SU1451625A1 - Method of determining the number of spot damages of wire insulation - Google Patents

Abstract

This invention relates to electrical measuring technology. The purpose of the invention is to increase the efficiency of control. The wire 3 from the sending unit 2 is guided through the guide rollers 1 through the sensor 4 with an electrically conducting fluid. By varying the voltage applied to the test wire, defects with different area are recorded, and the defects are separated depending on the geometric dimensions. The control efficiency is achieved due to the differentiation of the screening both in the manufacture of wires and in the manufacture of electro1: chemical products, i Cp. f-ly, 1 ill. S

Description

The invention relates to electrical engineering and can be used in the manufacture of wires with a film electrically insulating coating.

The purpose of the invention is to increase the efficiency of control due to the differentiated sorting of wires according to the size of the defects.

The drawing shows a block diagram of a device that implements the method.

The device comprises guide rollers 1, a returning unit 2 with a test wire 3, a sensor 4 with an electrically conductive liquid, a power supply unit 5 connected to a receiving unit 2 and a voltage regulator b, a receiving unit 7, a counter 8 of the number of defects connected to a defect indicator 9 and a sensor 4

The essence of the method is as follows.

Mercury is used as an electrically conductive liquid that does not wet the insulating coating of the wire. Since mercury does not wet the insulation, in the presence of defects with sufficiently small sizes, a meniscus of mercury is formed. The capillary pressure arising from the formation of the meniscus does not allow mercury to come into contact with the wire, close the circuit and turn on the counter for the number of closures and the indicator of the presence of defects. This situation is realized for all defects for which the relation ^P oL> ^P f ^P E 'O) where P ^ = cC (1 / R, + l / R ₂ ) ^_ capillary pressure;

¢ 4 - coefficient of surface tension

R ί, R ₂ niya; are the main radii of visas of the surface of mercury; ^p " - hydrostatic tical pressure; P = EE ^g / 2 E - - pressure created by electric

by forces;

£ is the dielectric constant of vacuum;

E is the electric field intensity.

The value decreases with increasing linear dimensions of the defect and, starting from a certain value of the linear size, inequality (1) is violated. At 15, the mercury touches the wire, the electrical circuit closes, and the meter registers a defect. When implementing the prototype method, the potential difference between mercury and the wire is constant, therefore, the value is also constant, and therefore there is no possibility of separation of defects in size and, therefore, it is impossible to conduct differentiated 25 rejection of wires.

When implementing the proposed method, tests can be carried out simultaneously on several sections of wire, with defects of various sizes being separated at each section. Such separation is possible due to the fact that when the potential difference between the electrically conductive liquid and the test wire changes, the pressure changes. By increasing the potential difference, and, therefore, increasing P _E , it is possible to violate inequality (1) and short circuit the defects with fewer linear dimensions.

Differentiated sorting of the pipeline is carried out as follows.

First, the wire is pulled through an electrically conductive liquid at the lowest voltage. If the meter registers shorts, then the insulation of the wire has defects of relatively large sizes. If no defects are found, then such a wire can be used 5θ. However, if increased requirements are imposed on the insulation of wires, then the wire is passed through an electrically conductive liquid, having previously created a large potential difference between the wire and the electrically conductive liquid. In this case, defects of a relatively smaller size can be detected, since the additional electrostatic pressure creates the conditions for circuit closure through minor damage. Consistently increasing the voltage, it is possible to separate the insulation defects by their sizes.

The method can be modified using several wet contacts, each of which creates its own potential difference between the wire and the electrically conductive liquid that does not wet the insulation, therefore, there is no need to stretch the wire many times.

The dependence of the size of defects on voltage can be determined either empirically - by preliminary calibration of devices, or by calculation.

The device operates as follows.

The wire 3 from the sending unit 2 through the guide rollers 1 is pulled through the sensor 4 with an electrically conductive liquid into the receiving unit 7. With a film insulation thickness of 0.25 μm, when block 5 creates a potential difference d q> = 1.6 V, insulation defects are recorded with diameter over 16 microns. Using a device 6 for changing the voltage to ds / = 4.5 V, defects with a diameter of more than 4 μm, etc., are recorded.

The method allows to separate the defects of the film insulation of the wires according to their geometric dimensions, which

1451625 ⁴ provides for their differentiated sorting both in the production of wires and in their use for the manufacture of electrical and technical products.

Claims (2)

Claim 10 I. Method for determining the number of point damage to the insulation of the wire, in which the test wire is pulled through an electrically conductive liquid, non-wetting coating 15 wires, and the wire and the electrically conductive liquid are connected to a limited current source with a limited current counter, the number of faults and an indication of the presence of defects, and the number of defects is judged by the frequency of operation of the meter, characterized in that, in order to increase the efficiency of control due to differentiated sorting of wires according to the size of the defects, the voltage between the test wire and the electrically conductive liquid is set depending on the specified minimum 3θ of the size of the detected defect. 2. The method according to claim 1, characterized in that the measurements are carried out on several sections of the wire, 35 with defects of various sizes being recorded on each.