SU1368829A1 - Device for measuring residual magnetization of articles made of ferromagnetic materials - Google Patents

Abstract

The invention relates to a measurement technique and serves to improve the accuracy and speed of a device. The device contains an alternating voltage generator 1, a reed switch 2, a magnetisation winding 7 and an indicator 8. Using a polarity converter 6 and an electronic attenuator 3 allows time and magnetic reed switch 2 to be combined. The use of the integrator 4 and the adder 5 allows the self-compensation principle providing high measurement accuracy, reaching 0.01-0.008 A / cm. The speed of the device increases 5-6 times and is determined mainly by the time constant of the integrator 4, was 0.06-0.1 s. 1 il. i (L

Description

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The invention relates to a measurement technique and can be used to control the residual magnetization of ferromagnetic parts for measuring the magnetic fields of solenoids, conductors with a current.

The aim of the invention is to improve the accuracy and speed of the device.

The drawing shows a diagram of the proposed device.

The device comprises an alternating voltage generator 1, a reed switch 2, an electronic attenuator 3, an integrator 4, an adder 5, a polarity converter 6, a bias winding 7, an indicator 8.

The output of the alternating voltage generator 1 is connected via the electronic attenuator 3 to the first input of the adder 5 and through the reed switch 2 and integrator 4 to the second input of the adder 5, while the output of the integrator 4 is connected through the polar converter 6 to the control input of the electronic attenuator 3, and the bias winding 7 and the indicator 8 are connected in series to the output of the adder 5.

The device works as follows.

The alternating voltage from the output of the generator 1 through the electronic attenuator 3 and the adder 5 is fed into the circuit from the series-connected windings 7 and the indicator 8. The amplitude of this voltage (field) is significantly higher (1.5-1.8 times) the value required for reliable operation of the reed switch. At the same time, the alternating voltage from the output of the generator 1 through the reed switch 2 is fed to the input of the integrator 4 in the form of modulated by different duration of different polarity pulses. In the absence of an external measured constant magnetic field, the duration of opposite-polarity pulses are equal, since only the symmetric alternating magnetic field of the bias winding acts on the reed switch. The integrator converts the width-modulated signal into a constant voltage of one or another sign depending on the magnitude and sign of the external magnetic (measurable) field imposed on the reed switch. This is a constant voltage from the output of the integrator 4 through the adder 5

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In antiphase to the bias winding, creating in it (the opposite field) a field equal in magnitude and opposite in sign measured.

At the same time, the output voltage of the integrator 4 through the polarity converter 6 acts on the electronic attenuator 3, reducing (in the limit to 40%) the value of the variable component in the bias winding. Thus, the reed switch is permanently in an alternating magnetic field, sufficient for its reliable closure (actuation), and at the same time in a constant field compensated by negative feedback.

The use of a polarity converter and an electronic attenuator makes it possible to combine measurement and magnetic preparation (demagnetization) of the reed switch in time, and the use of an integrator and adder can use the principle of self-compensation, which ensures high accuracy of measurements. Even with a moderate chain transfer ratio, the integrator –– adder of the order of 10 is the autocompensation accuracy per the order of Bbmje, than when manually setting the response threshold using a current regulator (0.01–0.008 A / cm compared to 0.1–0.15 A / cm in a known device).

The speed of the device is increased 5-6 times the constant of the integrator time and is 0.06-0.1 s instead of 0.4-0.6 s of the known. There is no need for preliminary magnetic preparation of the reed switch, since it is constantly located in the alternating magnetic field of the bias winding, decreasing in magnitude depending on the measured magnetic field, but remaining sufficient for reliable switching of the reed switch.

Claims (1)

Invention Formula A device for measuring the residual magnetization of products made of ferromagnetic materials, comprising an alternating voltage generator connected to a reed switch placed in a bias winding connected to an indicator, differing 3 13688294 so that, in order to follow the integrator's output, with its response and speed, while off-line connected to the reed switch, the second entered in series are the electronic attenuator connector, the integrator, the converter, the field of the district with the output of the alternator electronic attenuator and sum-voltage, and the output of the adder - with the mater, the second input of which is a magnetic biasing winding.