SU1307411A2 - Device for measuring intensity of magnetic field - Google Patents

Abstract

The invention is in addition to auth. No. 785813 relates to magnetic measuring technology and can be used to measure the magnetic field strength on the surface of a ferromagnet when tested in alternating magnetic fields during testing, when developing production technology, as well as improving the designs of electrical machines. The aim of the invention is to expand the frequency range while maintaining high measurement accuracy. The device contains a magnetic core 1 with a coil 2, a resistor 3, a two-pole4 with negative resistance, a registering device 5. To achieve this goal, a coil 6 with an inductance proportional to the leakage inductance of coil 2, a resistor 7, a voltage divider on resistors 8 and 9, amplifier 10. 1 Il. with SS (L W) 145

Description

113

The invention relates to a magnetometer and is intended to measure the magnetic field strength on the surface of a ferromagnet when tested in alternating magnetic fields during acceptance tests, to develop a production technology, and to improve the designs of electrical machines.

The purpose of the invention is to expand the frequency range while maintaining high measurement accuracy.

The drawing shows the functional diagram of the device. -

. The device contains a magnetic conductor 1 with a coil 2, through a resistor 3 connected to a two-pole 4 with a negative resistance, a recording device 5, connected in series with coil 6 with an inductance proportional to the leakage inductance of coil 2 of the magnetic circuit 1, and a second resistor 7 in parallel with which a voltage divider comprising third 8 and fourth 9 resistors; and amplifier 10, the inputs of which are connected to coil 2 and the connection point of resistors 8 and 9.

The device works as follows.

When the sample is magnetized, a magnetic voltage is generated on its surface, id, equal to UM H.I,

where H is the average magnetic field strength; 1 - the distance between the poles

magnetic conductor.

Under the action of U in the magnetic core 1, a flow F is created, and on the coil 2 a voltage equal to

yf

- W AGB UT- and.- and, + and I

where li is the voltage drop on the battery

coil resistance 2;

and,. - voltage drop across the additional inductor coil 6;

 - voltage drop on the inductance of the scattering of coil 2;

UY is the voltage drop across the second resistor 7;

U | jj is the voltage drop at the output of amplifier 10;

and - voltage drop on the negative resistance R - two-port 4;

and is the voltage drop across the reference resistor 3. When equalities are fulfilled

Un + OUSE "

short-circuit mode is performed with compensation of the active resistance and inductance of the scattering of coil 2. Current i in coil 2 creates a magnetomotive force that is opposite to and, and since complete compensation of the voltage drops on the active resistance and inductance of the scattering of coil 2 occurs, that

and „-: i-w

i um.

w

n | w

Therefore, by registering it, the device 5 can measure the value proportional to the intensity of the magnetic field. By calibrating the instrument scale directly in units of magnetic field strength, the intensity is measured with high accuracy.

Compensation of the voltage drop on the inductance of the dissipation of the coil 2 is performed as follows.

An additional coil 6 with an inductance proportional to the LS inductance of coil 2 is introduced into the electric circuit of coil 2 for simplicity, we take them to be equal in size), and the second resistor 7. When flowing through the current circuit i on the additional coil 6 inductance there will be a voltage drop equal to The inductor is dissipated by Katotakak 2 and thus doubled. The input of the amplifier 10 is supplied with voltage from the inductor 6 and the second resistor 7 through a divider formed by the third 8 and fourth 9 resistors, with a division factor equal to the ratio of the additional inductance of the coil 6 to the sum of it and the dissipation inductance of coil 2 (in this case 1 : 2), and from its output it goes in antiphase to the second resistor 7. With a significant coefficient

313

transmitting the voltage amplifier 10 at the second 7 resistor compensates for the voltage drop across the inductor 6 and the leakage inductance of the coil 2, i.e. for device equipotent equality

i AM

W

Claims (1)

In this case, the current in the winding, regardless of the inductance of its dispersion and frequency, repeats the value U ,, and the recording device 5 conducts a direct reading in units of the magnetic field intensity with high accuracy. Invention Formula  A device for measuring the magnetic field intensity according to the ed. St. No. 785813, distinguished by so that, in order to expand the frequency range of the measurements, an additional efficiency coil and a second resistor were added to it, a voltage divider made in the form of serially connected third and fourth resistors, and an amplifier, the first input of which is connected to the first coils of the coil and inductors, the second input is with the voltage divider output, the first output of the amplifier is connected to the second output of the inductor, the first input of the voltage divider and the first output of the second resistor, Torah output amplifier - vshodom a second voltage divider, the second vshodom second resistor and to the input two-terminal negative resistance.