SU678433A1 - Method of calibrating magnetoelectric speedometers - Google Patents

Description

one

The invention relates to a technique for controlling and regulating and can be used for calibrating magnetoelectric velocity meters.

Nowadays, permanent fl. Magnets are widely used in the technique of measuring motion parameters. The closest in technical essence and solvable problems is the method of calibrating magnetic type speedometers, in which the velocity gauge is set at a stable speed, its electrical output signal is measured, a constant magnetic field is applied to the magnet and its magnitude is gradually changed to obtain an electrical signal in which the indication of the arrow of the device corresponds to the rotational speed of the magnet 2. The disadvantage of this method is that the magnetic system has an effect on the indications device, as even if the current flowing in the winding of the external magnetic system is equal to zero, the demagnetizing field is not completely eliminated due to the residual magnetization of the subject. Residual magnetic field of the external magnetic system

on the magnet of the instrument being calibrated, changes its magnetic state. As a result of this indication of the instrument being calibrated under the conditions of the complete absence of an external magnetic field will differ from those obtained in the calibration process in a known manner, which is the source of the error of the latter. Besides

In addition, the state of the magnet of the instrument being calibrated, subjected to a demagnetizing field with an unchanged polarity, depends on the curve of the particular cycle of the hysteresis loop,

5 which is characterized by instability during single cycles of demagnetization or magnetization. Therefore, when using a known calibration method, the position of the operating point

The 0 magnet of the instrument to be calibrated, which characterizes its magnetic state, after being subjected to a demagnetizing field with a non-changing polarity, is distinguished by a considerable uncertainty. . Therefore, the arrow indications of the instrument being calibrated in this case also are characterized by considerable uncertainty. So the uncertainty of the magnetic

Claims (2)

The condition of the magnet calibrated by boron, after demagnetization only by a magnetic field with non-changing polarity, makes it difficult to obtain instrument readings that meet the specified tolerance, which ultimately increases the duration of the calibration process. . The chain of the invention is improved calibration accuracy. The goal is achieved by using a known calibration method based on demagnetizing a magnet rotating at a certain speed of a calibrated device by applying a magnetic field with a constant polarity on it and smoothly varying the DC current flowing to the winding of the external magnet to a value at which the indication of the instrument's arrow will correspond to the number of revolutions of the magnet, an alternating magnetic field is imposed on the constant magnetic field and smoothly reduces its amplitude to zero. The drawing shows a diagram of a demagnetizer for carrying out the described method. An external magnetic field with inconstant polarity is superimposed on the magnet of the instrument pai rotating at a certain speed. Using the setting knob 1, the output current of the source 2 smoothly increases to a value at which the readings of the instrument to be calibrated correspond to the number of revolutions of its magnet, after which the key 3 is opened. In this case, the coil of the external magnet L and the capacitor C form a damped oscillatory circuit. The energy stored in the reactive elements (L, C) of the circuit ,. causes the occurrence of alternating current in it with a decreasing 7 exponentially amplitude. This current creates in the external magnetic system an alternating magnetic field with a decreasing amplitude, which completely demagnetizes it, eliminating 3 thereby the effect of the residual magnetic induction of the external magnetic field. topics on the instrument arrow. At the same time, the phenomenon of accommodation is observed, by which the properties of the magnet of the instrument being calibrated are stabilized, i.e. the uncertainty of its magnetic state is reduced, which ultimately reduces the duration of the calibration process. The use of the described method of calibrating magnetic-type devices for measuring motion parameters allows creating an alternating magnetic field with a decreasing amplitude in an external magnetic system, after exposure to a non-varying polarity field. Increase the accuracy and reduce the calibration time. As a result, labor productivity, for example, in the mass production of magnetic type speedometers, increases by 10%. Claims The method of calibrating magnetoelectric velocity meters, in which a meter is given a specific speed, its output signal is measured, is permanently superimposed on it. This magnetic field is gradually changed to obtain the desired output signal, characterized in that., in order to improve the calibration accuracy, an alternating magnetic field is applied to a constant magnetic field and its amplitude is gradually reduced. Sources of information taken into account during the examination 1. Permanent magnets. Under, ed. L.Sh.KaErnovskogo, M.-L., 1963, p. 117-120. 2. USSR author's certificate number 373628, cl. G 01 R 21/02, 1973.