SU676958A1 - Method of registering asymmetrical hysteresis cycles - Google Patents

Description

one

The invention relates to the field of magnetic measurements and can be used to construct automatic recorders of asymmetric hysteresis cycles when testing ferromagnetic materials in the modes of simultaneous exposure to constant and alternating magnetic fields.

There are known methods for registering asymmetric hysteresis cycles based on a combination of methods for testing ferromaterials in dynamic and static modes of magnetization reversal 1.

The variable component of the induction magnetic field is determined from the output of the inductive primary transducer (measuring winding of the sample). The constant component of the magnetic induction in an induction transducer, which has differentiating properties, is lost and is determined by an additional operation using a fluxmeter or a ballistic galvanometer on the EMF pulse at the output of the additional winding.

There is a known method for determining the dependence of the instantaneous values of induction and magnetic field strength, which consists in simultaneously magnetising a sample with constant and alternating magnetic fields, determining the integral function of the measuring winding signal, converting electrical signals proportional to the integral function

the measuring winding signal and the magnetic field strength, into a graphic representation of asymmetric hysteresis cycles, determining the constant component of the fluxmeter induction and shifting the image of the private cycle to the constant component of induction along the induction axis 2.

However, these methods do not allow automating the registration process; they are time consuming, associated with the use of a fluxmeter and the operator’s participation in combining the results of measuring the constant and variable components of the induction. In addition, the measurement process is accompanied by considerable misstatements in the graphic construction of private cycles, taking into account the constant component of induction, which are superimposed on the fluxmeter error of 8-10%.

The purpose of the invention is to improve the accuracy and automation of the registration process.

The goal is achieved by the fact that, according to the method based on simultaneous

Claims (2)

magnetizing the sample with constant and alternating magnetic fields, determining the integral function of the sample measuring winding signal and converting electrical signals proportional to the integral function of the measuring winding signal and the magnetic field strength, periodically changing the direction of the direct current creating a field into the graphical image of the asymmetric hysteresis cycles bias, on the opposite with a period multiple of the period of the alternating magnetic field. When ensuring the specified sequence of operations, the total intensity can be considered as a combination of two variable components // E // 1 -J-; BZ BI +52, where HI- and BI are the variable components of induction and intensity; // 2 and Woo-variable components characterizing a periodically inverted field. In this case, the output of an inductive primary converter having differentiating properties is an electrical signal of the measuring winding of the primary converter dB dBi dB2 I FH / Y # - // T and when integrating eBdt B, (t) + B, (t), i.e. When determining the integral function of the signal, information is kept about both the variable Bi (t) and the constant Bz (t} components. At the same time, the magnetic induction in the material during the change in direction (two sign changes) of the bias current does not contain a constant component, at the same time, the average for the half period bias current induction value corresponds to a constant component with a constant field bias in one direction. During the second half-period of the bias current, the magnetic state of the core varies along a path that is symmetrical about the origin of coordinates (in the plane B and I) along the auxiliary cycle. 1 shows a functional diagram of the device that implements the proposed method; FIG. Figure 2 shows the shape of the magnetizing signal Yaa, the trajectory of the change in the magnetic state of the material in coordinates B and H, the mode of induction change BS in the sample corresponding to this mode. The functional circuit consists of master oscillator 1, power amplifier 2. ferromagnetic core 3 (sample) with magnetizing and measuring windings, integrator frequency divider 5, reference resistor 6, biasing current source 7, switch 8 and registration unit 9. The signal determining the parameters of the alternating magnetic field from the master oscillator 1 through the power amplifier 2 is fed to the magnetizing winding of the sample 3. A signal from the bias current source 7 generating the bias field is fed to the same winding. Changing the direction of the bias current is carried out by the switch 8 with the frequency set by the frequency divider 5, the output of which is connected to the control input of the switch. The multiplicity of the period of change in the direction of the bias current and the alternating magnetizing current is ensured by the fact that divider 5 receives a signal from master oscillator 1. The signal from the measuring winding of sample 3 is transmitted through integrator 4 to the first input of detection unit 9. The second input of the registration unit receives a signal proportional to the voltage from the reference resistor 6. Periodically changing the direction of the bias current excludes from the registration process the operation of determining the constant component of the ballistic galvanometer and fluxmeter, and therefore, automation becomes possible, the efficiency is high, the accuracy is increased, simplification of the registration process of asymmetric hysteresis cycles. Claims The method of detecting asymmetric hysteresis cycles by simultaneously sample magnetization of a constant and alternating magnetic fields, determining the integral function of the sample measuring winding signal and converting electrical signals proportional to the integral function of the measuring winding signal and magnetic field strength, into a graphical representation of non-symmetrical hysteresis cycles This is due to the fact that, in order to improve the accuracy and automate the registration process, the period The change in the current density of the current created by the bias is reversed to the opposite of a period that is a multiple of the alternating magnetic field. Sources of information taken into account in the examination 1. Works VNIIM. Issue 29 (89), 1956, L.,. 109-116. 2. Kiefer I. I. Testing of ferromagnetic materials. M ,, “Energie, p. 285. uz.Z