SU1205086A1 - Meter reversal of magnetization loss - Google Patents

Description

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This invention relates to measurable. gel technique and can be used to determine the magnetic reversal loss in testing of ferromagnetic samples.

The purpose of the invention is to improve the accuracy of measurements of magnetization reversal losses,

FIG. 1 shows a block diagram of the magnetization loss reversal} in FIG. 2 - time diagram of his work; FIG. 3 shows a hysteresis loop, explaining the principle of operation of the device.

The magnetisation loss measurement meter contains a magnetization unit 1 consisting of a magnetizing current generator 2, the output of which is connected to a magnetizing winding

3 applied to the test sample 4; The second end of the magnetizing winding through the exemplary resistance 5 is grounded. The composition of the loss of magnetization losses

The measuring winding 6 is also applied to the test sample.

4, one end of which is grounded and the other end connected to the input of the voltage / frequency converter 7. The output of the voltage-to-frequency converter 7 is connected to the counting input of a frequency divider 8 with a variable division factor, made, for example, on K155IE8 chips), the control input of which is connected

with the output of the analog-digital converter 9, and the output is connected to the counting input of the reversing counter 14, the output of which is the output of the device. The output of magnetization unit 1 is connected to the inputs of the analog-digital converter. 9 and the second discriminator 10 zero level. The outputs of the discriminator 10 and 11 of the zero level are connected via an ogical circuit OR 12 to the input of the character trigger 13, the output of which is connected to the control input of the reversible counter 14 "The output of the control unit 15 is connected to the start input of the magnetizing current generator 2 and 13 reversible counter 14. Block 15 control is made, for example, on the basis of a pulse generator type G5-15. The device works as follows.

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The control unit 15 sets the reversible counter 14 to O, and the trigger 13 signs to the state, the reversible counter 14 is transferred to the subtraction mode, and starts the magnetizing current generator 2. The latter creates a current in the magnetizing winding 3, under the action of which the magnetization reversal of sample 4 and in the measuring winding 6 induces an emf e proportional to. the rate of change of induction in test sample 4

15

e -Sh3 „

Jb dt

where W is the number of turns in the measuring winding;

S0 is the cross section of the sample; B - induction in the test sample.

The frequency of the pulses f at the output of the converter 7 voltage to frequency is proportional to the absolute value of the emf e

f,

k. w -S ,,

li it

where k, is the voltage-to-frequency conversion factor.

The N code at the output of the analog-to-digital converter 9 is proportional to the absolute value of the intensity H in the test sample 4

N C (N

where k is the conversion factor of the analog-to-digital converter 9.

The frequency of the pulses, at the output of the divider 8 frequency with a variable division factor is equal to the product of the input frequency f, by the value of the current code N, coming from the output of the acetal-digital converter 9

fj f, N .lHl

dB

dt

50

Jb

Jt

where t.

Consider the case of a magnetization reversal of the sample according to the law

FIG. 2. Due to the fact that the reversible counter is in the subtraction mode, with the remagnetization from

points (B) (fig. 3) to point (Oj-Bf,), i.e. in the time interval tp-t, (Fig. 2), the code in the reversible counter 14

i, i, -t Ut .jf

4I OL J

 In-r

iHlljBl

and proportional to the area S ((FIG. 3). When the magnetic reversal is from the point (0; -Bj,) to the point (B), i.e., in the time interval t, - tj (Fig. 2), the intensity H in the subject the sample changes sign, and the zero-level discriminator 10 is triggered.The signal from its output through the logic circuit OR 12 is fed to the input of trigger 13, which changes its state to the opposite and thereby transforms the reversible counter 14 into the summation mode. N

1 in „,

add the code, | H || db i. -g

Thus, with the arrival at point (H, B) in the reversible counter 14, the code N - -N, + Nj is formed, proportional to the area

-S, + S,

+ S

3

With further magnetization reversal, the EMF in the measuring winding 6 changes its sign, the discriminator 11 of the zero level is triggered, the signal ic of its output through the logic circuit 1205086

A mu or 12 overturns the trigger 13 characters, as a result of which the reversible counter 14 is switched to the subtraction mode. With coming to a point (Oj

BP) i.e. at time t, code 14 is generated in counter 14

C 8

VN3-Jiz bN, - 3JlH | ldB |, ti B „,

agricultural area (5 + S ,,

In this MO8z) - BZ -S,

+ S,

The intensity H in the test sample changes its sign, which triggers the zero-level discriminator 10, and the reversible counter 14 is again switched to the summation mode.

To the contents of the reversible counter 14 when moving from a point (0; B) to a point (-H, - -B), i.e. in the interval, the code is proportional to the area S + S,. Thus, at the end of the magnetization reversal period, the code is stored in the reversible counter 14

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, c3bN, u, j iH | ia-B |,

Squares (-S,

S

S,) +

H

those. full

the area of the hysteresis loop, and, therefore, proportional to the magnitude of the losses in the magnetization reversal of this sample.

Claims (1)

REMagnetization LOSS MEASURER, comprising a magnetization block, comprising a magnetizing current generator connected in series, a magnetizing winding and a reference resistor, a measuring winding connected to the input of the voltage to frequency converter and the input of the zero level discriminator, the sign trigger, the output of which is connected to the control signal and a control unit, the output of which is connected to the input of the magnetizing current generator, with the installation inputs of the sign trigger and reverse counter, characterized in that, in order to improve the accuracy of measurements, a frequency divider with a variable division coefficient, a second zero-level discriminator, an analog-to-digital converter and an OR circuit are introduced into it, the counting input of the frequency divider is connected to the output of the voltage-to-frequency converter controlling the input is connected to the output of the analog-to-digital converter, and the output with the counting input of the reverse counter, the input of the second zero-level discriminator is connected to the output of the magnetization unit and to the analog-to-digital input a converter, wherein the outputs of the two discriminators zero through OR logic circuit connected to the counting input of the sign flip-flop.