SU1594444A1 - Method of determining resistance - Google Patents

Abstract

The invention relates to electrical measurements and can be used in systems for automatically monitoring and measuring resistance, in particular in electrical circuits of a locomotive. The purpose of the invention is to reduce the measurement time by performing measurements on complex branched series-parallel electrical circuits without breaking electrical connections of the measured resistance with these circuits. The goal is achieved by the fact that from a source of stabilized voltage, a different voltage is applied directly to a test circuit made up of the measured and subsequent resistance, the value of the voltage drop on the next after the measured resistance is measured twice without connecting the reference voltage. resistance and with parallel connection of the reference resistance to the measured one, and the value of the measured resistance is calculated by the calculation formula defined for this measurement method. 1 il.

Description

The invention relates to electrical measurements and can be used in systems for automatically measuring and monitoring active resistance, in particular in electrical circuits of locomotives.

The aim of the invention is to reduce the measurement time by performing measurements in complex branched series-parallel electrical circuits without breaking the electrical connections of the measured resistance with these circuits.

The drawing shows a device that implements the method.

The method consists in that a different voltage from a source of stabilized voltage is applied to a test circuit made up of the measured and subsequent resistances. At the next post-measurement, the voltage drop is measured twice and recorded: the reference resistance is not connected to the measured resistance and, in parallel, the reference resistance is measured by the switching element. The magnitude of the measured resistance is calculated by the equation

sd

with

U ..

- and

  L, 1. l

ten

15

31594444

where RJ is the measured resistance;

Rg - reference resistance; and in - voltage drop on the follower after the measured

resistance R, v, without connection of reference resistance;

Vf (, is the voltage drop at the next after the measured resistance Rj, when the reference resistance RI is connected to the measured one in parallel; I and is the stabilized voltage of the power source. The device; which implements the method, contains an electrical circuit 1 whose resistance

  also a measurement unit 2, a switching source 3 a stabilized voltage with a positive terminal 4 and a minus terminal 5, a reference resistor 6, switching element 7, with output 2 and | Measured connected computing 6jnoK 8.

; The device operates as follows.

; To measure the value of resistance | RJ, the voltage from the source 3 of the stabilized voltage is supplied n; and the circuit consisting of the measured

gd

pi de

20

25

30 or more

(one)

(2)

where and is voltage stabilized

power source 3; EE is the resistance of the reference resistor 6 of the measurement unit 2. From relations (1) and (2), the following expression can be written to determine the measured resistance:

R:

(3)

Thus, according to equation (3), the resistance value in any branched sequential-paral-. Without electrical connections, they can be determined by measuring two voltage drops on the next after the measured R resistance of the SRI RU, without connecting (U /.) and when connecting the reference resistance Ra (U Ri + i)

Rlj and subsequent resistance R; This positive source terminal 4, connected to the first output of the reference resistor 6, is connected to the measured resistance at terminal e | , minus terminal 5 source 3 n: connected to the output followed by the measured resistance R | at terminal 8, the second output of the reference pie3HCTopa 6, through commutation, the element 7 is connected to the connection of the measured R, - and the subsequent resistance Rj at the terminal G.

The voltage drop is measured at the next one after the measured resistance twice:, - the open-closed switching element 7, i.e. without connecting the reference resistor 6, and u |. - when the switching element 7 is closed, connecting the reference 6 source 6 parallel to the measured R,

In accordance with the measurement scheme and taking into account the measurements made of the voltage drops on the resistance R., the following relationships can be written:

five

0

five

0

five

Claims (1)

Invention Formula The method of determining the resistance, which supplies stabilized voltage to the controlled parts of the electric circuit, including series-connected measured and reference resistances, records and compares the voltage drop of the controlled areas when the reference resistance is connected and without connecting the reference resistance, differing from In order to reduce the measurement time, the supply of stabilized voltage is carried out from a direct current source on a series flaxally connected measured resistance and subsequent resistance, and fixing and comparison of voltage drops are performed on subsequent resistance without connecting the reference resistance and connecting the reference resistance in parallel with the measured resistance), and 5 1594444 the rank of the measured resistance R is calculated by the formula R. UR, (uL. - Up.)  to ij. "r% | 4 M, Up. (and - uo.) , to ( where and is the stabilized voltage of the power source; RJ - reference resistance; and |. - voltage drop on the next after the measured M1H5 0 resistance R, when parallel connecting the reference resistance Rj to the measured resistance R ;; io - voltage drop along i following the measured resistance R} "., without connecting the reference resistance.