SU705396A1 - Device for determining magnetic properties of specimens of magnetically soft materials - Google Patents

Description

(54) DEVICE FOR DETERMINATION OF MAGNETIC PROPERTIES OF SAMPLES OF MAGNETIC SOFT MATERIALS

The invention relates to a measurement technique and can be applied to determine magnetic

properties of ferromagnet materials and registration with the help of a recorder of periodic high-frequency signals, obtained by reversing samples of such materials,

Strobe devices for studying the magnetic properties of samples of ferromagnetic materials are known. Such devices contain sources of magnetizing currents, stroboscopic mixers, integrators, a strobe pulse shift system. In such devices, a signal proportional to the rate of change of magnetic induction is obtained on the secondary measuring winding of the sample under test, and a signal proportional to the rate of change of the intensity of the magnetic field is received on the secondary winding of the mutual coil. of the primary circuit whose winding is connected in series with the magnetizing winding of sample 1

However, the accuracy of measurements of the properties of magnetic materials using

such devices is insufficient. This happens due to the fact that the gating step remains constant at any speed, the change of the studied signals. In this case, there is a partial loss of information, which reduces the accuracy of measurements.

The closest in technical essence is a device that contains a series-connected master oscillator, a generator of torsional magnetization current, a magnetizing winding of the test sample and a resistor connected in series with the sample measurement winding, the first stroboscopic mixer. The first filter amplifier and the first integrator connected to the resistor are sequentially connected to the second stroboscopic mixer and the second filter amplifier connected in series Fast sawtooth generator, reference element and gate driver, output connected to the second mixer inputs, slow saw saw voltage, sequentially connected rectifier, second integrator

. A subtractor unit, with the rectifier input p1e11 connected to the output of the first filter of the amplifier, the output of the slow sawtooth generator to the second input of the reading unit, and the output of the last to the second input of the reference element 12 This device reduces the pulse shift and increases the recording time parts of the signals, where the rate of change of the magnetic flux turns out to be quite large, however, it is possible that the magnitude of the magnetic flux varies slowly as compared with the change in the strength of the magnetic field (for example, This test is performed when testing samples of materials with a given impulse intensity magnet nggo field). Since the correction of the strobe pulse voltage and the time of the pierHCTpau of signals is carried out only depending on the rate of change of the magnetic flux, there will be an error. due to the loss of information in the channel measuring the intensity of the magnetic field. The aim of the invention is to improve the accuracy of measuring the properties of magnetic materials, -.v -;:;. ".:;, :: -, .... To do this, the device for determining the magnetic properties of samples of magnetic materials containing series-connected real-time generator, magnetizing current generator, magnetized) winding and Primary winding of the coil: nominal inductance, connected in series measuring winding of the sample, the first stroboscopic mixer, the first filter amplifier and the first integrator connected to the secondary circuit The mutual inductance of the second strobe mixer, the second filter amplifier and the second integrator connected in series a fast sawtooth generator, voltage, the reference element and a pulse generator with output connected to the second inputs of both stroboscopic mixers, a slow sawtooth generator connected to one from the inputs of the subtraction unit, to the second input of which the third integrator is connected, and to the output - the second input of the comparison element, rectified Tel downstream connected to the output of the first filtrausilitel, two keys are introduced, the second rectifier coupled to the second filter-amplifier block Sryvygeky rectified voltage inputs Ko, torogo connected to the outputs of rectifiers and the outputs - to the inputs of the first cells. whose, the second inputs of which are connected to the outputs of rectifiers, and the outputs to the input of the third integrator.

Claims (2)

705396. FIG. I shows a structural electrical circuit of the device; FIG. 2 - time diagrams of the device operation. The device contains a master oscillator 1, a generator 2 ng1 magnetising current pulses, a magnetizing winding 3 of the test sample, a test sample 4, a measuring winding 5 of the test sample, the primary winding 6 of the mutual inductance coil 7, the secondary winding of the mutual inductance coil 7, stroboscopic mixers 8, 9 channels and magnetic field strength, respectively, filter amplifier 10 induction measurement channel, filter amplifier 11 channels magnetic intensity measurement Peel, integrator 1 2 induction measurement channels, integrator 13 channels for measuring the magnetic field strength, rectifiers. 14, 15 channels for measuring the induction and intensity of the magitite field, respectively, the comparison unit 16 rectified voltages, the keys 17, 18 channels, measuring the induction and magnetic field strength, respectively, the driver 19 strobe pulses, the comparison element 20, the fast sawtooth generator 21, a slow sawtooth generator 22, a subtraction unit 23, an integrator 24 of a circuit. The device operates as follows: Signal1 "1st master oscillator 1 starts generator 2 of magnetizing current pulses fed into magnetizing winding 3, the test-. The sample 4 is remagnetized and an electromotive force (EMF) is induced in the measuring winding 5, proportional to the rate of change of the magnetic flux (induction) in the sample. This signal enters the mixer 8, the mixer 9 receives the electromotive force, nfionoprotsionno the speed of change of the magnetic field, found in the secondary winding 7 of the mutual inductance coil during the flow of magnetizing current through the primary winding 6, sequentially connected to the magnetizing winding of the test sample. The master oscillator 21 also starts up from master oscillator 1. The voltage of the fast enters one of the inputs of the reference element 20, the second input of which receives the voltage of the slow sweep. At the equal moments of the voltage of the fast sawtooth and slow sweep, the pulses shifted in time relative to the pulses of the effective generator appear at the output of the comparison element 20. The time shift of the received pulses will be proportional to the instantaneous values of the compared stresses, since the rate of change of the 6th rapid sawtooth voltage is constant, then the change in the temporal shift of the pulses will be determined by the instantaneous1 voltage of the slow sweep. 20 pulses arrive at the strobe pulse former. The latter enter the mixers 8 and 9.. As a result of the interaction of strobe pulses and -signals, coming from the test sample, mixers 8, 9 produce a signal, which then feeds into filter amplifiers 10 and 11. At the output of filter amplifier 1, a time-transformed signal proportional to the rate of change of magnetic flux ( induction) duB / dCTj and on the output of the filter amplifier 11 is a signal proportional to the rate of change of the magnetic field strength -. du, / d-yy. Next, the signal from the output of the filter amplifier 10 enters the integrator 12, at the output of which nojiy a voltage proportional to the magnetic flux (induction) from the output of the filter amplifier 11 is fed to the signal: the interrator 13, the output of which receives a voltage proportional to the magnetic field - Its. From the output of the filter amplifier 10, a voltage proportional to the rate of change of the magnetic flux (induction) in the sample (Fig. 2a) enters the rectifier 14, where a signal is taken that is proportional to the INPUT module (Fig. 26), Voltage from the output of the filtering amplifier 11 enters rectifier 15, where the signal proportional to the input module is also selected. Then, the voltage "and from the outputs of the rectifiers 14, 15 are fed to the inputs of the comparator of rectified voltages 16. In this block the voltage moduli are proportional, proportional to the rate of change of the magnetic flux and the rate of change to the field of the magnetic field, and generating the key management signals 17, 18; Moreover, the control signal opens the key, to the input of which a higher voltage is applied. In accordance with this, the signal to the input of the integrator 24 will go through the key 17 if a large voltage from the rectifier 14 arrives at its input. If a larger signal is received from the rectifiers 15 to the input of the key 18, then the output of the latter will go to the integrator 24, The integrated voltage (Fig. 2c) from the output of the integrator 24 goes to one of the inputs of the subtraction unit 23, to the second input of which a slow sawtooth voltage is received from the generator 22 (FIG. 2d). From the block 23, where the incoming subtraction stresses, stresses Slow Sweep Up (Fig. 2d) is fed to one of the inputs of the reference element 20. At the output of subtractor 23, the slow sweep voltage is reduced by an amount proportional to the change in magnetic flux (induction) or the magnetic field strength in the sample, at times these changes occur. This leads to a decrease in the time shift of the strobe pulses and an increase in the time of registration of a part of the signals, where the rate of change of the magnetic flux (induction) or the intensity of the magnetic field in the sample is sufficiently large (Fig. 2d). Thus, the proposed device makes it possible to reduce the error in measuring and recording sigCals obtained by reversing the magnetic samples of magnetic materials. A decrease in the error is provided by a decrease in the gating step and an increase in the registration time of the part of the signals where their rate of change is quite high ;. This allows the Application to register the converted signals with precision instruments, but inertial instruments. Apparatus of the Invention A device for determining the magnetic properties of samples of magnetically soft materials, containing a series connected generator: a generator, a magnetizing current generator, a magnetizing winding and a primary winding of a mutual inductance coil, a series connected measuring winding, the first stroboscopic mixer, the first filter amplifier, and the first integrator, connected to the secondary winding of the coil, mutual inductance sequentially connected. The second stroboscopic mixer, the second filter amplifier, and the second integrator, are connected in series to a fast sawtooth generator, comparer and strobe pulse generator, output connected to the second inputs of both stroboscopic mixers, a slow sawtooth generator / connected to ONE of the subtraction unit inputs , to the second input of which the third integrator is connected, and to the output of the second input of the comparison element, a rectifier connected to the output of the first filter amplifier, r Ji ichayuschiys theme that in order to improve the measurement accuracy in. He additionally introduced two keys, the second wap1 speaker, connected to the second filter amplifier, block compare rectified voltages whose inputs are connected to the outputs rectifiers, and the outputs - to the first inputs of keys, the second inputs of which are connected to the outputs of the rectifiers, and outputs - to the input of the third integrator. Sources of information taken into account during the examination 1. E Chernyshev, T, et al. Magnetic changes, M ,, Standards Committee, 1969, p. 69, 2. Application 2454057/21, according to which the decision to issue an author's certificate was made. mich srt / i .-., / ,, 4f xy