RU1822987C - Device for measuring coupling impedance of cylindrical screen - Google Patents

Abstract

Usage: radio-measuring technique. SUMMARY OF THE INVENTION: A device for measuring the coupling resistance of a cylindrical screen comprises external and internal conductors between which the test cylindrical screen (ICE) is coaxially placed. On top of the ICE, the first ferrite tube is placed at the input end, and the second ferrite tube and induction converter are located on the other end. The input end of the outer conductor of the ICE is connected to one terminal of the generator, the other terminal of which is connected to the inner conductor. An additional screen is placed between the ICE and the second ferrite tube and the induction converter, one end of which is galvanically connected to the ICE in the center of the second ferrite tube, and the other with the output end of the external conductor. The output end of the ICE through a load resistor is connected to the inner conductor. The terminals of the winding of the induction converter are connected to an external conductor and an indicator. 1 ill. SB with

Description

The invention relates to a radio measurement technique and can be used to measure the coupling resistance of cylindrical shields, and in particular cable shields.

The aim of the invention is to reduce the measurement error, increase the sensitivity and noise immunity.

The drawing shows a general view of a device for measuring the coupling resistance of a cylindrical screen.

The device comprises an internal (VP) conductor 1, an investigated cylindrical screen, an external conductor (GNP) 3, an input end 4, a generator 5, an output end 6 of a GNP 3, a load resistor 7, an induction converter 8, consisting of a set

toroidal cores 9. separated by dielectric washers 10, and windings 11 from copper insulated wire, two ferrite tubes 12. 13, additional screen 14, input end 15 of additional screen 14, output end 16 of additional screen 14. first end 17 of the induction winding 11 converter 8, the second end 18 of the winding 11 of the induction converter 8, indicator 19.

The generator 5 is connected between the inner conductor 1 and the ICE 2 at the input end 4 of the coaxial pair formed by them, at the output end 6, a load resistor 7 is connected to this coaxial pair. Inside the GNP 7, the ICE 2 is coaxial

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placed the induction converter 8, two ferrite tubes 12, 13 and an additional shield 14. The induction converter 8 is made on toroidal cores 9 with high magnetic permeability, separated by dielectric washers 10, The winding 11 of the induction converter 8 contains several turns of insulated copper wire. The first end 17 of the winding 11 is connected to the external conductor 3, and its second end 18 through the external conductor 3 is displayed on the indicator 19. The additional screen 14 is made of non-magnetic material in the form of a continuous metal pipe. The input end 15 of the additional screen 14 is connected to the external conductor 3. The output end 16 of the additional screen 14 is connected to the ICE 2 and located inside the ferrite tube 13. The other ferrite tube 13 is located at the input end 4 over the ICE 2 connected to the external conductor 3. The total length of the ferrite - the outlet tubes 12, 13 should be less than the distance between them. Induction converter 8 is located on top of an additional screen 4 between the ferrite tube 13 and the end 15 of the outer conductor.

The device operates as follows.

A generator 5 is connected to the input of a coaxial pair formed by VP 1 and ICE 7. At the opposite end, this coaxial circuit is connected to a load resistor 7. Generator 5 generates a current in this circuit. In turn, this current creates on the outer surface of the ICE 2 EMF E, and on the outer surface of the additional screen 14 EMF E2

Ei IZcBllt

E2 I Zco2 12,

where Ei - EMF on the outer surface of ICE 2, B;

E2 - EMF on the outer surface of the additional screen 14, B;

1 - current in the circuit VP-ICE 2, A;

ZCBI - communication resistance of ICE 2, Ohm / m;

Zce2 is the communication resistance of the secondary screen 14, Ohm / m;

And - the length of the ICE 2 between two ferrite tubes 12, 13, m;

h is the length of the additional screen 14, m.

Since Zce2 ZCBi- EL, then, under the influence of the EMF E1 in the induction transducer 8, made on toroidal cores 9 with high magnetic permeability, separated by dielectric washers 10, with a winding from a copper insulated wire 11, a voltage is created, which is measured indicator 19. At a given generator level

5 and the specific transfer function of the induction converter 8, the value of the communication resistance of the ICE 2 is determined from the measurement result.

Attenuation of spurious magnetic and

electrical connections between the circuits of the generator 5 and the indicator 19 due to the additional screen 14 and one ferrite tube 13, allowed to significantly reduce the stray signal in the circuit of the indicator 19. Another ferrite tube 12 provides effective attenuation of electromagnetic interference from external sources that accidentally leaked into the external conductor 3. By appropriate selection of the number

windings of the winding 11 of the induction converter 8 are aligned with the input of the indicator 10 and, therefore, the sensitivity of the device is increased.

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Claims (1)

The claims A device for measuring the coupling resistance of a cylindrical screen, containing coaxially arranged an external conductor in the form of a metal pipe and an internal conductor for interposing a coaxially examined cylindrical screen (ICE) between them. generator, one output of which is connected to the input end of the inner conductor, and the other is a terminal for connection to the input end of the ICE and the external conductor, a load resistor one of which is connected to the output end internal conductor, and the other is a terminal for connection to the output end of the ICE, as well as an induction converter and an indicator, characterized in that, in order to reduce the error of measurements, increasing sensitivity and noise immunity, the induction converter is made in the form of a set of toroidal ferrite cores separated by dielectric washers, and windings, as well as two ferrite tubes and an additional screen made in the form of a continuous metal pipe made of non-magnetic material, with the first ferrite tube placed inside the outer conductor at its inlet end, and the second ferrite tube and induction converter are placed sequentially inside the outer conductor at its output end, an additional screen inside the second ferrite tube and the induction converter, the input end of the additional screen is the input for connecting the ICE in a plane located in the middle is connected to the output end of the low-voltage conductor, while one end of the coil of the induction converter is connected to the external conductor and the other - with WMO not the second ferrite tube, but the output of the 5th house indicator. 72 / J9 y