SU905893A1 - Ferrometer - Google Patents

Description

(54) FERROMETER

The invention relates to magnetic measurements and can be used to determine the dynamic hysteresis curves of magnetic cores under conditions of periodic magnetization reversal, in particular when magnetized by a constant magnetic field.

It is known to use oscillographic devices for determining dynamic hysteresis curves that have a low accuracy of intent.

Closest to the invention is a ferrometer consisting of two transducers, a synchronous detector, a measuring device with a constant voltage component, the input of which is connected to one of the transducers through the detecting contacts of the synchronous detector, and. a series-connected synchronization voltage source, a phase regulator and a control rectangular voltage driver, the output of which is connected to the control input of a synchronous detector, the control driver

The rectangular voltage is made according to the Imidt trigger circuit tl.

However, the known ferrometer is not applicable for determining asymmetric dynamic hysteresis curves, since it operates according to the method of synchronous detection with a half-periodic cutoff duration and

4Q is therefore sensitive only to the odd harmonics of the input voltage forming the measuring transducer, and insensitive to the even harmonics of this voltage arising from the determination of asymmetrical dynamic hysteresis curves. It is advisable to combine the high accuracy of the ferromometer with the possibility of determining asymmetric dynamic hysteresis curves.

The purpose of the invention is to expand the functionality of the ferromometer.

This goal is achieved by the fact that

25 in a ferrometer containing two transducers, a synchronous detector, a voltage measuring unit, the input of which, through a synchronous detector, is connected to one of the transducers, the synchronization voltage source and phase regulator connected in series, and the control rectangular rectangle voltage, the first input of which is connected to the output of the phase regulator, and the output - with the control input of the synchronous detector, the second input of the driver of the control rectangular voltage voltage connected to the voltage source synchronization generator control rectangular voltage is formed as a latch with two separate inputs, and the synchronous detector is configured as an inverter.

FIG. 1 shows a ferrometer structural diagram; Fig. 2 shows graphs of voltage dependencies on time.

The ferrometer consists of two measuring transducers 1 and 2 (Fig. 1), a synchronous detector 3, a measuring unit 4 for a constant component voltage, the input of which is connected via a switch and a synchronous detector 3 to a measuring transducer 1 or 2, a synchronization voltage source 5 , phase regulator b, the input of which is connected to the source of synchronization voltage, and the driver 7 of the control rectangular voltage, made according to the trigger circuit with two separate inputs, the first input of which is connected to the output of the phases The second regulator is with the source 5 of the synchronization voltage.

Consider the work of the ferrometer.

The voltage, 2), generated by the synchronization voltage source 5, and the voltage io (Fig. 2), generated by the phase adjuster b, are converted by the former 7 into voltage pulses Uj (Fig. 2), the duration of which is controlled by the phase adjuster b . The voltage pulses U control the operation of the synchronous detector 3, with which the input voltage and (figure 2 formed by one of the measuring transducers 1 or 2, is converted into the detected voltage and (fig 2) applied to the input of the measurement unit 4 constant If the synchronous detector 3 is made according to the inverter circuit, the inverted voltage U j is formed instead of the detected voltage. By connecting alternately to the output of the inductor detector 3, the measuring converters 1 and 2 measure instantaneous values of the field of magnetic field and magnetic induction, i.e., coordinates of one point of determined dynamic hysteresis curve. Repeat changes for different positions of phase regulator b, i.e. for different moments t of constant t (determined by points dynamic hysteresis curve.

The input voltage Ug, formed by one of the measuring transducers 1 or 2, is proportional to the time derivative t of the measured quantity X (magnetic field strength or magnetic induction) and is expressed by the formula

dx

and - to

(one)

dt

where K is the proportionality coefficient.

The constant component U of the detected voltage C, measured by block 4, is equal to the average value of this voltage for the period T

and -4; - S Udt, (2). 0 t-i

where are the moments corresponding to the leading and trailing edges of the detection. From formulas (1) and (2) follows

X (,)

(one)

Formula (3) is a calibration dependence for a given ferrometer. The constant component of the detected voltage is expressed by the formula.

-

u;

LtQ

Since X (t-,) X (m) (periodicity condition), it follows from formulas (1) and (4)

- T:

X (t

X (t5i)

(five)

2K

Formula (5) is a calibration dependence for a given ferrometer, if the synchronous detector 3 is made according to the inverter scheme. From the fact that the first part of formula (5) contains a numerical factor of 2, it follows that the execution of the synchronous detector 3 according to the inverter scheme leads to an increase in the sensitivity of the ferrometer twice. The value of X (ti2) in formulas (3) and (5) is the integration constant, from the value of which the measured value X (t) is measured. When measuring x, X (ti3) should be considered as 0. In contrast to the known

The ferrometer calibration dependences for this ferrometer are derived without imposing the condition of odd input voltages. This ensures the applicability of this ferrometer for measurement in the presence of both odd and even harmonics of the input voltages, i.e., for determining both symmetric and asymmetrical dynamic hysteresis curves, for example, in the construction of complex magnetization reversal, in particular, with constant magnetic bias by the magnetic field. The present ferrometer combines high measurement accuracy with the ability to determine asymmetric dynamic hystereic curves and provides the basis for the development of universal ferrometers suitable for determining both symmetrical and asymmetric dynamic hysteresis curves for the practice of effective quality control of magnetic cores. A ferrometer can be used as a model for certifying standard samples of asymmetrical dynamic hysteresis curves of magnetic cores in the system for metrological support of working measurement tools, in addition, the ferrometer is applicable for the audio frequency range.

Claims (1)

1. Chechurina E.N. Phase sensitive voltmeter for determining ac hysteresis curves. Measuring equipment, 1962 ,. 6, s. 45 - 47 (prototype). Xj GH, 2