mechanism of the corona-resistant enameled wire to be determined is corona breakdown failure; if there are no red leakage points, the insulation performance of the corona-resistant enameled wire is qualified.

2. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: In the step S1, the salt is dissolved in the water and the phenolphthalein, and the mixed clear solution is the detection solution.

3. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 2, wherein: In the detection solution, the concentration of salt is 1 g / L to 3 g / L.

4. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 3, wherein: In the detection solution, the concentration of phenolphthalein is 20 g / L to 35 g / L.

5. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: In S2, the two corona-resistant enameled wire samples are subjected to an electrical breakdown test and a corona breakdown test respectively, and the corona-resistant enameled wire sample after the electrical breakdown test and the corona-resistant enameled wire sample after the corona breakdown test are subjected to a leakage point test respectively.

6. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: In the above-mentioned S21, the voltage used when power is turned on is 11V to 13V.

7. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: In the above-mentioned S21, the power-on time is 50s to 70s.

8. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: The electrical breakdown test is performed in a breakdown voltage test or a withstand voltage test.

9. The method for quickly determining the failure mechanism of a corona-resistant enameled wire according to claim 1, wherein: The corona breakdown test is a corona resistance test.

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