SU1167552A1 - Device for determining magnetic properties of soft magnetic materials - Google Patents

Abstract

DEVICE FOR DETERMINING THE MAGNETIC PROPERTIES OF SOFT MAGNETIC MATERIALS, comprising a generator, a power amplifier, permeameter with two yokes, the magnetizing and measuring windings, ammeter, voltmeter, wattmeter, wherein the measuring coil permeameter connected voltmeter and circuit voltage wattmeter and a first terminal of the field winding - The first output of a mop amplifier, the input of which is connected to a generator, is characterized in that, in order to increase the measurement accuracy, a two-choke choke and a magnetizer are introduced into it Chiva winding two measuring AC transformer, the first one. which contains two, and the second - three; Winding, two resistors and a switch, and inserts made of magnetic material are placed in the gaps of the throttle magnetic core and in the magnetic core of the permeameter; , the first output of the throttle magnetizing winding - to the first output of the serially connected second-winding measuring transformers, and the second output - to the first output of the force A power supply, the second winding of the first measuring transformer is closed to the first resistor, the second terminals of the first and second windings (L of the second measuring transformer are connected to the second output of the power amplifier, the ammeter and the current circuit of the second meter are connected to the third winding of the second measuring transformer the first output of the power amplifier, the second terminal -vj with a movable contact switch, SP C To the fixed contacts which are respectively connected to the V rum conclusion permeameter magnetizing winding and the first terminal of the magnetizing winding of the choke.

Description

} 1 The invention relates to a measuring technique and can be used to determine the specific magnetic. losses, magnetic induction and magnetic field strength on samples of magnetically soft materials in the form of individual strips, bags and sheets when they are re-magnetized by varying current. The purpose of the invention is to improve the accuracy of measurements by extracting the signal by means of droplets and transformers, caused only by reversal of the sample. ; FIG. 1 is a schematic diagram of the device; in fig. 2 magnetic circuit permeametra and droselsel. The device contains a generator 1, power amplifier 2, which creates the required magnetization mode. Permeameter 3 has magnetizing 4 and measuring 5 windings. A voltmeter 6 and a voltage circuit of a wattmeter 7 are connected to the latter. Consistently with the magnetizing winding 4 of the permeameter 3, the first winding 8 of the first measuring current transformer 9 is connected, as well as the first winding 10 of the second measuring current transformer 11. The magnetizing winding 12 of the 13th connectors 13 is connected in series with the second a resistor 14 shunting the second winding 15 of the first measuring transformer 9, and with the second winding 16 of the second measuring transformer 11. The third winding 17 of the second measuring transformer Ormator 11 is connected to an ammeter 18 and a current circuit of a wattmeter 7. Permeameter 3 (Fig. 2a) has two roma 19 and 20, between which test sample 21 is placed, covered by windings: magnetizing 4 and measuring 5. Choke 13 (Fig. 26) has two roma 22 and 23. In the gaps between the roma of the throttles are placed inserts 24 and 25 of a material whose properties are close to the characteristics of the test sample. On the frames 22 and 23 sections 26 and 27 are placed, which, being connected in series according to, form the winding 12 (Fig. 1). The numbers of turns in sections 26 and 27, as well as in winding 4, are the same, which ensures equal magnetic fluxes in the throttles 13 and permeameter 3. In addition, the numbers Vit2 kbv in the windings 10 and 16 are equal to these conditions according to the ammeter and the current circuit of the wattmeter, proportional to the difference of the magnetizing currents flowing through the windings 4 and 12, which eliminates the influence of the magnetisation of the rem and the transition of the magnetic flux from the sample into the frame and back to the results of measuring magnetic quantities. Resistor 28 and switch 29 allow to equalize the losses in the throttle and permeameter circuits, even in the absence of a strict rem identity. The use of drossel with inserts in conjunction with the second instrument transformer allows the signal to be isolated, due only to the remagnetization of the test specimen. The first measuring transformer with a resistor ensures the introduction of a correction signal into the Drossel magnetizing circuit, creating the same conditions for the remagnetization of the latter as in the permeameter (for example, a sinusoidal change in the magnetic flux time). This makes it possible to eliminate the error in measuring magnetic quantities due to the nonidentity of the magnetism of the throttles and the permeameter. The device works as follows. The frequency and shape of the magnetic induction curve are set by generator 1. Power amplifier 2 feeds the magnetizing circuit of sample 21 placed in permeamet 3. The magnetizing current flows through winding 4, and the voltage on measuring winding 5 is measured with a voltmeter 6 and supplied to the wattmeter voltage circuit 7. The magnetizing current also flows through the winding 8 of the first measuring transformer 9 and the winding 10 of the second measuring transformer 11. The alternating current, the magnetized choke 13, flows through a two-section winding .12, the second resistor 14, winding 15 of the first measuring transformer 9 and winding 16 of the second measuring transformer 11. The voltage drop across the resistor 14 depends on the magnetizing current of the sample 21. If the resistance

R of resistor 14 is determined by the formula:

Rz

(one)

active resistance on the 1C magnetization chain of the sample

Ohm;

the number of turns in the windings 15

W, W and 8, respectively, the shape of the magnetic flux curves, in the droselle and permeameter, will be the same because the current in the winding 17 of the second instrument transformer 11 is determined by the difference between the magnetizing currents of the permeameter 3 and the droplet 13, the ammeter 18 the magnetic field in sample 21, while the wattmeter is a specific magnetic loss, provided that the permeameter and the droselt have the same magnetic losses. If these taps are not identical, then to equalize the losses, one of the windings (A or 12) is bridged by a resistor 28, which is connected to the windings by a switch 29 (Fig. 1).

The amplitude of the magnetic induction B in sample 21 is calculated by the formula

and.

(2)

Pw f5WH

, dd J „is the average value of voltage, changed by voltmeter 6, RJ; f - frequency of magnetization reversal

sample, Hz; S is the cross-sectional area

sample,

W is the number of turns in the winding 5. The intensity of the magnetic field H in sample 21 is equal to

%

(3)

N wjfcp

where i is the current strength measured by ammeter 18, A;

1 — average length of the magnetic field line in the sample, m; W W - the number of turns in the windings 17 and 10, respectively; W is the number of turns in the winding 4. The specific magnetic losses are equal

.I,

Claims (1)

'DEVICE FOR DETERMINING THE MAGNETIC PROPERTIES OF MAGNETIC SOFT MATERIALS, containing a generator, a power amplifier, a permeamer with two yokes, a magnetizing and measuring windings, an ammeter, a voltmeter, a wattmeter, and the voltmeter and voltmeter are connected to the permemeter by a first volt meter and a voltage meter the output of the magnetizing winding is the first output of the power amplifier, the input of which is connected to a generator, characterized in that, in order to increase the accuracy of measurements, a choke with two yokes and a magnet vayuschey winding two measuring AC transformer, the first one. which contains two, and the second - three windings, two resistors and a switch, and inserts of magnetic material are placed in the gaps of the inductor magnetic circuit and in the magnetic circuit of the permeameter, while the second output of the magnetizing winding of the permeameter is connected to the first output of the first windings of the measuring transformers connected in series, the first output the magnetizing winding of the inductor - to the first output • of the second windings of the measuring transformers connected in series, and the second output to the first output of the amplifier In fact, the second winding of the first measuring transformer is closed to the first resistor, the second terminals of the first and second windings of the second measuring transformer are connected to the second output of the power amplifier, the ammeter and the current circuit of the wattmeter are connected to the third winding of the second measuring transformer, the first terminal of the second resistor is connected to the first output of the power amplifier, the second terminal with a movable contact of the switch, the fixed contacts of which are respectively connected to the second terminal of the magnetizing permeameter conductive winding to the first terminal and magnetizing inductor winding.