SU1322094A2 - Device for measuring dynamic parameters of rotating parts of power installations - Google Patents

Abstract

A device for measuring the dynamic parameters of rotating parts of power plants comprises a rectangular voltage generator 1, a differential current amplifier 2 with a differential input, a transformer-type current-collecting current collector 3 comprising a fixed winding 4, a feedback winding 5 and a movable winding 6, a strain gauge 7, transformer converter 9 with primary winding from sections 10 and 11 and secondary winding 12, capacitor 13 and recording unit 14. The device has high measurement accuracy by improving ratio signal - noise ratio at the input of the recording unit 14. The 1-yl. from € ate r L / .9 12 lit

Description

The invention relates to information-measuring technology and can be used to measure dynamic parameters (pressure, deformations, vibrations) of rotating parts of power plants - electric machines, gas turbine engines, etc. and is an improvement of the invention by author. No. 1026013,

The purpose of the invention is to improve the measurement accuracy of the device by improving the signal-to-noise ratio at the input of the recording unit.

The drawing shows a block diagram of the device.

A device for measuring the dynamic parameters of rotating parts of power plants comprises a rectangular voltage generator 1, a direct current amplifier 2 with a differential input, a non-inverting input of which is grounded, a transformer-type current-carrying current collector 3 containing a fixed winding 4, a feedback winding 5, The movable winding 6, to the terminals of which is connected a strain resistor 7, located on the rotating part 8 of the power plant, a transformer converter 9 with a primary winding consisting of two subsequently connected sections 10 and 11, and secondary winding 12, capacitor -13 and recording unit 14, the first output of the rectangular voltage generator 1 is grounded, its second output is connected to the first output of the feedback winding 5, the second output of which is connected to the inverting the input of the amplifier 2 DC, the output of which is connected to the first output of the stationary winding 4, the second output of which is connected to the ground bus through counter-connected sections 10 and 11, the capacitor 13 is connected in parallel to the section 11 ne The winding coil of the transformer converter is 9, and its secondary winding 12 is connected to the inputs of the recording unit 14.

: - ..

The device works as follows.

An electric signal in the form of a rectangular voltage from the output of a rectangular voltage generator 1 through the feedback winding 5 is fed to the inverting input of the amplifier 2. Direct current and drives a current 1d in: the fixed winding 4 of the power supply

current collector 3 transformer type. The current i induces a voltage in the fixed winding 6 and the feedback winding 5. Since the feedback winding 5 is connected in series with the output of the rectangular voltage generator 1, then, with appropriate feedback phasing of the feedback winding 5, the voltage induced in it will always be out of phase with the output voltage of the rectangular voltage generator 1.

The difference signal is fed to the inverting input of the amplifier 2 of direct current and at a sufficiently large amplification factor of the voltage tends to zero. Thus, in windings 5 and 6, voltages similar in shape to the voltage at the output of the rectangular voltage generator 1 are induced. Section 10 and 11 of the primary winding of the transformer Converter 9 is connected in series with the fixed winding 4 of the supply current collector 3.

The current i of the winding 4 varies linearly within the limits of each half-period of the rectangular voltage. The repetition period of the rectangular voltage is chosen much longer than the period of the lower harmonic of the controlled frequency range of the dynamic parameter and is tens and hundreds of milliseconds. Thus, TOKI i is periodic. linear varying time function with a fundamental frequency of 5 10 Hz.

The reactance of a capacitor 13, with a suitable Selection of the value of its capacitance, may have a significant value for the first and a number of higher harmonics of the frequency spectrum of the current i ,. In this connection, practically all current i flows around all sections 10 and

11 of the primary winding of the transformer 9, connected in series and counter. As a result of this switching on of sections 10 and 11, the magnetizing forces of the primary winding of the transformer transformer 9 are mutually compensated and in its secondary winding 12 the voltage is not induced, i.e. There is no square signal at the input of the recording unit 14.

The strain gauge 7, located on the rotating part 8 of the power plant ;;

ki, is under the influence of a controlled parameter. A change in the resistance of the strain gauge 7 leads to a change in the current i flowing through it, and accordingly to a change in the current i flowing through the serially connected sections 10 and 11 of the primary winding of the transformer converter 9, The reactance of the capacitor 13 has a small value for high frequency current strain gauge 7 under the influence of a dynamic parameter. Consequently, the informative component of the current i is closed through the capacitor 13, the section 11 of the primary winding of the transformer converter 9 goes to min, and the voltage at the controlled variable dynamic frequency is induced in its secondary winding 12.

Amplitude frequency response of the transformer converter

9 when idling the secondary winding 12 and the same number of turns of the sections

10 and 11 of the primary winding has the form

W (w) wMR

VR2 + (uJL-1 / u) C) 2

de U) is the circular frequency of the electrical signal;

M - mutual inductance between one of the sections 10 and 11 of the primary winding and the secondary winding 12 of the transformer converter 9. the inductance of section 10 or 11;

L

C - capacitor capacitance 13;

Editor A. Sabo

Compiled by V. Bykov

Tehred A. Kravchuk Proofreader G, Reshetnik

Order 2853/36 Circulation 693 Subscription

VNIIGSh of the USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

with O 5 0

five

0

35

0

R - active resistance of section 11.

According to this formula, W (LL) O with and W (w) MR / L with. This means that the transformer converter 9 suppresses the low-frequency signal and passes the high-frequency signal, i.e. is a high pass filter. Thus, at the input of the recording unit 14, there is no square noise in the presence of a high-frequency informative signal about a controlled dynamic parameter, which is how the objective of the invention is achieved.

Thus, the proposed device has a higher measurement accuracy by improving the signal-to-noise ratio at the input of the recording unit 14, which makes it possible to further simplify the recording unit 14 by eliminating the means of suppressing square noise, to simplify setup and operation of the device.

Claims (1)

Invention Formula A device for measuring the dynamic parameters of rotating parts of power plants according to ed. St. No. 1026013, characterized in that, in order to improve measurement accuracy — by improving the signal-to-noise ratio at the input of the recording unit, the primary winding of the transformer converter is made of two sections connected in series, one of which is. ryh shunted capacitor.