SU1228058A1 - Device for measuring magnetic permeability of ferromagnetic materials - Google Patents

Abstract

The invention relates to a technique for measuring magnetic parameters and can be used to determine the characteristics of ferromagnetic cores. The purpose of the invention is to improve the accuracy of measuring the frequency dependence of the components of the complex magnetic permeability. The device contains a generator 1, a multiplier of 2 voltages, an amplifier 3, a comparator 4, a source 5 of a reference voltage, a remagnetizing winding 6, a measuring winding 7, an integrator 8, a resistor 9, synchronous detectors 10 and 11, a phase shifter 12, a two-shouldered oscilloscope 13 of a recording device and a 14 level converter. Introduction of a generator 1, a voltage multiplier 2, an amplifier 3, a comparator 4, a source 5 of the reference voltage, a level converter 14 and a resistor 9 will ensure the continuity of the permeability measurement process. During the removal of characteristics, the sample does not have time to reach high temperatures. 1 il. (About 1C S 00 C71 00

Description

The invention relates to a technique for measuring magnetic parameters and can be used to determine the characteristics of ferromagnetic cores.

The purpose of the invention is to improve the accuracy of measurement of the frequency dependence of the components of the complex magnetic permeability by continuous measurement of the magnetic permeability. When characteristics are removed, the sample does not have time to reach high temperatures.

The drawing shows a block diagram of the device.

The device consists of a generator 1, a multiplier of 2 voltages, an amplifier 3 and a comparator 4, a source 5 of a reference voltage, a remagnetization winding 6, a measuring winding 7, an integrator 8, a resistor 9, a synchronous detector 10 and 11, a phase shifter 12, a two-sided oscilloscope 13, recording device and converter 14 level. The output of the generator 1 is connected to the voltage multiplier 2, the input is connected to the output of the level converter 14 and the synchronization input of the recording oscilloscope 13. The output of the oscilloscope sweep 13 and the input of the level converter 14 are connected to the input of the voltage multiplier 2. The output of multiplier 2 is connected via amplifier 3 to remagnetization winding 6, phase shifter 12 and control input of the first synchronous detector 11, the second output of magnetic switching winding b is connected via a resistor 9 to a common point and the second input of comparator 4, the first input of comparator 4 is connected to source 5 of reference voltage, and the output of the comparator 4 is with the control input of the amplifier, the output of the phase shifter 12 is connected to the control input of the second synchronous detector 10, the measuring winding 7 is connected to a common point by one output and the other, via the integrator 8, with the signal inputs of two synchronous detectors 10, 11, the outputs of synchronous detectors are connected with two inputs of a recording device, a dual-beam oscilloscope 13.

The device works as follows.

The sawtooth voltage from the output of the oscilloscope sweep generator 13 is fed to the input of the level converter 14, in which the reference frequency and the frequency span of the signal frequency are set. The converted control signal is fed to the external synchronization input of the oscilloscope 13 and to the input of the controlled harmonic oscillator 1. As a result of this effect, the frequency-sinusoidal signal at the output of it varies linearly-synchronously depending on the instantaneous value of the control sawtooth voltage. The signal from the output of the generator 1 is fed to one of the inputs of the multiplier 2, and to the other its input is a control sawtooth voltage. After multiplying the amplitude, the harmonic signal varies linearly with frequency and is fed to the input of amplifier 3 loaded on the remagnetization winding 6. Comparator 4 compares the value of the voltage drop across the measuring resistor 9 with the value of the voltage of the reference source 5, which sets the required value of the remagnetization current, and, consequently, the magnetic field in the winding b, and affects the control input of the amplifier 3. As a result, any deviation of the bias current from the specified value of the correction Rowan by varying the amplifier gain. The complex resistance of the sample under study is found from the expression:

i2 | V + (/ (oL) V (1)

where R is the active resistance of the measurement winding; / wL - reactance.

The inductance magnitude L is a function of the sample cross section, the number of turns of the magnetic reversal winding, and the complex magnetic permeability.

c c -;, (2)

where | a ,, n, is the real and imaginary part of the complex magnetic permeability.

Magnetic losses are determined by the relation:

thirty

.b.

(3)

Therefore, the frequency dependence of L is determined by the frequency dependence of | A .. The voltage at the output of the measuring winding 7

proportional to the derivative of magnetic induction, after integration, it enters the inputs of synchronous detectors 10 and 11. The reference voltage at the inputs of the detectors is shifted by 90 ° by the phase shifter 12, as a result, the outputs of the detectors will be signals proportional to c and c, which are fed to the inputs of a two-sided oscilloscope 13 .

Claims (1)

Invention Formula A device for measuring the magnetic permeability of ferromagnetic materials, containing a reversing magnetizing winding, measuring winding, one output of which is connected to the common bus and the other through the integrator, to two synchronous detectors, the control input of one synchronous detector is connected directly to the reversal winding, and the other through the phase shifter, the outputs of the synchronous detectors are connected to a recording instrument, in order to improve the accuracy of measurement, sequentially connected are inserted into it generator, voltage multiplier and amplifier1228058 34 A comparator, a voltage reference voltage source, a transformed voltage output, a level converter and a level converter are connected to the control input by a resistor, the output of the amplifier of the connecting registering device and the input to the single output terminal of the remagnetization, the reference source the voltage of the winding, the second output of which is connected via a resistive key to the first input of the comparator, the second is connected to the common bus, the output of which is connected to the register of the remagnetizing device is connected to the input of the transducer and the output of the comparator of the level generator and the second input is perg-connected to the control input of the amplifier.