SU1404996A1 - Device for checking parameters of magnetic cores - Google Patents

Abstract

The invention relates to magnetic measurements # 1. A device for monitoring parameters of magnetic cores (MFs) with a non-magnetic gap contains a magnetisation current generator 1, a magnetizing winding 2, alternating and reference resistors 3 and 4, respectively, a rectifier amplifier 5, subtracting blocks 6 , 7, registration units 8, 9, level setting unit 11, analog switch 12, scaling amplifier 10, unit. 13 controls The device allows measurements without the use of reference MPs, which eliminates the error caused by the non-identity of the materials of the reference and controlled MPs. 1 il.

Description

(L

with a

The invention relates to magnetic measurements and is intended to monitor the parameters of magnetic cores with a non-magnetic gap.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows a functional block diagram of the device.

The device contains series-connected alternating current generator 1, magnetizing winding 2 5 alternating 3 and exemplary 4 resistors, to the common point of which the input of amplifier 5 is connected, the output of which is connected to the first inputs of the first 6 and second 7 subtractive blocks , the outputs of which are connected to the inputs of the first 8 and second 9 registration units, respectively, and the second inputs, respectively, directly and through a scaling amplifier 10 are connected to the output of the level setting unit 11. The input of the block 11 is connected via an analog switch 12 to the output of the first subtractive block 6. The control inputs of the analog switch 12 and the generator 1 are connected to the corresponding outputs of the control block 13. The measuring coil 14 is connected to a magnetic flux meter 15.

The device works as follows.

The signal of the control unit 13 at the output of the generator 1 establishes a magnetizing current with a frequency f, and at the same time closes the switch 12. At the same time, the current of the generator 1 flowing through the winding 2j causes a magnetic reversal of the magnetic core. The resistance of the resistor 3 is set according to the indications of the meter 15 so as to provide a predetermined magnetic flux g in the test magnetic circuit. A sample resistor is voltage proportional to the magnetizing force F, (), where RM is the magnetic resistance of the ferromagnetic part of the magnetic circuit; R mag

nitmatic resistance of a nonmagnetic gap.

Amplifier rectifier 5 converts an alternating voltage into a constant voltage level 5 proportional to the amplitude B ,,. The difference signal of the subtracting unit 6 acts on the input of the unit 11 through the open key 12, as a result of which the output of the unit 11 is set to a voltage equal to

5 0 5 About

Q

five

0

And m- (p (p-1) to the voltage at the output of the amplifier — vypir 5 m.

Then unit 13 switches the frequency of generator 1 and opens key 12. In this case, the new frequency fj of generator 1 is selected from the condition that the magnetic permeability of the magnetic core material decreases by a factor of m compared with the differential permeability at frequency f, for a given amplitude of the flux Φ. . The voltage established at the output of the block 9 in the first cycle of operation of the control unit 13 is stored in the second cycle. By changing the resistance of the resistor 3, a predetermined amplitude of the magnetic flux is established, and a constant voltage proportional to the new value of the magnetomotive force F () is formed at the output of the amplifier-voltator. Amplifier transmit power factor 10 n

-I

is set to m. As a result, in blocks 8 and 9, signals are recorded in the second measurement cycle,

proportional respectively jEilEi- (n-1)

Thus, the proposed device makes it possible to produce the co-role of the parameters of the magnetic cores with non-magnetic gaps without using reference magnetic circuits, which eliminates the error caused by nonidentity of the materials of the reference and controlled magnetic circuits.

Claims (1)

Invention Formula A device for monitoring the parameters of the magnetic cores, containing a series-connected magnetising current generator, a magnetizing winding, a variable resistor and an exemplary resistor, a rectifier amplifier whose input is connected to a common point of the variable and reference resistors, and the output to the first input of the first subtractive unit whose output is connected to the input of the first recording unit, a control unit and a measuring winding connected to the input of a magnetic flux meter, characterized in that, in order to fine measurement accuracy, it entered the second subtracting unit and the recording unit, setting unit 31404996 level, analog key and analog scale key connected to the output power amplifier, with the first input of the first subtraction of its block, and The second subtraction unit is connected, the output of the second subtraction unit is the output of the amplifier amplifier, is connected to the input of the second unit, the register inputs of the first subtraction blocking, and the outputs of the control unit are connected to the control inputs through the scaling amplifier the second is connected to the output of the unit by a generator of alternating magnetisation level, the input of which is a through-current and an analog key.