JP4712730B2 - Pinhole test method and wire pulling device - Google Patents

Description

  The present invention relates to a pinhole test method for detecting a pinhole in an insulation coating in a conductive wire provided with an insulation coating, and a lead wire tensioning device used for carrying out the pinhole test method.

If damage (pinhole) such as a hole or a flaw occurs in the insulation coating of the conducting wire, there is a risk of leakage or the like, so it is necessary to detect the insulation coating damage in advance. As this pinhole test method, a test solution prepared by adding 5 to 10 drops of a phenolphthalein solution in which 3% of phenolphthalein is mixed in ethanol to 0.2% strength saline is prepared. It is well known to apply a DC voltage by immersing a conductor to be tested that has been heat-treated at a specified temperature without bending or stretching, and applying a DC voltage with the conductor as the negative electrode and the test solution as the positive electrode (JIS C3003). Enamel copper wire and enamel aluminum wire test method). Thus, if there is a pinhole in the insulation coating, reddish purple streaks (collection of small bubbles) are generated in the test solution, so that the presence of the pinhole can be confirmed.
On the other hand, as another test method, in Patent Document 1, when forming a coil by winding a conductive wire around an iron core or the like of an armature, the conductive wire is guided by a guide connected to a voltage detector equipped with a power source, and insulated. An invention of a coating inspection apparatus is described in which an alarm circuit is activated by forming a closed loop comprising a power source, a conductor, a guide, and a voltage detector when the coating is damaged and conduction is conducted with the guide. Patent Document 2 describes an invention of an insulation diagnostic device that diagnoses a coil end insulating film of a motor electrical winding by impedance measurement. In either case, a current is leaked to the outside of the insulation coating by applying a voltage to the conducting wire.

JP-A-6-313786 Japanese Patent Laid-Open No. 9-163685

  However, in any of the above conventional test methods, since no excessive force is applied to the insulating coating or the insulating coating is not stretched at all, pinholes hidden in the insulating coating, that is, scratches and It does not lead to detection of a place where there is a high possibility that a pinhole will occur in the future in a place where the coating thickness is uneven (hereinafter, this place is referred to as “latent part”). Therefore, when a conducting wire that has passed the test is bent or a coil or the like is formed, a pinhole may occur in the latent portion.

  Therefore, the present invention makes it possible to detect not only normal pinholes but also pinholes in latent portions, and has excellent pinhole test methods with excellent reliability, and wire tension suitable for carrying out the test methods. It is intended to provide a device.

In order to achieve the above object, the invention described in claim 1 is a pinhole test method in which a voltage is applied to a conductive wire having an insulation coating, and a current leaking outside the insulation coating through a pinhole in the insulation coating is detected. Then, the conductor is previously pulled in the length direction and stretched at a predetermined ratio, and then a voltage is applied to detect a current leaking outside the insulating coating.
In addition to the object of claim 1, the invention described in claim 2 immerses the stretched wire in a test solution made of a saline solution in which a phenolphthalein solution is dropped in order to properly perform the pinhole test. The current leaking into the test solution is detected by applying a voltage between the conductor and the test solution.
In addition to the object of the first or second aspect, the third aspect of the present invention is such that the ratio of extending the conductive wire is 3% in order to effectively reveal the pinhole in the latent portion.

In order to achieve the above object, the invention described in claim 4 is a wire pulling device used in the pinhole test method according to any one of claims 1 to 3, wherein the fixing portion can fix one end of the wire. And a drum capable of winding a conducting wire fixed to the fixing portion, and a tension operation unit capable of fixing the other end of the conducting wire and pulling the conducting wire in the length direction and extending at a predetermined ratio. It is characterized by this.
According to a fifth aspect of the present invention, in addition to the object of the fourth aspect, in order to easily perform the pulling operation of the conducting wire, the pulling operation portion includes a circular portion at least partially, A structure comprising a rotating member capable of fixing the other end of the conducting wire and capable of pulling the conducting wire in the length direction along the circumferential surface of the circular portion by rotating at a predetermined angle, and an operation lever capable of rotating the rotating member. It is a thing.

According to the first aspect of the present invention, not only normal pinholes but also pinholes in latent portions can be detected and detected, so that the reliability of the pinhole test is improved.
According to the second aspect of the invention, in addition to the effect of the first aspect, the pinhole test can be properly performed.
According to the third aspect of the present invention, in addition to the effect of the first or second aspect, the pinhole in the latent portion can be effectively manifested by applying the stress most to the insulating coating.
According to the fourth aspect of the present invention, even a long conductive wire can be set compactly without taking up space, and can be accurately stretched at a predetermined ratio. Moreover, since a winding wrinkle is produced by winding on a drum, it is possible to immerse the lead wire after tension in the test solution as it is, leading to a reduction in labor related to the pinhole test.
According to invention of Claim 5, in addition to the effect of Claim 4, pulling of conducting wire can be performed by simple operation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory view showing an example of a wire tension device (hereinafter simply referred to as “tensile device”) used in the pinhole test method of the present invention. A pair of drums 4a and 4b and a pulling operation unit 5 are provided. Here, the conductor 6 having a length of 5 m, which is the same as the JIS standard, is the subject of the test.
First, the fixing portion 3 is a rod body that is erected on the test table 2 and is fixed to one end 6a of the conducting wire 6 at the same height as a horizontal tangent that is in contact with the drums 4a and 4b from above. The drums 4a and 4b are Predetermined in the front-rear direction (with the right side in FIG. 1 (A) as the front) in a posture in which the shaft centers are parallel to each other by the support rods 7 that have circular shafts having the same diameter and are erected on the test bench 2. It is supported in a non-contact manner with the test table 2 at intervals. Further, as shown in FIG. 1 (B), flanges 8, 8,... Are provided circumferentially at equal intervals in the axial direction on the peripheral surfaces of the drums 4a, 4b. Guide grooves 9, 9.

The tension operation unit 5 is pivotally mounted on the test table 2 around the axis parallel to the axis of the drums 4a and 4b behind the fixed unit 3 and is connected to the end of the semicircular circular portion. 6 has a rotating member 10 capable of fixing the other end 6b of the motor 6, and an operation lever 11 fixed to a plane on the rotation center side of the rotating member 10. The rotating member 10 is rotated by 90 ° in the left rotation direction in FIG. 1 (A) where the operation lever 11 faces in the vertical direction by engagement of stoppers (not shown) with the test table 2 side. It can rotate between the position of the dotted line. However, since the weight 12 is coupled to the center of the circular portion of the rotating member 10 and hangs downward from the front side of the rotating member 10, the rotating member 10 is normally moved by the weight 12, and the operation lever 11 is in a normal state. It is urged to the position of the solid line in the vertical direction.
Here, the rotating member 10 is formed with a diameter in which half of the circumferential length of the circumferential surface is 3% (15 cm) of the length (5 m) of the conducting wire 6.

  A method of performing a pinhole test using the tension device 1 configured as described above will be described. First, one end 6a of the conducting wire 6 is fixed to the fixing portion 3, and after being drawn horizontally on the drums 4a and 4b as it is, the conducting wire 6 is wound around the peripheral surface of the front drum 4b and folded back to form the drum 4b. , 4a is wound around the peripheral surface of the drum 4a on the rear side, and folded forward. After the winding of the conducting wire 6 between the drums 4a and 4b is repeated a plurality of times for each guide groove 9, the other end 6b of the conducting wire 6 finally turned back from the drum 4b is fixed to the upper end of the rotating member 10. To do. Therefore, the conducting wire 6 can be stretched between the fixed portion 3 and the rotating member 10 via the drums 4a and 4b in a state where there is no extension or slack. Since the enamel film of the conductive wire 6 is not damaged by a slight rubbing, there is no possibility that a pinhole is generated even if it is wound around the drums 4a and 4b.

  Next, in the pulling operation unit 5, the rotating member 10 is rotated 90 degrees in the left rotation direction in FIG. Then, as shown by a two-dot chain line in FIG. 1A, the conducting wire 6 is pulled in the length direction by a half circumference (15 cm) of the rotating member 10 and is extended as a whole. This stretch of 3% gives the most stress to the enamel that is the insulation coating (the region where the strain between the molecular bonds is maximized). A pinhole occurs in the latent part.

  Thereafter, the operation lever 11 is returned to the original vertical position by the pulling operation unit 5 to return the rotating member 10 to the position of FIG. 1, the extension of the conducting wire 6 is released, and the conducting wire 6 is detached from the fixing unit 3 and the rotating member 10. . Thereafter, in accordance with the test method of JIS standard C3003 described above, the conductor 6 is heat-treated, and then immersed in a test solution in which a phenolphthalein solution is dropped into a saline solution. What is necessary is just to detect a pinhole by the method of applying the direct-current voltage and detecting the electric current which leaks outside the insulating film. This makes it possible to detect not only pinholes originally present in the insulating coating, but also pinholes generated in the latent portion due to stretching by the tensioning device 1. The evaluation of the pinhole test results is judged by the number of pinholes generated (number of reddish purple stripes), but the required level such as “0” or “3 or less” depending on the product type or size. Is different.

As described above, according to the pinhole test method of the above embodiment, the conductor 6 is previously pulled in the length direction and stretched at a predetermined ratio, and then a voltage is applied to detect a current leaking outside the insulating coating. As a result, not only normal pinholes but also pinholes in latent portions can be detected and detected, so that the reliability of the pinhole test is improved.
In particular, by immersing the stretched lead wire 6 in a test solution made of a saline solution in which a phenolphthalein solution is dropped and applying a voltage between the lead wire 6 and the test solution, a current leaking into the test solution is detected. The pinhole test can be properly performed.
Further, by setting the ratio of extending the conducting wire 6 to 3%, the most stress is applied to the insulating coating, and pinholes in the latent portion can be effectively revealed.

And in the said pinhole test method, the fixing | fixed part 3 which can fix the one end 6a of the conducting wire 6, the drum 4a, 4b which can wind the conducting wire 6 fixed to the fixing | fixed part 3, and the other end 6b of the conducting wire 6 Can be fixed, and by using the tension device 1 provided with the tension operation unit 5 that can stretch the lead wire 6 in the length direction and extend at a predetermined rate, the long lead wire 6 can be compact without taking up space. It can be set and stretched exactly 3%. Moreover, since the curl is formed by winding it around the drums 4a and 4b, the lead wire after the tension can be immersed in the test solution as it is, which leads to a reduction in labor related to the pinhole test.
In particular, here, the pulling operation portion 5 can be fixed to the end of the circular portion with the other end 6b of the conducting wire 6 and rotated by 90 ° to pull the conducting wire 6 along the circumferential surface of the circular portion in the length direction. By constituting the member 10 and the operation lever 11 capable of rotating the rotating member 10, the conductor 6 can be pulled with a simple operation.

In the above embodiment, the extension of the conducting wire is 3%. However, the ratio is not limited to this ratio, and another ratio such as 5% may be adopted depending on the type of enamel. Moreover, the length of a conducting wire can also be changed suitably.
Therefore, the rotation angle of the rotating member of the pulling operation unit may be changed in accordance with the expansion ratio, and the diameter can be arbitrarily changed. Further, the rotating member is not limited to a semicircular shape and may be a disk shape, and the rotation urging may use another urging means such as a torsion spring instead of the weight, or the urging means may be omitted. . Furthermore, it is not necessary to arrange the tension operation section on the same side as the fixed section, and it can be disposed on the opposite side of the fixed section with the drum interposed therebetween.

On the other hand, the diameter of the drum can be appropriately changed according to the length of the conducting wire. Of course, the diameter is not limited to two, and the conducting wire can be wound using only one circular or oval drum. In the case of two, it may be a semicircular shape having only a winding portion. Further, it is conceivable that the circular drum is rotatably supported in order to minimize the influence on the conductor.
And, in order to stretch the wire accurately without stretching or slack, at least one of the fixed part, drum, and tension operation part is screwed with a support base and a long hole, or a screw feed mechanism is adopted. The fixing position may be adjustable in the front-rear direction of the test table.

In addition, the pinhole test method is not limited to the form in which the phenolphthalein solution is dropped in the test solution composed of the saline solution as in the above-described form, but other diagnosis and inspection devices as presented in the background art above. It is also possible to use.

It is explanatory drawing of a conducting wire tension | pulling apparatus, (A) shows a side surface, (B) shows a front, respectively.

Explanation of symbols

  1 .... Conductor pulling device 2 .... Test stand 3 .... Fixing part 4a, 4b ... Drum 5 .... Tensioning operation part 6 .... Conducting wire 9, ... Guide groove 10 .... Fixing member 11. ・ Operating lever.

Claims (5)

A pinhole test method for detecting a current leaking to the outside of the insulation coating through a pinhole in the insulation coating by applying a voltage to a conductor provided with the insulation coating,
A pinhole test method characterized by detecting a current leaking to the outside of the insulating coating by applying a voltage after previously pulling the conducting wire in the length direction and extending it at a predetermined rate.   The stretched lead wire is immersed in a test solution made of a saline solution in which a phenolphthalein solution is dropped, and a voltage is applied between the lead wire and the test solution to detect a current leaking to the test solution. The pinhole test method according to claim 1.   The pinhole test method according to claim 1 or 2, wherein a ratio of extending the conducting wire is 3%.   It is a conducting wire tension | pulling apparatus used for the pinhole test method in any one of Claim 1 thru | or 3, Comprising: The fixing | fixed part which can fix the end of conducting wire, and the drum which can wind the said conducting wire fixed to the fixing | fixed part And a tension operation unit that can fix the other end of the conducting wire and can pull the conducting wire in the length direction and extend it at a predetermined ratio.   The pulling operation part includes a circular part at least in part, and can fix the other end of the conducting wire to the circumferential surface of the circular part, and the longitudinal direction of the conducting wire along the circumferential surface of the circular part by rotation at a predetermined angle. The lead wire tensioning device according to claim 4, comprising: a rotary member that can be pulled in a straight line; and an operation lever that can rotate the rotary member.

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