阅读说明：本技术 磁极覆层缺陷的检测方法及装置 (Method and device for detecting defects of magnetic pole coating ) 是由 刘勇 李斐斐 于 2020-05-22 设计创作，主要内容包括：本申请涉及永磁电机技术领域,提供了一种磁极覆层缺陷的检测方法及装置,该检测方法包括：获取磁极覆层表面的目标测试区域对应的电流信号；根据电流信号,确定对应的缺陷信息参数；根据缺陷信息参数,确定目标测试区域是否存在缺陷。通过介电法检测磁极覆层的目标测试区域的电流信号,实现对该目标测试区域是否存在缺陷进行判断,相较于目视检查,提高了缺陷检测的准确性和检测效率；通过对磁极覆层缺陷的检测,对灌封工艺提出更高的要求,倒逼灌封工艺提升,进而提升磁极表面灌封树脂层的防护能力。(The application relates to the technical field of permanent magnet motors, and provides a method and a device for detecting defects of a magnetic pole coating, wherein the method comprises the following steps: acquiring a current signal corresponding to a target test area on the surface of the magnetic pole coating; determining corresponding defect information parameters according to the current signals; and determining whether the target test area has defects according to the defect information parameters. The current signal of the target test area of the magnetic pole coating is detected by a dielectric method, so that whether the target test area has defects or not is judged, and compared with visual inspection, the accuracy and the detection efficiency of defect detection are improved; through the detection of the defects of the magnetic pole coating, higher requirements are put forward on the encapsulation process, the inverse encapsulation process is improved, and the protection capability of the encapsulating resin layer on the surface of the magnetic pole is further improved.)

1. A method for detecting a pole coating defect, comprising:

acquiring a current signal corresponding to a target test area on the surface of the magnetic pole coating;

determining corresponding defect information parameters according to the current signals;

and determining whether the target test area has defects according to the defect information parameters.

2. The method of claim 1, wherein the obtaining a current signal of a target test area of a pole coating surface comprises:

applying a test voltage between the pole coating and a pole;

a first conductance current signal of the target test area at the test voltage is obtained.

3. The method of claim 2, wherein said determining a corresponding defect information parameter from said current signal comprises:

and determining the insulation resistance corresponding to the target test area according to the conductance current corresponding to the first conductance current signal and the test voltage.

4. The method of claim 3, wherein said determining whether the target test area is defective based on the defect information parameter comprises:

and determining whether the target test area has defects or not according to the difference value relation between the insulation resistance and the reference insulation resistance.

5. The method for detecting defects of a magnetic pole coating as claimed in claim 4, wherein the step of determining whether the target test area has defects or not according to the relation of the difference value of the insulation resistance and the reference insulation resistance comprises the following steps:

and determining the reference insulation resistance according to the insulation resistance corresponding to the magnetic pole coating which completely covers the magnetic pole.

6. The method of claim 1, wherein the obtaining a current signal of a target test area of a pole coating surface comprises:

applying a set voltage between the pole coating and the pole; the set voltage is greater than the first breakdown voltage and less than the second breakdown voltage;

and acquiring a second conductance current signal of the target test area under the set voltage.

7. The method of claim 6, wherein said determining whether the target test area is defective based on the defect information parameter comprises:

and determining whether the target test area has defects according to the difference relation between the conductance current corresponding to the second conductance current signal and the reference conductance current.

8. The method of claim 1, wherein the obtaining a current signal of a target test area of a pole coating surface comprises:

applying an alternating voltage between the pole coating surface and the pole;

acquiring a test current signal of the target test area under the alternating voltage;

and determining corresponding defect information parameters according to the current signals, including:

determining the dielectric loss of the target test area according to the test current signal;

and determining whether the target test area has defects according to the defect information parameters comprises:

and determining whether the target test area has defects according to the dielectric loss.

9. The method for detecting the coating defect of the magnetic pole according to any one of the claims 1 to 8, characterized in that before the step of acquiring the current signal corresponding to the target test area of the surface of the magnetic pole coating, the method comprises the following steps:

manufacturing a magnetic pole coating on the surface of the magnetic pole;

and acquiring the curing time of the magnetic pole coating.

10. The method of claim 9, wherein said obtaining a curing time for said pole coating comprises:

acquiring at least one parameter of resistivity, capacitance, dielectric constant and dielectric loss of at least one test point in the magnetic pole coating in real time;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the capacitance, the dielectric constant and the dielectric loss.

11. The method of claim 9, wherein said obtaining a curing time for said pole coating comprises:

acquiring at least one parameter of resistivity, dielectric constant and dielectric loss corresponding to at least one test point in the magnetic pole coating at intervals;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the dielectric constant and the dielectric loss.

12. The method for detecting coating defects of a magnetic pole according to any one of claims 1 to 8, wherein after determining whether the target test area has defects according to the defect information parameters, the method further comprises:

and if the target test area is determined to have defects, marking the target test area.

13. An apparatus for detecting pole coating defects, comprising:

the detection component is used for acquiring a current signal of a target test area on the surface of the magnetic pole coating;

the signal conversion component is electrically connected with the detection component and is used for determining corresponding defect information parameters according to the current signals;

and the processing component is electrically connected with the signal conversion component and used for determining whether the target test area has defects according to the defect information parameters.

14. The detecting device for detecting the rotation of a motor rotor according to the claim 13, wherein the detecting component comprises a testing electrode and a set level used for being connected with a magnetic pole;

the test electrode and the set electrical average are electrically connected with the signal conversion component;

the test electrode is used for scanning the surface of the magnetic pole coating to obtain current signals corresponding to each target test area;

the test electrode is also used for forming a working voltage with a set level; the working voltage comprises a test voltage, a set voltage or an alternating current voltage.

15. The test device of claim 14, wherein the test electrode comprises: an insulating rod and a conductive contact;

the conductive contact is arranged at one end of the insulating rod;

one end of the conductive contact piece is electrically connected with the signal conversion component, and the other end of the conductive contact piece is used for being in contact with the surface of the magnetic pole coating.

16. The test device of claim 15, wherein the conductive contact is a soaked sponge.

17. The detecting device for detecting the rotation of a motor rotor as claimed in claim 15, wherein the test electrode further comprises a marking part which is sleeved on the insulating rod;

the marking component is electrically connected with the processing component and used for marking the target test area after determining that the target test area has defects.

18. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a controller, carries out a method of detecting pole coating defects according to any one of claims 1 to 12.

Technical Field

The application relates to the technical field of permanent magnet motors, in particular to a method and a device for detecting defects of a magnetic pole coating.

Background

Permanent magnet motors are known for their high efficiency and are currently the most widely used motor type in various industries. The rare earth permanent magnet is used as a magnetic pole to establish a magnetic field, and replaces a rotor excitation winding of a traditional motor.

The magnetic pole of the large permanent magnet motor is fixed by adopting a mechanical fixing mode, reinforcing materials such as glass fiber are paved on the surface after the magnetic pole is installed, and then resin is poured, so that the resin can bond and fix the magnetic pole and can play a role in sealing and corrosion prevention.

After protective glue injection of the existing magnetic pole, a muffle furnace is used for heating, so that the injected and encapsulated resin is cured, the heating time is determined by the thermal state hardness of the cured resin, and the heating process time is determined accordingly. After the glue injection is finished, the covering effect of the potting resin is checked visually, the checking is limited by objective conditions and human factors, and the covering effect cannot be evaluated accurately.

Disclosure of Invention

The application provides a method and a device for detecting the coating defects of the magnetic poles aiming at the defects in the prior art, and aims to solve the technical problems that the coating defects cannot be accurately detected and the detection efficiency is low in the prior art.

In a first aspect, the present application provides a method for detecting a pole coating defect, including:

acquiring a current signal corresponding to a target test area on the surface of the magnetic pole coating;

determining corresponding defect information parameters according to the current signals;

and determining whether the target test area has defects according to the defect information parameters.

In one possible implementation, the acquiring a current signal of a target test area of a surface of a pole coating includes:

applying a test voltage between the pole coating and a pole;

a first conductance current signal of the target test area at the test voltage is obtained.

In one possible implementation manner, the determining the corresponding defect information parameter according to the current signal includes:

and determining the insulation resistance corresponding to the target test area according to the conductance current corresponding to the first conductance current signal and the test voltage.

In a possible implementation manner, the determining whether the target test area has a defect according to the defect information parameter includes:

and determining whether the target test area has defects or not according to the difference value relation between the insulation resistance and the reference insulation resistance.

In a possible implementation manner, before determining whether the target test region has a defect according to a difference relationship between the insulation resistance and a reference insulation resistance, the method includes:

and determining the reference insulation resistance according to the insulation resistance corresponding to the magnetic pole coating which completely covers the magnetic pole.

In one possible implementation, the acquiring a current signal of a target test area of a surface of a pole coating includes:

applying a set voltage between the pole coating and the pole; the set voltage is greater than the first breakdown voltage and less than the second breakdown voltage;

and acquiring a second conductance current signal of the target test area under the set voltage.

In a possible implementation manner, the determining whether the target test area has a defect according to the defect information parameter includes:

and determining whether the target test area has defects according to the difference relation between the conductance current corresponding to the second conductance current signal and the reference conductance current.

In one possible implementation, the acquiring a current signal of a target test area of a surface of a pole coating includes:

applying an alternating voltage between the pole coating surface and the pole;

acquiring a test current signal of the target test area under the alternating voltage;

and determining corresponding defect information parameters according to the current signals, including:

determining the dielectric loss of the target test area according to the test current signal;

and determining whether the target test area has defects according to the defect information parameters comprises:

and determining whether the target test area has defects according to the dielectric loss.

In one possible implementation manner, before the acquiring the current signal corresponding to the target test area of the surface of the magnetic pole coating, the method includes:

manufacturing a magnetic pole coating on the surface of the magnetic pole;

and acquiring the curing time of the magnetic pole coating.

In one possible implementation, the obtaining the curing time of the pole coating includes:

acquiring at least one parameter of resistivity, capacitance, dielectric constant and dielectric loss of at least one test point in the magnetic pole coating in real time;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the capacitance, the dielectric constant and the dielectric loss.

In one possible implementation, the obtaining the curing time of the pole coating includes:

acquiring at least one parameter of resistivity, dielectric constant and dielectric loss corresponding to at least one test point in the magnetic pole coating at intervals;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the dielectric constant and the dielectric loss.

In a possible implementation manner, after determining whether the target test area has a defect according to the defect information parameter, the method further includes:

and if the target test area is determined to have defects, marking the target test area.

In a second aspect, the present application provides an apparatus for detecting a pole coating defect, including:

the detection component is used for acquiring a current signal of a target test area on the surface of the magnetic pole coating;

the signal conversion component is electrically connected with the detection component and is used for determining corresponding defect information parameters according to the current signals;

and the processing component is electrically connected with the signal conversion component and used for determining whether the target test area has defects according to the defect information parameters.

In one possible implementation, the detection means comprise a test electrode and a set level for connection to a magnetic pole;

the test electrode and the set electrical average are electrically connected with the signal conversion component;

the test electrodes are used for scanning the surfaces of the magnetic pole coatings which synchronously rotate along with the rotor so as to obtain current signals corresponding to each target test area;

the test electrode is also used for forming a working voltage with a set level; the working voltage comprises a test voltage, a set voltage or an alternating current voltage.

In one possible implementation, the test electrode includes: an insulating rod and a conductive contact;

the conductive contact is arranged at one end of the insulating rod;

one end of the conductive contact piece is electrically connected with the signal conversion component, and the other end of the conductive contact piece is used for being in real-time contact with the surface of the magnetic pole coating.

In one possible implementation, the conductive contact is a soaked sponge.

In one possible implementation manner, the test electrode further comprises a marking part, and the marking part is sleeved on the insulating rod;

the marking component is electrically connected with the processing component and used for marking the target test area after determining that the target test area has defects.

In a third aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a controller to implement the method for detecting a pole coating defect according to the first aspect.

The beneficial technical effects brought by the technical scheme provided by the embodiment of the application at least comprise:

according to the method for detecting the defects of the magnetic pole coating, the current signals of the target test area of the magnetic pole coating are detected through the dielectric method, so that whether the target test area has the defects or not is judged, and compared with visual inspection, the accuracy and the detection efficiency of defect detection are improved; through the detection of the defects of the magnetic pole coating, higher requirements are put forward on the encapsulation process, the inverse encapsulation process is improved, and the protection capability of the encapsulating resin layer on the surface of the magnetic pole is further improved.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a flow chart of a method for detecting a pole coating defect according to an embodiment of the present disclosure;

FIG. 2 is a flow chart of another method for detecting pole coating defects according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of a through defect of a pole coating provided by an embodiment of the present application;

FIG. 4 is a flow chart of another method for detecting a pole coating defect according to an embodiment of the present application;

FIG. 5 is a flow chart of another method for detecting defects in a pole coating according to an embodiment of the present disclosure;

FIG. 6 is a flow chart of a method for detecting a pole coating defect according to an embodiment of the present disclosure;

FIG. 7 is a schematic view of a non-through defect of a pole coating provided by an embodiment of the present application;

FIG. 8 is a graph illustrating dielectric parameters of a pole coating versus curing time according to an embodiment of the present disclosure;

FIG. 9 is a flow chart of a method for detecting a pole coating defect according to an embodiment of the present disclosure;

FIG. 10 is a connection diagram of a device for detecting defects in a pole coating according to an embodiment of the present disclosure;

FIG. 11 is a schematic view of another apparatus for detecting defects in pole coating according to an embodiment of the present disclosure;

fig. 12 is a schematic structural diagram of a test electrode of an apparatus for detecting a pole coating defect according to an embodiment of the present application.

Detailed Description

Reference will now be made in detail to the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts or parts having the same or similar functions throughout. In addition, if a detailed description of the known art is not necessary for illustrating the features of the present application, it is omitted. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is to be understood that the term "and/or" as used herein is intended to include all or any and all combinations of one or more of the associated listed items.

The inventor of the application finds that the protection glue injection of the existing magnetic pole is carried out by heating in an enclosure furnace, so that the injected encapsulating resin is cured, the heating time is determined by the thermal state hardness of the cured resin, and the heating process time is determined accordingly. After the glue injection is finished, the covering effect of the potting resin is checked by visual inspection. Objectively, the human eye has limited vision and cannot accurately observe micropores smaller than a certain size (such as smaller than 0.1 mm); and if the area of the encapsulated magnetic pole is large (such as more than 10 square meters), the operation time limit is limited, and all the areas cannot be detected one by one.

Therefore, the embodiment of the application provides a method and a device for detecting a magnetic pole coating defect, and aims to solve the above technical problems in the prior art.

The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments.

As shown in fig. 1, a method for detecting a magnetic pole coating defect provided in an embodiment of the present application includes the following steps S101 to S103:

s101, acquiring a current signal corresponding to a target test area on the surface of the magnetic pole coating.

And S102, determining corresponding defect information parameters according to the current signals.

S103, determining whether the target test area has defects according to the defect information parameters.

According to the method for detecting the defects of the magnetic pole coating, the current signals of the target test area of the magnetic pole coating are detected through the dielectric method, so that whether the target test area has the defects or not is judged, and compared with visual inspection, the accuracy and the detection efficiency of defect detection are improved; through the detection of the defects of the magnetic pole coating, higher requirements are put forward on the encapsulation process, the inverse encapsulation process is improved, and the protection capability of the encapsulating resin layer on the surface of the magnetic pole is further improved.

Note that, the pole coating in the above embodiment is a potting resin layer. In addition, the target test area of the pole coating can be determined according to the maximum area acceptable for pole coating repair, and after determining that the target test area has defects, the area is subsequently repaired in its entirety.

In one embodiment of the present application, step S101 includes: applying a test voltage between the pole coating and the pole; and acquiring a first conductance current signal of a target testing area under the testing voltage.

In one embodiment of the present application, step S102 includes: and determining the insulation resistance corresponding to the target test area according to the conductance current and the test voltage corresponding to the first conductance current signal.

In one embodiment of the present application, step S103 includes:

and determining whether the target test area has defects or not according to the difference value relation between the insulation resistance and the reference insulation resistance.

Based on the content of the foregoing embodiments, as shown in fig. 2, another method for detecting a defect in a cladding layer of a magnetic pole is provided in the embodiments of the present application, where the defect information parameter is insulation resistance, and the method includes the following steps S201 to S204:

s201, applying a test voltage between the magnetic pole coating and the magnetic pole.

S202, acquiring a first conductance current signal of a target test area under the test voltage.

And S203, determining the insulation resistance corresponding to the target test area according to the conductance current and the test voltage corresponding to the first conductance current signal.

And S204, determining whether the target test area has defects or not according to the difference value relation between the insulation resistance and the reference insulation resistance.

In this embodiment, the specific position of the through defect can be determined by using the magnitude of the insulation resistance corresponding to the conductance current detected in the target test region, thereby realizing effective detection of the magnetic pole coating.

The defect information parameter in this embodiment is an insulation resistance, and the detection of the penetration defect can be performed on the potting resin layer by using the insulation resistance. Fig. 3 schematically shows a defect in penetration of the potting resin layer, where reference numeral 1 in fig. 3 denotes the potting resin layer, and reference numeral 2 denotes a defect in penetration (i.e., complete penetration), where the defect is in a completely penetrated state or a nearly completely penetrated state, and a state in which only a thin layer of resin is adhered to the magnetic pole surface in the nearly completely penetrated state.

Specifically, the potting resin used for the magnetic pole coating is a polymer material, has a certain insulating property, and the conductive current of the potting resin is usually very small.

Wherein, the conductance current value I corresponding to the first conductance current signal between the test magnetic pole coating and the magnetic pole_sPreviously, a test voltage of U was applied between the pole coating and the pole, thereby creating an electric field between the pole coating and the pole.

Insulation resistance R corresponding to magnetic pole coating_sCan be calculated according to equation (1):

R_s＝U/I_s， (1)

when the potting resin completely covers the surface of the magnetic pole, the conductive current tested by the testing electrode on the surface of the potting resin is mainly I of the potting resin_sCorresponding insulation resistance value R_sAnd are typically large.

When there is a defect in the penetration between the potting resin and the pole or only a very thin layer of resin adheres, the measured conduction current is mainly contributed by the defect (i.e. pinhole), and therefore I_sVery large, corresponding test insulation resistance R_sIs very small, passes through R_sThe size of the target test area can be judged whether the target test area has defects or not.

Optionally, when wet electrodes are employed at the test end, this I_sThe value is further amplified and the measured R_sThe value will be smaller and the presence of defects will be more easily detected.

In this embodiment, the insulation resistance R is passed_sSignificant difference in value between through defects and no through defectsThe presence and specific location of the transfixion defect can be detected.

In one embodiment, before step S204, the method includes: and determining the reference insulation resistance according to the insulation resistance corresponding to the magnetic pole coating which completely covers the magnetic pole.

Specifically, the reference insulation resistance is an insulation resistance corresponding to when the magnetic pole coating completely covers the magnetic pole, that is, an insulation resistance corresponding to when the detection area is defect-free.

Based on the content of the foregoing embodiments, as shown in fig. 4, another method for detecting a pole coating defect is provided in an embodiment of the present application, and the method includes the following steps S301 to S305:

s301, applying a test voltage between the magnetic pole coating and the magnetic pole.

S302, acquiring a first conductance current signal of a target test area under a test voltage.

And S303, determining the insulation resistance corresponding to the target test area according to the conductance current and the test voltage corresponding to the first conductance current signal.

And S304, determining the reference insulation resistance according to the insulation resistance corresponding to the magnetic pole coating layer which completely covers the magnetic pole.

S305, determining whether the target test area has defects according to the difference value relation between the insulation resistance and the reference insulation resistance.

Step S304 may be executed before step S303, before step S302, and before step S301.

In one embodiment of the present application, step S301 includes: firstly, applying a set voltage between a magnetic pole coating and a magnetic pole; the set voltage is greater than the first breakdown voltage and less than the second breakdown voltage.

Alternatively, the first breakdown voltage is a value corresponding to a maximum voltage that can be withstood when the thickness of the potting resin is close to full penetration, and the second breakdown voltage is a value corresponding to a breakdown voltage that can be withstood when the potting resin fully covers the thickness of the pole (without defects). The set voltage causes destruction (breakdown) of the potting resin layer having a defect, i.e., a small thickness.

Then, a second conductance current signal of the target test area at the set voltage is acquired.

Optionally, the electric field generated by the set voltage between the potting resin and the magnetic pole may puncture the potting resin layer of the target test region with the defect, and at this time, the sudden change of the conductance current value corresponding to the second conductance current value signal of the region may be detected, so as to determine whether the region has the defect.

In one embodiment of the present application, step S305 includes: and determining whether the target test area has defects according to the difference relation between the conductance current corresponding to the second conductance current signal and the reference conductance current.

Alternatively, the conductance current value corresponding to the second conductance current signal may be compared with the reference conductance current, and when the target test area has a defect, the conductance current generated by the breakdown of the potting resin at the operating voltage may be much larger than the conductance current of the normal coverage area (reference conductance current).

Based on the content of the foregoing embodiments, as shown in fig. 5, an embodiment of the present application further provides a method for detecting a defect of a magnetic pole coating, where the defect information parameter is a second conduction current, and the method includes the following steps S401 to S403:

s401, applying a set voltage between the magnetic pole coating and the magnetic pole; the set voltage is greater than the first breakdown voltage and less than the second breakdown voltage.

S402, acquiring a second conductance current of the target test area under the set voltage.

And S403, determining whether the target test area has defects according to the difference relation between the second conductance current and the reference conductance current.

In the embodiment, the set voltage capable of puncturing the encapsulation resin layer with the defects is applied between the target test area and the magnetic pole, so that whether the defects exist is judged according to the conductance current of the test area, the covering effect of the magnetic pole coating can be comprehensively detected, and the detection efficiency is improved.

The above embodiments are specifically described below with specific examples: the resin thickness between the surface of the potting resin and the magnetic pole was set to 1mm, and the breakdown voltage thereof was assumed to be 20kV, i.e., the second breakdown voltage in the present embodiment, which corresponds to a completely covered (defect-free) potting resin layer. The breakdown voltage will be significantly reduced when there is a through defect or only a very thin layer of resin is attached.

Assuming that the maximum breakdown voltage value corresponding to the potting resin layer having a thickness of 0.01mm is 5kV (the first breakdown voltage in this embodiment), the set voltage between the surface of the potting resin and the magnetic pole is set to 6kV (the set voltage should not damage the intact potting resin layer) and the set voltage is between the first breakdown voltage and the second breakdown voltage so that the set voltage can breakdown the resin having a thickness of 0.01mm (defective resin) when the electrical strength is detected.

When the test electrode touches the penetrating defect or the defect that the thickness of the effective resin layer is less than 0.01mm, the test area is punctured, the corresponding conductive current is increased instantly, and whether the defect exists in the area can be judged according to the difference relation between the conductive current and the reference conductive current.

In some embodiments, a 'crack' sound is emitted while the breakdown phenomenon occurs, and a corresponding acoustic sensor and/or optical sensor is arranged to perform detection alarm, so that the position of the defect is judged.

In one embodiment of the present application, step S101 includes: applying an alternating voltage between the pole coating surface and the pole; and acquiring a test current signal of a target test area under the alternating voltage.

In one embodiment of the present application, step S102 includes: and determining the dielectric loss of the target test area according to the test current signal.

In one embodiment of the present application, step S103 includes: and determining whether the target test area has defects according to the dielectric loss.

Based on the content of the foregoing embodiments, as shown in fig. 6, another method for detecting a defect of a magnetic pole coating layer is further provided in an embodiment of the present application, where a defect information parameter in the embodiment is dielectric loss, and the method includes the following steps S501 to S504:

s501, applying alternating voltage between the surface of the magnetic pole coating and the magnetic pole.

And S502, acquiring a test current signal of a target test area under the alternating voltage.

And S503, determining the dielectric loss of the target test area according to the test current signal.

And S504, determining whether the target test area has defects according to the dielectric loss.

Specifically, in an electrode system having the potting resin surface and the magnetic pole as both electrodes, when a non-penetrating pore defect exists, the state is shown in fig. 7, reference numeral 1 in fig. 7 denotes a potting resin layer, reference numeral 3 denotes a pore defect (that is, bubbles exist in the potting resin), and the potting resin layer having the pore defect can be approximated to a series capacitor circuit. The dielectric loss tan δ of the circuit is the active power and the reactive power (P) when an alternating voltage is applied between the surface of the potting resin and the magnetic pole_{Active power}/Q_{Reactive power}) The expression is shown as formula (2):

tanδ＝1/ωCR (2)

wherein: ω 2 π f, the frequency of the power supply;

c is the equivalent capacitance of the series circuit;

r is the equivalent resistance of the series circuit.

When no pore defect exists between the electrodes, the R, C values in the equivalent circuit are all in the maximum state, and the measured dielectric loss tan δ is the minimum. When the void defect exists between the electrodes, the value of R, C in the equivalent circuit is reduced, and the measured dielectric loss tan δ is increased compared with that when the void defect does not exist.

Since the dielectric loss tan δ is related to the conductance current, the test current signal of the pole coating at the ac voltage can be detected by a dielectric method, so as to calculate the corresponding dielectric loss, for example: the dielectric loss can be directly detected by a dielectric loss analyzer. And further, judging whether the target test area has the air hole defect or not according to the change value of the dielectric loss.

In some embodiments, the conductance (i.e., active power) in the equivalent circuit will be significantly increased due to the intervention of water, and the dielectric loss tan δ is significantly increased, which is beneficial for improving the detection effect.

On the basis of the above embodiment, optionally, before step S101, the method includes:

and manufacturing a magnetic pole coating on the surface of the magnetic pole.

Specifically, before carrying out defect detection on the magnetic pole coating, the magnetic pole coating needs to be manufactured on the surface of the magnetic pole, namely, after the magnetic pole is installed, reinforcing materials such as glass fibers are paved on the surface, and then resin is poured, wherein the resin is poured to bond and fix the magnetic pole on one hand and seal and prevent corrosion on the other hand.

The curing time of the pole coating is obtained.

In the embodiment, the curing process of the resin encapsulated on the surface of the magnetic pole is monitored, so that the end point time of resin curing can be determined more objectively and accurately, and the time control of the heating process of the resin is more reasonable and scientific.

In one embodiment of the present application, a method of obtaining a curing time of a pole coating includes:

acquiring at least one parameter of resistivity, capacitance, dielectric constant and dielectric loss of at least one test point in the magnetic pole coating in real time;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the capacitance, the dielectric constant and the dielectric loss.

In this embodiment, the principle of monitoring the curing time of the resin by using the dielectric property is as follows: the dielectric properties of the material depend on its microstructure, and changes in the microstructure of the material can be reflected by the dielectric properties. The encapsulation resin is liquid micromolecule before the solidification occurs, the resin is firstly gelatinized after heating and solidification, and the molecular chain rapidly grows in the gelatinization process and rapidly becomes macromolecular gel with the molecular weight of hundreds of thousands or even millions; heating is continued, molecular crosslinking is continued until the molecular crosslinking reaction is gradually terminated at a certain period, and the encapsulating resin finally becomes a solid macromolecular substance with stable performance.

The physical state of the encapsulating resin can be reflected in real time from the state of liquid micromolecules, the state of macromolecular gel and the state of solid macromolecular substances through the change of macroscopic electrical property parameters of the encapsulating resin. During the transformation process from liquid state to gelation of the potting resin, the curve of the dielectric parameter is subjected to mutation (inflection point is generated); subsequently, as the molecular crosslinking continues until the resin becomes a solid with stable properties, the dielectric property curve gradually changes from a changing state to a smooth curve, and the curve changing process is approximately as shown in fig. 8.

In the embodiment, by monitoring the change conditions of the parameters of the resistivity rho, the capacitance C, the dielectric constant epsilon and the dielectric loss tan delta in the curing process of the potting resin in real time, the curing can be considered to be completed when the curve change of each parameter is basically stable, and the process time parameter of the resin curing is determined according to the change conditions.

Since the change curves of the resistivity ρ, the capacitance C, the dielectric constant ∈ and the dielectric loss tan δ are all stabilized when the resin is a solid material having stable properties, the resin curing process time may be monitored by using at least one of the resistivity ρ, the capacitance C, the dielectric constant ∈ and the dielectric loss tan δ.

In some embodiments, the resistivity ρ, the capacitance C, the dielectric constant ∈ and the dielectric loss tan δ can be directly measured by a dielectric loss analyzer.

Alternatively, a plurality of electrodes may be disposed on the surface of the potting resin, the plurality of electrodes may be arranged at intervals along the circumferential direction of the potting resin, and the curing process time of the resin may be determined by simultaneously monitoring at least one parameter of the resistivity ρ, the capacitance C, the dielectric constant ∈, and the dielectric loss tan δ through the plurality of electrodes.

In one embodiment of the present application, another method of obtaining a curing time for a pole coating includes:

acquiring at least one parameter of resistivity, dielectric constant and dielectric loss corresponding to at least one test point in the magnetic pole coating at intervals;

and determining the curing time corresponding to the magnetic pole coating reaching the curing end point according to at least one parameter of the resistivity, the dielectric constant and the dielectric loss.

In the embodiment, the change conditions of the resistivity rho, the dielectric loss tan delta and the dielectric constant epsilon in the resin curing process are monitored at intervals, and the curing process time parameter can be obtained by considering that the curing is finished when the data is continuously measured for 2 or 3 times and is stable. The time for spacing the measurement data needs to be set empirically or with reference to the resin cure time monitored in real time in the previous embodiment.

In one embodiment of the present application, after step S103, the method includes: and if the target test area is determined to have defects, marking the target test area.

Specifically, after a target test area with a defect is determined, the test area needs to be marked in time so as to repair the test area in a subsequent process, thereby improving the efficiency of the whole detection process.

Based on the content of the foregoing embodiments, optionally, as shown in fig. 9, an embodiment of the present application further provides a method for detecting a pole coating defect, including the following steps:

s101, acquiring a current signal corresponding to a target test area on the surface of the magnetic pole coating.

And S102, determining corresponding defect information parameters according to the current signals.

S103, determining whether the target test area has defects according to the defect information parameters.

And S104, marking the target test area if the target test area is determined to have defects.

According to the detection method of the magnetic pole coating provided by the embodiment, the target test area with the defects is detected by using a dielectric method, so that the detection efficiency and accuracy of the defects of the magnetic pole coating are improved; and the target test area with the defects is marked, so that the defects can be repaired conveniently in the follow-up process, and the preparation process period of the whole magnetic pole coating is shortened.

Based on the same inventive concept, as shown in fig. 10, an embodiment of the present application provides a device for detecting a pole coating defect, including:

a detection part 100 for acquiring a current signal of a target test area of the surface of the magnetic pole coating;

the signal conversion part 200 is electrically connected with the detection part and is used for determining corresponding defect information parameters according to the current signals;

and the processing component 300 is electrically connected with the signal conversion component and is used for determining whether the target test area has defects according to the defect information parameters.

Wherein the signal conversion part 200 may be integrated in the same controller as the processing part 300.

In one embodiment of the present application, as shown in fig. 11, the detection part 100 includes a test electrode 101 and a set level for connection with a magnetic pole; the test electrode 101 and the set electric average are electrically connected to the signal conversion part 200; the test electrodes 101 are used to scan the surface of the pole coating to obtain current signals corresponding to each target test area.

The test electrode 101 is also used for forming a working voltage with a set level; the working voltage comprises a test voltage, a set voltage or an alternating voltage, and the required voltage can be respectively provided between the magnetic pole and the potting resin when electrical strength monitoring, destructive inspection or dielectric loss detection is carried out so as to meet the detection of a current signal.

Alternatively, the set level may be a zero level, equivalent to grounding the magnetic pole.

In one embodiment of the present application, as shown in fig. 12, the test electrode 101 includes: an insulating rod 1011 and a conductive contact 1012; a conductive contact 1012 is disposed at one end of the insulating rod 1011; one end of the conductive contact 1012 is electrically connected to the signal conversion member 200, and the other end is used to contact the surface of the pole coating.

In particular, the insulating rod 1011 is made of an insulating material, and can be of an elongated tubular structure, which is convenient for hand holding. The conductive contact 1012 is electrically connected to the signal conversion part via a wire and can be connected to a set level

Alternatively, a rotatable rod (driven by a motor) may be arranged at the center of the rotor to be inspected, and the insulating rod 1011 may be mounted on the rod or attached directly to the output shaft of the motor such that the conductive contact 1012 contacts the pole coating. The rotation of the motor drives the insulating rod 1011 to rotate, thereby realizing the scanning detection of the conductive contact 1012 and the magnetic pole coating. When a defect is detected in a certain test area, the processing unit 300 may immediately instruct the motor to suspend rotation. Of course, by controlling the rotational speed of the motor, the dwell time of the conductive contacts in each target test area can be controlled.

In one embodiment, the conductive contact may be a soaked sponge. The soaking sponge can increase the humidity of the conductive contact element, so that detection signals are amplified, and the accuracy of detection results is improved. In addition, when the soaking sponge is contacted with the surface of the magnetic pole coating, the soaking sponge has certain buffering performance and is not easy to damage the magnetic pole coating.

In one embodiment of the present application, with continued reference to fig. 12, the test electrode includes a marking member 1013 in addition to the insulating rod and the conductive contact, wherein the marking member 1013 is sleeved on the insulating rod and can be fixed by bonding or bolt connection. The marking unit 1013 is electrically connected to the processing unit 300 and is used for marking the target test area after determining that the target test area has a defect.

Alternatively, the movable end of the marking member 1013 may be provided in a frame-like structure similar to the outline of the conductive contact, and the size of the movable end may be slightly larger than the outline of the conductive contact, so as to mark the test area with defects immediately after the test area is determined.

Alternatively, the marking element 1013 can be implemented using an existing marker, and the marking area of the marker can be preset and matched with the target test area where the conductive contact contacts the pole coating. After determining that the target test region has a defect, the processing component 300 sends a marking control instruction to the marker, and the marker marks the target test region after receiving the control instruction, so as to repair the region conveniently.

Based on the same inventive concept, the present application provides a computer-readable storage medium, on which a computer program is stored, and the computer-readable storage medium is characterized in that the computer program, when executed by a controller, implements the method for detecting a pole coating defect provided by the present application. Wherein the controller comprises a processing component and a signal conversion component in the detection device.

The computer readable medium includes, but is not limited to, any type of disk including floppy disks, hard disks, optical disks, CD-ROMs, and magneto-optical disks, ROMs, RAMs, EPROMs (Erasable Programmable Read-Only Memory), EEPROMs, flash Memory, magnetic cards, or fiber optic cards. That is, a readable medium includes any medium that stores or transmits information in a form readable by a device (e.g., a computer).

The computer-readable storage medium provided in the embodiments of the present application has the same inventive concept and the same advantages as the embodiments described above, and contents not shown in detail in the computer-readable storage medium may refer to the embodiments described above, and are not described herein again.

Those of skill in the art will appreciate that the various operations, methods, steps in the processes, acts, or solutions discussed in this application can be interchanged, modified, combined, or eliminated. Further, other steps, measures, or schemes in various operations, methods, or flows that have been discussed in this application can be alternated, altered, rearranged, broken down, combined, or deleted. Further, steps, measures, schemes in the prior art having various operations, methods, procedures disclosed in the present application may also be alternated, modified, rearranged, decomposed, combined, or deleted.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

In the description herein, particular features, structures, materials, or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least a portion of the steps in the flow chart of the figure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

The foregoing is only a partial embodiment of the present application, and it should be noted that, for those skilled in the art, several modifications and decorations can be made without departing from the principle of the present application, and these modifications and decorations should also be regarded as the protection scope of the present application.