RU2592727C1 - Method to determine relative magnetic permeability of ferromagnetic components - Google Patents

Abstract

FIELD: measurement technology.

SUBSTANCE: invention can be used for nondestructive determination of relative magnetic permeability of parts made of ferromagnetic material. This invention consists in the fact that during induction of a magnetic field by inductor 2, its magnetomotive force is measured by sensor 6 and amplitude of magnetic induction on the opposite ends of magnetic poles of inductor B_ind and in gap B_surf between them; the value of relative magnetic permeability of ferromagnetic part is determined with the help of the following ratio:

EFFECT: higher accuracy and speed of determining relative magnetic permeability.

1 cl, 2 dwg

Description

The invention relates to the field of measuring technology of magnetic quantities and can be used for non-destructive determination of the relative magnetic permeability of parts made of their ferromagnetic material.

The prior art method for measuring the magnetic permeability of cylindrical ferromagnetic conductors, characterized in that the alternating current generator is connected to the primary winding of a step-down transformer, the magnetizing current is determined by frequency f, the voltage drop across the reference resistor is measured, and the studied a cylindrical conductor of radius r with specific conductivity σ, a drop is measured in the middle of the conductor pressure on the site with a length of 1 m, calculate its resistance Z and determine the magnetic permeability by the ratio (Patent RU 2255346, IPC G01R 33/12, 1988):

The disadvantage of this method is that the determination of magnetic permeability requires the implementation of electrical contact, stringent requirements for the form factor of the test sample and obtaining the average value of the relative magnetic permeability of the entire test sample.

Closest to the proposed known technical solution as a prototype is a method of measuring the magnetic permeability of ferromagnetic materials of rod samples, which is characterized in that they induce a magnetic flux formed by the magnetomotive force of the inductor in the form of a solenoid, into the working cavity of which the sample to be studied is placed, and the intensity is controlled and the configuration of the magnetic field by acting on the test sample by switching sections of the inductor solenoid, each schuyusya magnetic permeability and magnetic permeability according to the relative length of the inductor and parts thereof (Patent RU 2022292, IPC G01R 33/12, 1988).

The disadvantage of the prototype is that the apparent permeability depends on the form factor of the test sample, the need to place the sample in the working cavity of the inductor, the sensitivity of the ballistic measurement method from the electromagnetic and geometric characteristics of the electromagnetic measuring circuit, including the sample itself.

An object of the invention is to increase the efficiency of measuring actions for non-destructive determination of the relative magnetic permeability of parts made of ferromagnetic material.

The technical result of the invention is that the accuracy and efficiency of determining the relative magnetic permeability of parts made of ferromagnetic material is increased.

The essence of the invention lies in the fact that, in addition to the well-known and general essential action, characterized in that the magnetic flux generated by the magnetomotive force of the inductor is induced in the ferromagnetic parts, in the proposed method for determining the relative magnetic permeability of the ferromagnetic parts, the investigated part is placed outside the working cavity of the inductor and measurements are made the amplitudes of the magnetic inductions in the selected zones at the magnetization poles of the inductor and in the selected zones between the set of poles with the opposite magnetization corresponding to the applied magnetomotive force of the magnetic field, and determine the relative magnetic permeability from the relation:

где K - градуировочный корреляционный коэффициент,

where K is a calibration correlation coefficient,

The _{individual control} - value of the magnetic field in the selected zone in the outbound pole inductor magnetizing flux in _dressing - the value of the magnetic field in a selected region between the poles of the inductor

The novelty of the invention lies in the fact that in the proposed method for determining the magnetic permeability of ferromagnetic parts, the investigated part is located outside the working cavity of the inductor, the amplitudes of the magnetic inductions are measured in the selected zones at the magnetization poles and in the selected zones between the set of poles with opposite magnetization, corresponding to the applied magnetizing force of the magnetic field , and determine the relative magnetic permeability from the ratio:

где K - градуировочный корреляционный коэффициент, В_инд - значение индукции магнитного поля в выбранной зоне у полюса индуктора исходящего намагничивающего потока, В_пов - значение индукции магнитного поля в выбранной зоне между полюсами индуктора с противоположной намагниченностью, соответствующей приложенной магнитодвижущей силе индуктора, что обеспечивает повышение точности и оперативности определения относительной магнитной проницаемости деталей, выполненных из ферромагнитного материала.

where K - calibration correlation coefficient, V _ind - value of the magnetic field in a selected area near the pole inductor outgoing magnetizing flux in the _dressing - the value of the magnetic field in a selected region between the poles of the inductor with opposite magnetization corresponding inductor appended magnetomotive force, which provides increased accuracy and efficiency of determining the relative magnetic permeability of parts made of ferromagnetic material.

The functional diagram of a device that implements, as an example, the proposed method for determining the relative magnetic permeability, is shown in FIG. 1, a circuit diagram of an example of a technical implementation of the proposed method is presented in FIG. 2. In FIG. 1 and 2 are indicated:

1 - measurement object - ferromagnetic test piece;

2 - magnetic inductor;

3 - inductor magnetic circuit;

4 - magnetic induction sensor in the selected area at the pole of the inductor of the outgoing magnetizing flux;

5 - magnetic induction sensor in the selected area between the poles of the inductor with opposite magnetization;

6 - sensor magnetizing (magnetomotive) force;

7 - field lines of the magnetic field of the inductor, forming a magnetic flux;

8 - controller;

9 - personal computer;

10 - source of electrical energy;

11 - windings of a magnetic inductor.

A device that implements the proposed method for determining the relative magnetic permeability of ferromagnetic parts, works as follows.

The electric power source 10 generates an electric current that flows through the windings 11 of the magnetic inductor 2 and generates a magnetic field in a known manner, part of the power lines 7 of which are shown in FIG. 2 dashed lines. The required intensity and dynamics of the generated magnetic field is obtained by controlling the current flowing through the windings 11, which ensures the excitation of the magnetomotive force of the magnetic inductor 2. In the prototype, the magnetomotive force of the magnetic inductor is set by changing the number of turns 11 on the magnetic circuit 3, which cannot provide high accuracy and the efficiency of determining the magnetic permeability of the test ferromagnetic part 1 due to the fact that in the composite core inside the solenoid (3) and outside it (1) is Magnetic cores of various forms of factors, electromagnetic properties and relative positions of magnetic cores are held in view of non-magnetic gaps between the magnetic cores. In the proposed method for determining the relative magnetic permeability of ferromagnetic parts 1, the excitation of the magnetomotive force F _{µ is} carried out automatically using a controller 8, controlled by a personal computer 9, and a magnetomotive force sensor 6, which favorably distinguishes the claimed method in comparison with the prototype according to the criterion of accuracy and efficiency.

Further, with the help of sensors 4 and 5 of magnetic induction, operations (actions) are carried out to measure magnetic induction at the magnetic poles of the inductor B _ind and in the interval between poles with opposite magnetization B _pov, respectively. Since the measurements of the magnetic induction B are carried out at fixed values of the magnetomotive force F _{µ of the} inductor 2, the measurement of magnetic induction at the magnetic poles of the inductor B _ind and between the poles with the opposite magnetization B _pov allows for the first time to quickly and accurately determine the relative magnetic permeability of the measured object 1 using the mathematical relation:

where K is a calibration correlation coefficient that takes into account the structural features of the location of the magnetic induction sensors 4 and 5 relative to the magnetic poles of the magnetizing inductor 2, as well as the dynamic parameters of the magnetic field change and the ohmic resistance of the ferromagnetic measured part 1.

Known in the prototype actions on material magnetic quantities in determining the magnetic permeability of the material are based on measuring the amount of electricity (with a short-term current pulse), proportional to the magnetic permeability. The value of the measured amount of electricity is fixed by the first largest deviation (the so-called ballistic rejection) of the moving part (arrow) of the measuring device (ballistic galvanometer). Those. in the prototype, the apparent pulsed magnetic permeability is set in accordance with the dynamic parameters of the electromagnetic measurement circuit, sensitive both to the form factor of the sample, its location relative to the inductor’s solenoid, and to the electrical conductivity of the sample, which makes the method not versatile and time-consuming.

The industrial feasibility of the invention is justified by the fact that it uses the nodes and elements known in the analogue and prototype for their intended purpose. In 2014, the applicant organization made a working sample of the device that implements the claimed method for determining the relative magnetic permeability of ferromagnetic parts.

The positive effect of the use of the invention is that due to the fact that the magnetic field is measured from the free surface of the test sample at the selected parameters of the excitation current of the inductor in the areas near the magnetizing poles and in the selected area between the opposite poles, the universality of the method is achieved and is ensured expanding the dynamic range for determining the relative magnetic permeability with the possibility of determining the heterogeneity of permeability in a localized the place of the part in different directions on the surface, oriented in the direction of the inductor field, in addition, the absence of the need for close contact of the poles of the inductor with the surface of the part under study provides an increase of not less than 15-20% in the efficiency of determining the relative magnetic permeability of parts made of ferromagnetic material.

Claims (1)

A method for determining the relative magnetic permeability of ferromagnetic parts, based on the fact that the magnetic flux generated by the magnetomotive force of the inductor is induced in the ferromagnetic parts, characterized in that the amplitudes of the magnetic inductions are measured in the selected zones at the magnetization poles and in the selected zones between the set of poles with opposite magnetization, the corresponding applied magnetomotive force of the magnetic field, and determine the relative magnetic permeability from the ratio:

Where K - calibration correlation coefficient, B _Ind - value of the magnetic field in the selected zone in the outbound pole inductor magnetizing flux in _dressing - the value of the magnetic field in a selected region between the poles of the inductor.

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