RU2462729C2 - Device for measuring magnetisation curve of ferromagnetic materials - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: device has a ferromagnetic ring made from the investigated ferromagnetic material, an oscillating circuit coil and a Hall sensor. The ring is placed between poles of an electromagnet connected to a controlled direct current source. The coil is made on the ferromagnetic ring and is connected to a high-frequency generator. The Hall sensor is placed in the magnetic gap of the electromagnet. The high-frequency generator is connected to a frequency metre and the Hall sensor is connected to the input of a magnetic field strength metre.

EFFECT: high accuracy of measuring the magnetisation curve of a ferromagnetic material in a wide range of magnetic field strength variation.

1 dwg

Description

The invention relates to the physics of magnetism and can be used to remove the dependence of the magnetic susceptibility of a ferromagnet on the magnitude of the magnetic field applied to it (Stoletov magnetization curve).

It is known that a ferromagnet in the absence of a magnetic field has an initial magnetic susceptibility χ _NAV . As the magnitude of the magnetic field H increases, the magnetic susceptibility χ (H) increases, reaches a maximum χ *, and then decreases again, and in the paraprocess mode (i.e., when the magnetic induction is saturated), the product χ (Н) * Н remains maximum and practically constant, despite a further increase in the magnetic field strength against the value of H _us , which determines the saturation of magnetization [1-3].

The closest analogue of the claimed technical solution is the “Magnetic viscosity meter of ferromagnets”, known from the patent of the Russian Federation No. 2357241 of the same author, published in bulletin No. 15 dated 05/27/2009. This meter contains a ferromagnetic ring from the studied ferromagnet, partially placed between the poles of an electromagnet connected to an adjustable constant current source. An oscillating circuit coil connected to a high-frequency generator is located on this ring. To measure the magnetic field generated between the poles of the electromagnet, the meter includes a film Hall sensor placed in the magnetic gap of the electromagnet. In addition, the known device also includes a decision processor with an indicator.

The known device solves the problem of measuring the magnetic viscosity of a ferromagnet, but cannot measure its magnetic susceptibility in a wide range of magnetic field N. The disadvantage of the prototype device is that only a part of the ferromagnetic ring is placed in the magnetic field of the electromagnet, which reduces the reliability of the measurement dependences χ (Н).

The aim of the invention is to improve the accuracy of measurements of the magnetization curve of a ferromagnet in a wide range of changes in the magnetic field.

This goal is achieved in a device for measuring the magnetization curve of a ferromagnet, containing a ferromagnetic ring from the studied ferromagnet, placed between the poles of an electromagnet connected to an adjustable direct current source, an oscillating circuit coil made on a ferromagnetic ring and connected to a high-frequency generator, a film Hall sensor placed in the magnetic gap of the electromagnet, as well as a decisive processor with an indicator, characterized in that the high-frequency generator is connected ene to the measuring frequency, the film included a Hall sensor input measuring magnetic field strength, and outputs the frequency meter and measuring the magnetic field intensity included respectively to the first and second data inputs to processor decisive indicator.

Achieving this goal is explained by the dependence of the frequency of the oscillations generated by the high-frequency generator on the inductance of the coil of the oscillating circuit wound on a ferromagnetic ring from the studied ferromagnet, and the inductance is directly proportional to the measured value of the magnetic susceptibility χ (Н).

The invention is clear from the presented figure.

The device contains:

1 - ferromagnetic ring from the studied ferromagnet,

2 - electromagnet (with north N and south S poles),

3 - winding of an electromagnet,

4 - adjustable direct current source,

5 - film Hall sensor,

6 - coil wound on a ferromagnetic ring 1,

7 - capacitor of the oscillatory circuit,

8 - high-frequency generator,

9 - frequency meter,

10 - meter of magnetic field strength,

11 - decisive processor with an indicator.

Consider the action of the claimed device.

On the ferromagnetic ring 1 from the studied ferromagnet, an inductance coil 6 of the oscillating circuit is made with a capacitor 7 connected in parallel to it and included in the high-frequency generator 8, the oscillation frequency f of which is determined by the formula f = 1 / 2π (LC) ^1/2 , where L is the inductance the coil 6 of the oscillatory circuit, C is the capacitance of the capacitor 7. The value of the inductance of the coil 6 wound on the ferromagnetic ring 1 is known to be determined by the formula L = [χ (H) +1] * L _O , where L _O is the inductance of this coil of the same geometry and number of turns, n without ferromagnetic core, i.e. at χ → 0. The value χ (H) + 1 = µ is the relative magnetic permeability of the ferromagnetic medium of the inductor 6. Consequently, the frequency of the oscillations f excited in the high-frequency generator 8 is inversely proportional to the square root of the magnetic susceptibility χ (H), i.e., f ~ 1 / [χ (H) +1] ^1/2 or, equivalently, χ (H) = (1 / 4π ² f ² L _O C) -1 is a function of f ^-2 .

The ferromagnetic ring 1 with coil 6 is completely placed in the magnetic gap of the electromagnet 2 with its magnetization winding 3, which is connected to an adjustable constant current source 4, and the latter allows you to smoothly change the magnetic field H in the magnetic gap of the electromagnet (this field is indicated by arrows in the figure), acting on the value of the magnetic susceptibility of the ferromagnet of ring 1 in the range 0≤H <H _MAX , where the value of H _MAX >> H _HAC . It is assumed that the range H _US ≤H≤H _MAX is known to work in paraprocess χ (H) * H = const .

The magnetization curve is calculated from the measured values of the frequency f in the frequency meter 9 and the magnetic field strength H in the meter 10 connected to the film Hall sensor 5 (the sensor excitation circuit is not shown in the figure) supplied to the first and second information inputs of the decoding processor with an indicator 11 J (H) = µ _O χ (H) · N or the magnetic susceptibility curve χ (H) of the studied ferromagnet — the dependence of its magnetic susceptibility on the magnitude of the constant magnetic field acting in it. These data are accumulated in the storage device and reproduced on the indicator in the form of a corresponding curve, called the Stoletov curve.

Literature

1. Preobrazhensky A.A., Bishard E.G. Magnetic materials and elements, 3rd ed., M., 1986.

2. Vonsovsky S.V. Magnetism, M., 1971.

3. Landau L.D., Lifshits E.M. Electrodynamics of continuous media. 2 ed., M., 1982.

Claims (1)

A device for measuring the magnetization curve of a ferromagnet, containing a ferromagnetic ring from the studied ferromagnet, placed between the poles of an electromagnet connected to an adjustable constant current source, an oscillating circuit coil made on a ferromagnetic ring and connected to a high-frequency generator, a film Hall sensor placed in the magnetic gap of the electromagnet, as well as a decisive processor with an indicator, characterized in that the high-frequency generator is connected to a frequency meter, The Hall sensor is connected to the input of the magnetic field strength meter, and the outputs of the frequency meter and magnetic field meter are connected respectively to the first and second information inputs of the deciding processor with an indicator.