JPS6186663A - Method for measuring dielectric breakdown strength between layers of coil - Google Patents

Abstract

PURPOSE:To make it possible to easily judge the dielectric breakdown strength between the layers of a coil, by preliminarily providing a minute electrode apparatus, which has a pair of electrodes communicated with the air layers between coil inner layers, in a primary coil and calculating the dielectric breakdown strength between the electrodes. CONSTITUTION:A minute electrode apparatus 11 is preliminarily embedded in a primary coil 4 and this coil 4 is cast along with an iron core 1 and a secondary coil 2 by an insulating material. Voltage is applied between the electrodes of this apparatus 11 through lead wires 14 to measure the dielectric breakdown strength between the electrodes 13 within a space part 17. Because the space part 17 and an air layer are set to the same vacuum degree by a communication hole 16, the dielectric breakdown strength of the air layer can be known from that between electrodes 13. Further, the dielectric breakdown strength between the layers of the coil can be also calculated from said dielectric breakdown strength. By this method, the measurement of the optimum dielectric breakdown strength between the layers of the coil can be easily performed.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for measuring the interlayer dielectric breakdown strength of a coil, and particularly to a method for measuring the interlayer dielectric breakdown strength of a coil cast with an insulating material. [Prior Art] Fig. 3 is a sectional view showing a conventional cast-molded electrical device, and Fig. 7 is a sectional view of the main part of Fig. 3, in which a secondary coil 2 is wound around an iron core l. . A primary coil is provided on the outer periphery of this secondary coil through a molded portion 3a. - A molded portion 3b is formed on the outer periphery of the second coiler. A primary terminal 3 connected to a secondary coil and a secondary terminal 6 connected to a secondary coil λ are attached to the outside of this molded part jb. For example, the secondary coiler is composed of a copper wire 7, an insulating coating layer t covering the copper wire 7, and an interlayer insulating paper interposed between the secondary coil q layers. Furthermore, there is an air layer 10 in which air remains between the layers of the second coil. The cast electric device is constructed as described above. When the -next terminal jVC voltage is applied, a voltage is also applied between the layers of the -next coiler, and depending on the degree of vacuum of the air layer lO,
- A partial discharge occurs between the layers of the next coil q via the air layer IO. Therefore, it is important to know the relationship between the degree of vacuum of the air layer 10 and the dielectric breakdown strength. It has become more important than non-electrical devices in producing cast-molded electrical devices with excellent electrical properties. [Problems to be Solved by the Invention] Conventional electrical devices with injection coils have not been evaluated as being able to measure the dielectric breakdown strength in the air layer 10 formed between the 20 layers of the secondary coil. , air F・n/
I don't know the vacuum degree of θ and the dielectric breakdown strength value at that time, so I need to establish the manufacturing conditions for manufacturing a cast-molded electrical device, and what is the resistance between the layers of the secondary coil and the secondary coil? There were problems in that it was not possible to establish design conditions for edge fracture strength, and in some cases, cast-molded electrical devices with poor electrical properties were manufactured. This invention was made in order to solve this problem, and it is possible to easily determine the dielectric breakdown strength between the coil layers, which greatly contributes to the production of cast-molded electrical devices with excellent electrical properties. The purpose is to obtain a method for measuring interlayer dielectric breakdown strength. [Means for solving the interlayer dielectric breakdown strength] The method for measuring the interlayer dielectric breakdown strength of a coil according to the present invention is as follows:
A microelectrode device having l pairs of electrodes that communicates with two empty layers between the layers of the coil is embedded in the coil in advance, and then the coil is cast with an insulating material to form a cast electric device.Firstly, the electrodes are The dielectric breakdown strength between the electrodes is measured by applying pressure between them, and the dielectric breakdown strength between the layers of the coil is calculated from this dielectric breakdown strength. [Function] In this invention, the space between the 1 pairs of electrodes is communicated with the air layer, and the vacuum level is the same as that of the 9 air layers between the vL electrodes. By measuring the dielectric breakdown strength between the electrodes, the dielectric breakdown strength of the air layer can be determined, and from this dielectric breakdown strength, the interlayer dielectric breakdown strength of the coil can be calculated. [Example] Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is an enlarged view of the main parts of FIG. - Microelectrode devices rfAf, ll are embedded in multiple locations within the coil. This microelectrode device // is composed of a pair of electrodes /J, a lead B/4' for applying a voltage to the electrode 13, and an insulator 20 provided on the edge of the electrode 13. The insulator θ is composed of an edge 1 and an insulating plate /g sandwiching the insulating tube 1. The l pair of electrodes /J has a protrusion 15 formed at its tip, m, 41i t , 7
It is supported by P and edge plate /g so that the distance between them is maintained at one foot. A communication hole /A is formed in the upper part of the insulation cylinder 1, and the space 1 inside the insulation cylinder 16 is connected through this communication hole 16.
7 and an air layer 10 in the primary coil are communicated with each other. The above-mentioned microelectrode device // is embedded in advance in the secondary coil q, and this secondary coil q is the iron core l. By being cast with an insulating material together with the secondary coil 2, the mold part, ? a, Casting city with Jb. A prototype of the air device is completed. In addition, as for the absolute material, one having a viscosity of roooooocp or less is suitable. If the viscosity is higher than this, the mold part 3a. There is a risk that bubbles may remain in the Jb or casting defects may occur. Next, we will explain the procedure for measuring the interlaminar failure strength of a -order coiler.

【explain. First, electrode 1 of the microelectrode device /'/ embedded in the primary coiler of the cast electric device as described above.
A voltage is applied between 3 through the lead wire 1, and the space/
Measure the dielectric breakdown strength between rtt and th/3 within 7. Space part 17 and air)%10 have the same degree of vacuum due to the communicating hole /A. The dielectric breakdown strength of the air layer 1O can be determined from the dielectric breakdown strength between the electrodes 13. Furthermore, from this dielectric breakdown strength, the degree of vacuum can be determined from the dielectric breakdown strength of the primary coil layer [)] using Paschen's law, so the degree of vacuum in the air layer 10 of the primary coil layer after casting is optimal. It is possible to establish manufacturing conditions for cast electrical devices such that: In addition, in the above embodiment, minute i'r and ti are placed in the primary coil.
Although the cast electric device for dielectric breakdown strength measurement in which the device // is embedded has been described, it goes without saying that the invention can also be applied to a secondary coil λ. [Effects of the Invention] As explained above, the coil layer f[i′le
According to the edge fracture strength p-'F- measurement method, by embedding a microelectrode device ρ that communicates with the air layer inside the coil in the coil, it is possible to measure the insulation broken line strength between the layers of the coil, which was previously unknown. ? Now you can easily know, 71
1. The effect in obtaining an excellent cast-molded electrical device is great.

[Brief explanation of drawings]

Figure 2 is an enlarged sectional view of the main part of Figure 1, Figure 3 is a sectional view of a conventional example, and Figure 9 is a sectional view of a conventional example. FIG. -・-Secondary coil (coil), Ja+, 7b@'+Mall)' f13, 17 @・-Secondary coil (coil),
t00@empty layer, //...microelectrode device, /J...electrode, /4...communication hole, coO...insulator. In each figure, the same reference numerals indicate the same or similar parts. Banknote 1

Claims (2)

[Claims] (1) After embedding a microelectrode device having a pair of electrodes in a coil so as to communicate with the air space between the layers of the coil, the coil is cast with an insulating material to form a cast electric device, and then A voltage is applied between the pair of electrodes to measure the dielectric breakdown strength between the electrodes, and the dielectric breakdown strength between the layers of the coil is calculated from this dielectric breakdown strength. Strength measurement method. (2) The microelectrode device includes a pair of electrodes and an insulator provided around the pair of electrodes and having a communication hole communicating with the outside. Method for measuring interlayer dielectric breakdown strength of coils.