SU1317276A1 - Device for performing dynamic measurements of rotating objects - Google Patents

Abstract

This invention relates to a measurement technique. The purpose of the invention is to improve the accuracy by compensating for the periodic component and extracting the informative signal without distorting its spectrum. This goal is achieved by the fact that the device is equipped with series-connected integrator 10 and adder 11. Integrator 10 serves to form the subtractive (compensating) voltage and. The adder 11 adds the voltage and, with the voltage U, coming from the output of the amplifier 2 DC. The result of this addition is the compensation of the periodic component (interference) in the voltage U and the selection of the informative signal without distorting its spectrum. 2 pcs.

Description

The invention relates to a measurement technique, namely, strain gauge transducers for measuring time-varying mechanical quantities on rotating parts of power packs, and can be used to measure deformations.

The purpose of the invention is to improve the measurement accuracy by compensating for the tO periodic component and extracting the informative signal without distorting its spectrum.

Figure 1 presents the block diagram of the device; Fig. 2 shows voltage diagrams 15.

A device for dynamic measurements on rotating objects contains a series-connected rectangular pulse generator 1 and 20 DC amplifier 2, an inductive type current collector 3 with stationary windings 4-6 and a moving winding 7, in which one winding terminal 4 is connected to the amplifier output 2, one output of the winding 5 is connected to the inverting input of the amplifier 2, one output of the winding 6 is connected to the input of the temperature stabilization unit 8 of the current of the strain gauge 9, the second 30 leads of the windings 4-6 are connected to the common wire, and the conclusions windings 7 are connected to a strain gauge 9 placed on the object of rotation (not shown) connected in series 35 integrator 10 and adder 11, the output of which is connected to recorder 12, another input of adder 11 is connected to the output of amplifier 2 of direct current, input of integrator 10 40 is connected to the output of the generator 1 of rectangular pulses, the input of which is connected to the output of the block 8 of temperature stabilization.

45

The integrator 10 is implemented, for example,

on the basis of an operational amplifier, in a negative feedback of which a variable resistance and a capacitor are connected in series. Q

The device for dynamic changes on rotating objects works as follows.

Voltage in the form of long-lasting rectangles from the output of the generator of rectangular pulses is applied to a non-inverting input of a direct current silicon 2 and is attached to a fixed winding 4,

causing a current in it i. This current induces in the fixed windings 5 and 6 and in the movable winding 7 of the current collector 3 a mutual induction voltage. The voltage appearing at the fixed winding terminals. 5 is fed to the inverting input of the DC amplifier 2, where it is compared with the voltage acting on its non-inverting input. With a sufficiently high gain over the voltage of the dc amplifier 2, the difference signal tends to zero. This means that in a fixed winding 5 a voltage is formed that is close in shape to the voltage at the output of the generator 1 of rectangular pulses, and consequently, the same voltage will also be formed in the windings 6 and 7, the turns of which are coupled with the same magnetic flux as coils of the winding 5. When the ambient temperature changes, the ohmic resistance of the turns of the movable winding 7 changes. This resistance is connected in series with the strain-resistor 9, as a result of which the value of the current i flowing through sensor cell 9, and therefore the sensitivity of the circuit to the measured mechanical value changes.

To eliminate the temperature effect on the sensitivity of the circuit, a block 8 of temperature stabilization of the current of the strain gauge 9 is used, the input of which receives a voltage from the non-mobile winding 6, where it is compared with the reference voltage. The difference signal from the output of the temperature stabilization unit 8 is fed to the control input of the square pulse generator 1, changing its output voltage level in the desired direction.

In order to maintain a constant voltage within each half-cycle in the moving winding 7, the magnetizing current of the fixed winding 4 varies linearly. This current creates a voltage drop across the active resistance of the fixed winding 4, which also varies linearly in each half-period of the rectangular voltage U, (Fig. 2a), generated by the square-pulse generator 1. In addition to the magnetizing current, the current i (the fixed winding 4 includes the reduced current of the moving

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(rotating) winding 7, having a rectangular shape, whose vertex is modulated by changing the resistance of the strain gauge 9, under the influence of a controlled quantity. The total current i creates a voltage drop across the active resistance of the fixed winding, and the output of the DC amplifier 2 is the voltage U (Fig. 2U.

To remove the informative component of the voltage U from its linearly varying sections, an adder 11 is used, at one of the inputs of which the voltage Uj is fed, from the output of the DC amplifier 2. The second input of the adder 11 is supplied with the voltage Uj (Fig. 26) from the output of the integrator 10. The compensating voltage U is the same in shape with the voltage U, it is out of phase with it and does not contain an informative component caused by a change in resistance of the strain gauge 9 under the influence controlled value. The voltage shaping operation Uj is performed by the integrator 10.

The resulting voltage Uj at the output of the integrator 10 is shown in Fig. 26. This voltage is fed to the input of the adder 11, where it is subtracted from the voltage U coming from the output of the DC amplifier 2.

The difference signal of voltages Uj and u is the informative component of the voltage U (Fig.

172764

22.) and enters the input of the recorder 12.

Claims (1)

Formula invented and A device for dynamic measurements on rotating objects, comprising a series-connected square pulse generator and direct current amplifier, temperature stabilization unit, the output of which is connected to the input of a square pulse generator, current collector Three fixed and one movable windings, the first fixed winding bridge is connected to the DC amplifier output, the second fixed winding terminal is connected to the inverting input of the DC amplifier, the third fixed winding terminal is connected to the input of the current stabilization unit, the second fixed windings of the static windings are connected with a common drive, a strain gauge connected to the output of the movable winding, and a recorder, characterized in that, in order to improve accuracy, it is equipped with series-connected integrator and adder, the output of which is connected to the recorder, another adder input connected to the output of the DC amplifier, and the input of the integrator is connected to the output of the generator mogol-. impulses. Xv x r r CHA., L | / CLL A LLL / MUCH / Editor K. Voloshchuk Compiled by E.Schelina Tehred A. Kravchuk Proofreader V. But ha Order 2412/36 Circulation 677 Yodpisnoe VNIIPI USSR State Committee for inventions and discoveries - 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 (pus.i