SU1282027A1 - Method of contactless measuring of parameters of cylindrical specimens - Google Patents

Abstract

This invention relates to electrical measuring technology. The purpose of the invention is to expand the functionality by increasing the number of measured parameters. It is achieved by the fact that in the method of contactless measurement of the parameters of cylindrical samples (CC), the electromotive force (EMF) of the measuring coil with the center and the phase between the EMF of the measuring coils with and without the center is measured. The amplitude and phase of the relative magnetic flux (MP) and the magnitude of the generalized parameter are determined. The transverse relative magnetic permeability and longitudinal electrical conductivity are determined. Then calculate the relative MP. The description of the invention provides mathematical relationships between measured values. The invention can be used for non-destructive testing of electrical and magnetic parameters of conductive products. 3 il. Q S (L

Description

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The invention relates to electrical measuring technology and can be used for non-destructive testing of electrical and magnetic parameters of conductive products.

 invention - the expansion of the functionality:; s opportunities by increasing the number of measured parameters.

Figure 1 shows a diagram of the device for implementing the method; figure 2 is a graph of the dependence of the tangent of the phase angle between the threads in the product outside it from the generalized parameter X; on fng.Z - dependence of the amplitude of the flow D on the generalized parameter X.

The device (Fig. 1) contains a Helmholtz coil 1, used as a source of a uniform transverse magnetic field, in which a conductive sample 2, a measuring coil 3, a coil 4 is placed

mutual inductances, voltmeters 5- and 6, faa, meter 7, ammeter 8, generator of sinusoidal signals 9, rheostat 1C.

The graph (figure 2) expresses the dependence of tg ×, (the angle between the flows of luF on the value of X

tg4, -

 ,

1, l4 2 | d so8Ch, - () (1)

X ,, u3

where Ер and ЕО are the emf due to the flux Ф if respectively, R is the radius of the product, the magnetic constant; Sj is the longitudinal specific electrical conductivity and the frequency of the alternating magnetic field.

The expression for the form factor in the case of a round measuring coil 3 has the form

one

D 2 (R / a)

G1 1

/ GTSaTO, (3)

where a is the average radius of the i measuring coil 3, x is the distance from

center of the product to the middle of the measuring coil.

The graph (FIG. 3) expresses the dependence of the amplitude of the specific normalized magnetic flux on the magnitude of the generalized parameter X

IJ) l / (i4-A) -2 (1 + A) Acos f, + (f.

(1-L +2 (1-A)

I cos4 -. (V | n (4)

15

.thirty

35

40

The determination of the electrical and magnetic parameters of the conductive samples is carried out as follows.

The generator 9 sets the frequency of the exciting current, the value of which is controlled by the rheostat 10 and recorded by ammeter 4, the EMF E is measured by the voltmeter 5, and measured by the voltmeter 6 E. E. The phase angle between these EMFs is measured by a phase meter. By the formula C i), the angle of displacement between the flows D and φ or between the corresponding emfs at a known / is determined.

The magnitude of the angle H from the graphical dependence (Fig. 2) determines the value of the generalized parameter X, from which the amplitude of the specific normalized magnetic flux is determined from the graph (Fig. 3). After that, using formula (A), find the transverse relative magnetic permeability of the product P-g. Substituting the value of f into formula (2), determines the longitudinal specific electrical conductivity of the product:

Z

(five)

& {

 M .. x) R

Claims (1)

Invention Formula Contactless measuring method parameters of cylindrical samples, including the excitation in the product of eddy currents by an alternating magnetic field created by the excitation coil and applied perpendicular to the axis of the product, recording changes in the electromagnetic field using a measuring coil and measuring the EMF of the measuring coil without a product with expanding the functionality by increasing the measured parameters, measuring the EMF of the measuring coil with the product and the phase between the EMF the measuring coils with and without the product, then the measured amplitude and phase relate to it. magnetic flux and the value of the generalized parameter, followed by the determination of the transverse relative magnetic permeability and longitudinal specific electrical conductivity, and the relative magnetic flux is found by the formula . . And P -..-% f I - (1, g -  Re 282027 Where F F - p F - 6 A j .p o relative magnetic flux; transverse relative magnetic permeability of the product, magnetic flux penetrating the measuring coil in the presence of the product magnetic flux penetrating the coil without an article J function, connecting the geometrical dimensions of the measuring coil, the product and the distance between them; phase angle between streams. 8 GO FSH.Z