JP2004347609A - Coil flaw inspecting device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To specify a flaw position in a coil by nondestructive inspection. <P>SOLUTION: A conductive inspection liquid 3 mixed with isopropyl alcohol in a fluorinated inert liquid is supplied gradually into an inspection vessel 11, a voltage is impressed between an electrode 21 and the coil 2, and the position of the coil flaw is specified based on a height of an inspection liquid level measured by a liquid level sensor 16 in the time point when conductivity is detected between the electrode 21 and the coil 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coil flaw inspection apparatus and method.

  The coil is used for various electric devices such as a rotating electric machine such as a motor or a generator, or a transformer. By the way, if the coil used in such an electric device is damaged, it may cause insulation deterioration or short circuit.

  Conventionally, as a method of inspecting a wound in such a coil, for example, there is a pinhole test using a saline solution. In this method, the measurement target coil connected to the DC positive electrode and the DC negative electrode is immersed in a water tank containing saline and phenolphthalene. This is a method of finding flaws by bubbles generated from the area or red discoloration of the solution.

  However, this inspection method can identify the position of a flaw when air bubbles are generated, but has a problem in that the position of the flaw cannot be confirmed only by red discoloration of the solution.

  In addition, this inspection method is a destructive test that deteriorates the film of the coil because the solution used for the inspection itself is corrosive, and even if it does not detect a flaw, the coil after inspection is used as a product as it is. There was a problem that I could not do it.

  In particular, if the installation time is long, cracks are generated due to the deterioration of the coil coating due to the solution, which may be mistaken for the original scratch, so there is also a problem that the measurement time is limited to about 20 seconds and the detection power is low. .

  Therefore, an object of the present invention is to provide a coil flaw inspection apparatus capable of specifying a flaw position and a method thereof, and in particular, to provide a coil flaw inspection apparatus capable of non-destructive inspection and a method thereof. To provide.

  The object of the present invention is achieved by the following configurations.

  (1) A conductive test liquid in which an alcohol-based solution is mixed with a fluorine-based inert liquid, a test tank in which a coil to be tested is placed and the test liquid is supplied, and the test liquid is supplied to the test tank. Test liquid supply means, a liquid level measuring means for measuring the liquid level of the test liquid supplied to the test tank, an electrode installed in the test tank, the electrode and the coil to be inspected. The conductivity detection means for detecting the conductivity between the, and the liquid level height measurement means at the time when the conductivity detection means has detected the conductivity between the electrode and the coil to be inspected, A coil flaw detection device for specifying a flaw position of the coil to be inspected from a liquid level of a test liquid.

  (2) A coil to be inspected is placed in an inspection tank, and a conductive inspection liquid obtained by mixing an alcohol-based solution with a fluorine-based inert liquid is supplied into the inspection tank. A voltage is applied between the coil to be inspected and an electrode provided in the inspection tank while measuring a voltage of the test liquid at the time when conductivity between the coil to be inspected and the electrode is detected. A coil flaw inspection method characterized by specifying a position of a coil flaw from a surface height.

  According to the present invention, while supplying a conductive test liquid in which fluorinated inert liquid is mixed with isopropyl alcohol to the test tank by the test liquid supply means, the conductive detection means sets a gap between the coil to be tested and the electrode. Since the conductivity is detected, the coil damage position specifying means determines the position of the coil damage from the liquid surface height measured by the liquid surface height measurement means at the time when it is detected that there is conductivity, The position of the coil flaw can be reliably specified by a simple operation. In addition, since a solution in which isopropyl alcohol is mixed with a fluorine-based inert liquid is used as the test liquid, there is no need to repeat processing such as cleaning after the test.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a configuration of a coil flaw inspection device (hereinafter, referred to as an inspection device) to which the present invention is applied, and FIG. 2 is a block diagram illustrating a main configuration of the inspection device.

  The inspection apparatus 1 supplies an inspection tank 11 for accommodating a coil 2 to be inspected, an inspection liquid tank 12 containing an inspection liquid 3 to be supplied to the inspection tank 11, and the inspection liquid 3 from the inspection liquid tank 12 to the inspection tank 11. Supply facility 13 for the test, a liquid discharge facility 14 for returning the test liquid 3 in the test tank 11 to the test liquid tank 12, a liquid control device 15 for controlling the supply and discharge of the test liquid 3, a test in the test tank 11 A liquid level sensor 16 for measuring the height of the liquid surface of the liquid 3; a test electrode 21 provided in the test tank 11; an insulation meter 22 for measuring the insulation between the test electrode 21 and the coil 2 to be tested; It comprises a personal computer 23 for displaying and the like, and an operation panel 25.

  Here, the inspection tank 11 and the personal computer 23 are arranged above the inspection table 26, and the inspection liquid tank 12 and the liquid control device 15 are arranged below the inspection table 26. As shown in FIG. 2, the liquid level sensor 16 and the liquid control device 15 are supplied with power required for operation from a power supply 28, and the personal computer 23 is also separately supplied with power.

  The inspection tank 11 is provided with an inspection electrode 21 and a liquid level sensor 16 inside. The test electrode 21 is completely insulated from the outside of the test tank 11 by the test tank 11, and is set so as to be in a position where the test electrode 3 is in contact with the test liquid 3 when the test liquid 3 is at the minimum level, as described later. Here, the coil 2 to be inspected is surrounded.

  On the other hand, the liquid level sensor 16 is, for example, a float type, and the float 17 floats above the test liquid 3 and detects the height of the liquid level based on its position. At least a portion of the float 17 and the liquid level sensor 16 which may come into contact with the test liquid 3 is made of an insulating material.

  The liquid level detected by the liquid level sensor 16 is transmitted to the personal computer 23 and the liquid control device 15 via the I / O interface 24.

  The test liquid tank 12 is a tank for storing the test liquid 3, and is provided with an intake / exhaust valve 19 to prevent the pressure in the tank from suddenly changing when the test liquid is sent or the test liquid is discharged from the test tank 11. Have been. Note that an opening may be provided only in place of the intake / exhaust valve 19.

  The liquid supply facility 13 is composed of a liquid feed pipe 31, a pump 32, and a control valve 33, and gradually supplies the test liquid 3 in the test liquid tank 12 to the test tank 11 according to a command from the liquid control device 15.

  The liquid discharge facility 14 includes a liquid filter 41, a pipe 42, and a valve 43. Here, since the inspection tank 11 is located above the inspection table 26 (see FIG. 1), the inspection liquid 3 in the inspection tank 11 is returned to the lower inspection liquid tank 12 by opening the valve 43.

  Since the liquid discharge device 14 is provided with the liquid filter 41, dust and the like generated in the inspection tank 11 are filtered by the liquid filter 41, so that the test liquid can be reused.

  Note that the valve 43 may be a manual valve or an electromagnetic valve that opens and closes according to a command from the liquid control device 15.

  The insulation meter 22 applies a predetermined voltage between the inspection electrode 21 and the coil 2 to be inspected, and measures a current value flowing between the inspection electrode 21 and the coil 2 to be inspected. The measurement result is transmitted to the personal computer 23. Here, the inspection electrode 21 is set to the positive electrode, and the coil under test 2 is set to the negative electrode.

  The liquid control device 15 controls the pump 32 and the control so that the liquid level of the test liquid 3 supplied to the test tank 11 rises at a predetermined speed based on the measured value of the liquid level from the liquid level sensor 16. The valve 33 is controlled.

  The personal computer 23 measures the position of the coil flaw from the current value obtained from the insulation meter 22 and the height of the test liquid 3 obtained from the liquid level sensor 16, and specifies the position.

  The test liquid 3 is a solution obtained by mixing 7% of isopropyl alcohol, which is a conductive alcoholic solution, with a fluorine-based inert liquid that is not corrosive to the insulating-coated coil 2 and is used for cleaning electronic devices. It is.

  The operation panel 25 is for inputting start and stop of the entire inspection apparatus.

  Hereinafter, a method for inspecting coil flaws using this inspection apparatus will be described.

  First, the coil 2 to be inspected is put in a state where there is no inspection liquid in the inspection tank 11. At this time, the direction in which the inspection target coil 2 is inserted is defined as a first posture.

  When the apparatus is started by the operation panel 25, the test liquid 3 is supplied from the test liquid tank 12 to the test tank 11 at a constant flow rate, and a voltage is applied between the test electrode 21 and the coil 2 to be tested by the insulation meter 22. Is applied, and at the same time, the liquid level sensor 16 measures the liquid level of the test liquid 3 supplied to the test tank 11.

  In this state, if the coil 2 is damaged such that the insulating layer is broken, a current flows between the coil 2 and the test electrode 21 via the conductive test solution 3, and this current is It is measured by the insulation meter 22. Therefore, the conductivity is detected when the current value increases.

  Then, the position of the wound of the coil 2 is determined from the liquid level of the test liquid 3 at the time when the current is detected.

  When the conductivity is detected, the supply of the test liquid 3 is temporarily stopped, and the liquid level at that time is maintained. This is to determine the size of the flaw from the obtained current value, which will be described later in detail.

  Thereby, the position of the coil flaw in the first posture is obtained as the height of the test liquid surface.

  At this time, the area of the flaw generated in the coil 2 can be obtained from the measured current value.

  In order to determine the area of the flaw, it is determined from the current value after a lapse of a predetermined time after detecting that the current has flowed. This is because it takes time for the current value measured by the insulation meter 22 to stabilize. For example, as shown in FIG. 3, the current reaches a maximum (60 mA) at the time when the current has been detected (slightly before the lapse of 5 seconds), and then gradually decreases to 20 mA after a lapse of about 50 seconds. Between 40 and 40 mA.

  The reason why the current value decreases after the current value becomes the maximum is that the electric resistance of the test solution 3 gradually increases. This is because the concentration of the test solution 3 in the vicinity of the surface of the test electrode 21 and the flaw generation site is reduced by the chemical reaction.

  In other words, on the surface of the test electrode 21 serving as the positive electrode, oxygen and oxygen ions form a film on the surface of the test electrode 21 and refuse to receive stable electrons e. This is because, on the surface, hydrogen bubbles generated from the scratch form a film on the surface of the scratch and hinder stable emission of electrons e.

  Therefore, in the present embodiment, the area of the flaw occurring in the coil 2 is determined based on the current value at the time when 5 seconds have elapsed after the current is detected and the current is stabilized.

  The reason for measuring the current value after 5 seconds is that even if the current value at this time is measured several times, an almost stable result is obtained, and the measurement can be performed in a short time after voltage application. This is because the point where the current value is maximum at the time t has a large variation in the current value and is not suitable for the current value measurement, and after 50 seconds from the voltage application, the current value becomes unstable and the current value becomes unstable. This is because it is not suitable. Therefore, a region where 5 to 50 seconds have passed for one flaw after voltage application is a stable region suitable for current measurement.

FIG. 4 is a drawing showing the relationship between the current value A (mA) and the flaw area S (mm ² ). ing.

According to this, the relationship between the current value A (mA) and the flaw area S (mm ² ) is in a proportional relationship in which the flaw area S increases as the current value A increases, and S = kA (k is It is a proportional constant, which is “1” here.)

  The relationship between the current value and the wound area is determined by the type of coil (for example, the difference in the thickness of the coil winding, the size of the coil, or the type of motor in the case of a motor, etc.). First, the size of the coil flaw is measured in advance, and a graph as shown in FIG. 4 is created by inspecting the coil, and a proportional constant k is obtained from the created graph and prepared. Good.

  In this way, the size of the flaw when the coil flaw is generated is also detected, so that the detected flaw can be specified from its area. For example, the first wound found is the first wound.

  Note that such a scratch position is determined by a program prepared in the personal computer 23 in advance. That is, in the personal computer 23, the position of the flaw is specified from the height of the test liquid level from the liquid level sensor 16 at the time when the current value from the insulation meter 22 suddenly rises, and the flaw area is obtained from the current value after 5 seconds. Will be.

  Thereafter, the supply of the test liquid 3 which has been stopped is restarted, and when the detected current further changes, it is similarly determined that the current is damaged. The area of the flaw detected at this time is obtained by adding the area of the newly detected flaw to the previously detected flaw, and the current value is accordingly increased.

  As in the above-described case, the current value 5 to 50 seconds after the increase in the current value is used as the current value used to determine the wound area detected after the supply of the test solution is restarted. Then, by subtracting the previously detected flaw area from the flaw area obtained from the current value at that time, the flaw area detected after the supply of the test solution is resumed can be obtained.

  FIG. 5 is a diagram showing an example of an inspection result when one coil has a plurality of scratches.

  As can be seen from the figure, when the liquid level of the test liquid rises and the test liquid reaches a portion having a flaw, a current flows at that time. Thereafter, when the liquid level further rises, more current flows each time there is a flaw. As a result, the position of each flaw is determined by the level of the liquid surface, and the size of each flaw is also determined from the current value at that time.

  As described above, the inspection is performed until the inspection target coil 2 is completely immersed in the inspection liquid 3.

  After the coil 2 to be inspected is immersed in the inspection liquid 3, the valve 43 is opened to drain the inspection liquid, the attitude of the coil 2 is changed (second attitude), and the above-described inspection is performed again. Thus, the position of the flaw detected in the first posture is determined as the position of the flaw in the second posture.

  Then, after the inspection in the second posture is completed, the position of the wound in the third posture can be known by changing the posture of the coil and performing the inspection (third posture).

  In this way, the three-dimensional position of the coil flaw is determined from the flaw positions obtained from the first to third postures.

  Here, by changing the first to third postures by 90 degrees in accordance with, for example, a rectangular coordinate system, it is easy to specify a three-dimensional flaw position. Even when the angle cannot be changed by 90 degrees in accordance with the rectangular coordinate system, the position of the flaw, that is, the liquid level at the time when the flaw is detected changes between the first to third postures. In this case, the position of the flaw can be specified from the posture and the liquid level at that time.

  When a single coil has a plurality of flaws, as described above, since each flaw is specified together with its area, the position of the flaw is determined from the area of the flaw detected in each posture. .

  As described above, according to the present embodiment, the position of a coil flaw can be specified, and the test solution used for the test has no corrosiveness. It can be used as In particular, in the present embodiment, the test liquid is a solution in which isopropyl alcohol is mixed with a fluorine-based inert liquid used for cleaning electric components, and therefore, there is no need to repeat processing such as cleaning.

  In this manner, by knowing the position of the wound of the coil according to the present embodiment, it is possible to identify the cause and operation of the wound of the coil, and it is possible to repair the damaged place.

  In the present embodiment, the inspection is performed three times by changing the posture of the coil to be inspected. However, since this is for identifying a three-dimensional position, the position of a flaw in the coil from a specific direction is determined. In the case where it is necessary to understand, only one inspection may be performed.

  Further, in the present embodiment, the value of the current flowing between the inspection electrode and the coil is measured when the coil has a flaw by using an insulation meter to determine the flaw area. In this case, a device that can simply detect whether or not a current is flowing may be used instead of the insulation meter.

  In the inspection of the coil, it is possible not only to inspect the coil alone but also to inspect it in a state where the coil is assembled as a component using the coil such as a stator or a rotor of a motor.

It is a schematic diagram showing the composition of the coil flaw inspection device to which the present invention is applied. It is a block diagram showing the composition of the above-mentioned inspection device. 5 is a diagram showing a change in a current value over time when a coil flaw exists. It is the figure which showed the relationship between a current value and a flaw area. It is a drawing showing an example of an inspection result in case one coil has a plurality of flaws.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Inspection apparatus 2 ... Inspection coil 3 ... Inspection liquid 11 ... Inspection tank 12 ... Inspection liquid tank 13 ... Liquid supply equipment 14 ... Liquid discharge equipment 15 ... Liquid control device 16 ... Liquid level sensor 17 ... Float 19 ... Intake and exhaust valve 21 ... Inspection electrode 22 ... Insulation meter 23 ... PC 24 ... I / O interface 25 ... Operation panel 26 ... Inspection table 28 ... Power supply 31 ... Pipe 32 ... Pump 33 ... Control valve 41 ... Filter 42 ... Pipe 43 ... Valve

Claims (5)

A conductive test liquid obtained by mixing an alcohol-based solution with a fluorine-based inert liquid,
An inspection tank on which a coil to be inspected is placed and the inspection liquid is supplied;
Test liquid supply means for supplying the test liquid to the test tank,
Liquid level measuring means for measuring the liquid level of the test liquid supplied to the test tank,
An electrode installed in the inspection tank,
Conductivity detection means for detecting the conductivity between the electrode and the coil to be inspected,
From the liquid level of the test liquid measured by the liquid level measuring means at the time when the conductivity detecting means detects the conductivity between the electrode and the coil to be inspected, the position of the wound of the coil to be inspected is determined. Coil wound position specifying means for specifying
A coil flaw inspection device comprising: The conductivity detection means,
By applying a voltage between the electrode and the coil to be inspected, the value of a current flowing between the electrode and the coil to be inspected by detecting insulation between the electrode and the coil to be inspected is calculated. The coil damage inspection device according to claim 1, wherein the coil damage inspection device is an insulation meter for measuring.   3. The coil flaw inspection apparatus according to claim 2, further comprising flaw determining means for determining a flaw size of the coil to be inspected from the current value measured by the insulation meter. The test liquid supply means, a test liquid storage means containing the test liquid,
Test liquid sending means for sending the test liquid from the test liquid storage means to the test tank,
Test liquid return means for returning the test liquid in the test tank to the test liquid storage means,
Filtration means provided on the path of the test liquid return means,
The coil damage inspection device according to any one of claims 1 to 3, further comprising: Place the coil to be inspected in the inspection tank,
A conductive test liquid obtained by mixing an alcohol-based solution with a fluorine-based inert liquid is supplied into the test tank, and the liquid is placed in the test target coil and the test tank while measuring the liquid level of the test liquid. Voltage between the electrode and
A coil flaw inspection method comprising: identifying a position of a coil flaw from a liquid level of the test liquid at a time when conductivity between the coil to be tested and the electrode is detected.

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