SU372523A1 - ALL-UNION - Google Patents

Description

one

This invention relates to a measurement technique.

A device for determining the temperature coefficients of the magnetic permeability of toroidal samples is known, comprising a measured sample placed in a heat chamber with a multi-turn winding and a measuring device, such as a self-oscillating generator, in which the sample is connected to the resonant circuit. If the temperature changes in the heat chamber, the magnetic permeability of the sample and the oscillation frequency of the self-oscillating generator change. The frequency increment, measured by a frequency meter, is used to determine the increment of the magnetic permeability of the sample.

When using a known device, a change in temperature leads to a complicated change in the size of the multi-turn winding, as a result of which the inductance of the winding changes independently of the change in the magnetic permeability of the sample. A change in the inductance of the winding can be comparable to the increment of inductance due to a change in the magnetic permeability of the sample. As a result, the first masks the second, which reduces the measurement accuracy, since it is impossible to take into account the increment inductance of the winding in the known device as an amendment due to the instability and uncertainty of its magnitude.

The proposed device is characterized in that, in order to improve the measurement accuracy, it is equipped with a coil of communication covering the sample under study and a core with a multiturn

winding, located outside the heat chamber, and the multi-turn winding of the core is connected to the input of the self-oscillator. The connection coil is made rigid and coaxial, while the end of the connection coil on the heat chamber side is removable.

The device contains a measurable sample / in heat chamber 2, a self-oscillating generator 5 connected to the input of the frequency meter 4, a turn of communication 5 with a removable cover 6, tightly

covering the sample in the heat chamber and the core of the step-up transformer 7 outside the heat chamber, increasing the winding 8, connected to the input of the self-oscillating generator.

With a change in temperature, the magnetic permeability of the obase changes / its inductance changes accordingly. A - OBm + A obr- The increment of inductance brought to the input of the generator is equal to

(ALo6M + ALo6p) ", where p is the transformation ratio of the step-up transformer formed by the outer ring of the link 5, the core 7 and the step-up winding 8. By the increment often / you recorded

the frequency meter is determined

3

M

s dg

And tk

dg

where A (l is the increment of permeability;

LH - temperature increment; Tfez ,, TftH. -temperature coefficients of inductance and permeability.

The increment of inductance at the input of a self-oscillating generator in a known device is (ALo6p) + ALo6M. If, then the sensitivity of the proposed device is not inferior to the sensitivity of the known. Due to the fact that the winding is on a single turn sample, a rigid structure and with a removable cover, it is possible to determine its temperature coefficient in the absence of the TftL sample of the sample and take it into account as a constant correction. At the same time, the measurement accuracy is greatly improved. In order to reduce the inductance of the scattering during the transformation of the inductance into the circuits of the self-oscillating generator, the coil of communication is made cylindrical coaxial, tightly adjacent to the surfaces of the sample to be measured and the core with step-up winding.

Г, 1обр or - ТИ In general, this device allows to increase the measurement accuracy due to

taking into account the temperature increments of the winding inductance without reducing sensitivity. The inductance of the dissipation in the device is reduced due to the use of a cylindrical coaxial coil of communication that fits tightly to the sample / and core 7 with a winding 8 over all their surfaces.

Subject invention

Claims (2)

1. A device for determining the temperature coefficients of the magnetic permeability of toroidal samples containing a measured sample placed in a heat chamber with a winding included in the resonant circuit circuit of a self-oscillating oscillator, the output of which includes a frequency meter, characterized in that, in order to improve the accuracy measurement, it is equipped with a coil connection, covering the sample under study and a core with a multi-turn winding, located outside the heat chamber, and the multi-turn core winding is connected to the input of the self-oscillating generator. 2. The device according to claim 1, characterized in that the connection coil is rigid and coaxial, and the end of the communication coil on the heat chamber side is removable.