SU883827A1 - Device for checking magnetic permeability - Google Patents

Description

I

The invention relates to magnetic measurements and can be used to control the magnetic permeability of products made from a weakly magnetic material, in particular, magnetodielectric slot wedges in the working fields of the stator of a three-phase electric chip.

A device for measuring magnetic permeability is known, which contains a magnetization unit, an ISCUE measurement unit, a voltage measurement unit, and a digital frequency ratio meter 1}.

The magnetization unit is powered by a three-phase AC network and any deviations from the normal parameters of this network cannot be accurately monitored by a voltage measurement unit, which is proportional to the phase currents of the magnetization unit. This circumstance reduces the accuracy of control of the magnetic permeability of samples. No ability to smoothly change

Within the necessary limits, the maximum intensity of the magnetization field in the process of carrying out the monitoring, which also reduces the information content and accuracy. control

The aim of the invention is to improve the accuracy of control.

The goal is achieved by the fact that a device for monitoring magnetic permeability, containing a magnetizing unit, an induction measuring unit, a voltage measuring unit and a digital frequency ratio meter, is connected in series with a reference generator of the maximum significant magnitude of magnetization intensity, the intensity – permeability switch, connected to the input of a digital frequency ratio meter and to the outputs of induction and voltage measuring units, as well as a three-phase autotransformer irovki magnetizing current connected to the input device. In addition, in the device, the voltage measurement unit is made in the form of three toroidal induction converters connected in series, covering the phase conductors of the magnetization unit, three integrators, an adder and a Voltage-frequency converter with an output connected to the Intensity permeability switch.

FIG. I is a functional diagram of the magnetic permeability monitoring device; in fig. Figure 2 shows the mutual arrangement of the inductive converters of the voltage measurement unit and the phase conductors of the magnetization unit.

A device for monitoring magnetic permeability consists of a magnetization unit 1, an induction measurement unit 2, a digital frequency ratio meter 3, a digital frequency ratio meter 4, a reference generator 5 of the maximum magnetic field strength, a three-phase autotransformer 6, a switch 7 Permeability-) strength. Induction measurement unit 2 consists of n measuring windings 8, switch 9, integrator 10, converter II voltage, and frequency. The power measurement unit 3 consists of measuring windings 12, integrators 13, adder 14, and converter 15. Voltage-frequency. Toroidal induction converters (figure 2) are made in the form of passive converters of the Rogowski type wound on a nonmagnetic core, topologically equivalent to a torus. In case of a conductor with a measured current (in this case the phase conductor of the reversal magnetization device), Rogowski’s Then the measurement result does not depend on the relative position of ca and a conductor with current, but depends only on the number of conductor penetrations of the conductor and is a multiple of it. All three converters through integrators 13

its secondary windings 12 are connected to an adder 14, the output of which is connected to a voltage-to-frequency converter 15.

The outputs of the induction measurement unit 2, the controversial generator 5 of the maximum value of the stress and the block 3 of the measurement of the tension through the switch 7 Permeability-tension are connected to a digital

the frequency ratio meter 4, at the output of which the result of the control is presented in digital form. With the position of the switch 7 in the position I - control of the relative magnetic permeability of the test samples (in relative units)

t

l, - In in

IG position - control of the relative value of the magnetic magnitude of the magnetisation of samples

N. n

7

max

TO

fH

rn-ax

where and

- magnetic field reversal magnitude; - induction in the sample during measurement;

H

The maximum possible magnetic field magnitude magnetic field with a fully inserted autotransformer 6;

conversion factor

TO

in the induction intensity measurement unit;

TO

- conversion factor or intensity measurement unit;

to

the ratio of the frequency of the reference generator to the maximum value of the voltage;

In N

g „

frequencies from the outputs of blonds for measuring induction, measuring the intensity and the reference generator of the frequency of the maximum value of the intensity;

JM is relative magnetic permeability;

5b is the magnetic field magnetic field strength in relative units,. (0.00-1.00).

The device works as follows.

Samples are fastened in the slots of the inductor of the electric machine. Switch 7 is set to position II (voltage control). According to the digital indicator of the meter 4, the frequency ratio of the autotransformer 6 is set, the magnetic field of the magnetization is required, ranging from 0 to what corresponds to the indicator readings from 0.00 to 1.00, respectively . The EMF taken from the windings 12 of the induction converters are integrated by integrators 13 and fed to adder 14, then the total signal is converted by converting 15 into electrical pulses, the frequency of which determines the amplitude value of the magnetization reversal field and is fed to one input (divisible) digital meter 4 ratio frequencies. At the second input (divider) of this meter, at this position of the switch 7, a signal is received from a bporn generator with a frequency of the torus that determines the maximum possible amplitude value of the magnetic field strength in this magnetic reversal device. The ratio of the frequencies at the inputs of the digital meter 4 relations with the installation of the switch 7 in the position I1-determines the value of jj.

Switch 7 is then set to position I (permeability control). In this case, the signal from the output of converter 15 is fed to the second input of meter 4, and to the first input is fed a signal from converter 1I, whose frequency is proportional to the amplitude value of the magnetic induction in the measured i-th sample, and which is determined by the EMF arising in the corresponding measuring winding 8 induction measurement units

The ratio of the frequencies at the inputs of the digital meter 4 when setting the switch 7 to the position I determines the value of the relative magnetic permeability of the sample i-r when the magnetic field of the magnetization reversal

 max

When all n measuring windings are switched in series, the relative magnetic permeability of all the tested samples is monitored. An indispensable condition for control in the device should be the equality of the conversion factors Kg K, Kntah.

This device can be used to automatically control the relative magnetic permeability of weakly magnetic products, in particular the magnetodielectric groove wedges of the stators of electric machines in the working fields of the toothed zone of the machine. In this case, the automatic removal of families of characteristics is easily realized.

/ H ((n) s) (n) a group of n samples with the output of the control result in digital form on digital printing or graphical building devices.

Claims (1)

1. A device for monitoring magnetic permeability, containing a block magnetization, induction measurement unit, voltage measurement unit and a digital frequency ratio meter, characterized in that, in order to improve the control accuracy, the device is connected in series with a support 1 "max-cl-1 generator of the magnetization polarity, switch Tension permeability connected to the input of a digital frequency ratio meter and to the outputs of induction and voltage measuring units, as well as a three-phase autotransformer for adjusting magnetizing currents, Switched to the input of the device. 2, The device according to claim 1, of which is that the unit is measured and the intensity is made in the form in series of three toro 1dal induction converters covering the phase conductors of a magnetization unit, three integrators, an adder and a converter Voltage-frequency output connected to the voltage-permeability switch. Sources of information taken into account in the examination 1, USSR Copyright Certificate No. 2726758/21, Class G 01. R 33/12, 1979. R