SU1527486A1 - Multichannel transducer for dynamic measurements of rotary objects - Google Patents

Abstract

The invention relates to measurement technology and can be used to measure the dynamic parameters of rotating parts of machines. The aim of the invention is to improve the accuracy due to the constant amplitude of the current in the rotating strain-resistive circuit. The current generator 13 and the third fixed winding 11, made in the form of two sections with an equal number of turns, connected back-to-back, prevents the selection of precision resistors in each measuring channel. The voltage of the strain gauge circuit does not depend on the resistances R ₁ , R ₂ , the values of which are thermally dependent, and therefore it remains constant in amplitude with a change in the temperature of the current collector 8. 1 Il.

Description

one

(21) 4333381 / 25-28

(22) 11/26/87

(46) 12/07/89. Bul Number 45

(71) Ufa Aviation Institute. Sergo Ordzhonikidze

(72) A.V.Gubin, V.F.Protsenko, V.A.Maltsev and S.S.Toropov

(53) 531.781.2 (088.8)

(56) USSR Copyright Certificate No. 1201676, cl. From 01 to 7/16, 1983.

USSR Author's Certificate No. 1016668, cl. From 01 to 7/16, 1987.

(54) MULTI-CHANNEL DEVICE OF DYNAMIC MEASUREMENT DIFFERENCE ON ROTATING OBJECTS

(57) The invention relates to measurement technology and can be used to measure the dynamic parameters of rotating machine parts. The aim of the invention is to improve the accuracy due to the constant amplitude of the current in the rotating strain-resistive circuit. The current generator 13 and the third fixed winding 11, made in the form of two seconds with an equal number of turns connected in opposite directions, eliminates the selection of precision resistors in each measuring channel. The voltage of the strain-resistive circuit does not depend on the resistances K, H, whose values are thermally dependent, and therefore it remains constant in amplitude with a change in the temperature of the current collector 8. 1 Il.

(L

ate to

sc about:

31527А86

The invention relates to a measurement technique and can be used to measure the dynamic parameters of rotating machine parts.

The aim of the invention is to improve the accuracy due to the constant amplitude of the current in the rotating tensor-resistive circuit.

The drawing shows a block diagram d of the device.

A multichannel device for dynamic measurements on rotating objects contains a stationary part, each channel of which consists of, in turn, j consequently connected generator of rectangular pulses, adjustable amplifier 2 and differential amplifier 3, series-connected reference voltage source 4 and 20 comparison unit 5, sequentially connected differentiating unit 6 and the recorder 7, the current collector 8 of the transformer type with three fixed windings 9-11 and one movable 25 winding 12, the first. Vizny windings 9-11 are connected to the common wire, the second output of the first fixed winding 9 is connected to the output of the differential amplifier 3 and to the input of the differentiating unit 6, the second output of the second fixed winding 10 is connected to the inverting input of the differential amplifier 3, the third fixed winding 11 is made the form of two sections with an equal number of turns, connected counter-sequentially, the second output of the third unsupportable winding 11 is connected to the second input of the comparison unit 3, and a current generator 13, one output of which is connected to the second The third terminal of the fixed winding 11, and the other with a common wire and a movable part consisting of a strain gauge 14, the conclusions of which are connected to the conclusions of the movable winding 12.

The device works as follows.

The direct voltage supplied to the non-inverting input of the differential amplifier 3 from the generator 1 of rectangular pulses through the adjustable amplifier 2 causes about 11 in the first fixed winding of the supply current collector 8. This ok induces in all the windings 9-12 of the receiver 8 of the mutual induction voltage . Voltage arising

thirty

35

45

50

55

but, on the contrary, on the contrary, it is the same as that of the rip

n

gd

d

0 5 o

0

five

45

50

at the terminals of the feedback winding 10, is compared at the input of the differential amplifier 3. The differential signal supports the current 11 of the first fixed winding 9. If the gain of the differential amplifier 3 is sufficiently high, the difference signal tends to zero, and therefore, the voltage induced in The feedback winding 10 approximates a rectangular shape. The same shape has the voltage induced in the rotating winding 12, which is coupled with the same magnetic flux as the feedback winding 10. The rectangular voltage from the rotating winding 12 is supplied to the moving part (FC). The stationary winding 11 is made in the form of two sections with an equal number of turns, wound bifillary and connected back-to-back. Therefore, the voltage at its terminals will be absent. A change in ambient temperature causes a change in the magnitude of the distributed resistances of the windings 12 and 11 and the connecting terminals of the inverter. With a constant signal on the non-inverting input of the differential amplifier 3, the voltage induced in the winding 12 will also be constant in level. Consequently, any temperature changes in the resistance of the inverter cause a change in the value of the inverter current, which leads to a change in its sensitivity. To stabilize the current value of the inverter in the proposed device, a current generator 13 is used, the third stationary winding 11, the source 4 of the reference voltage and the comparison unit 5 are stationary. These elements, together with the adjustable amplifier 2 and the differential amplifier 3, form an automatic system for stabilizing the IF current, which operates as follows.

The voltage on the resistance of the moving part is

R

Un ,, 12-R

Frequency converter

Frequency converter

W c

R.-RHM

(one)

five

where 12 is

E2 in a rotating winding in a rotating winding

current 12;

emf

12;

distributed resistance

rotating winding 12;

To „„ - resistance of the movable part (in the simplest case, the resistance of the resistor 14).

The magnitude of the EMF in the winding 12 is equal to

and.

eiix

but --

(2)

where Uj, is the voltage at the output of the differential amplifier 3; n - the transformation ratio of the windings -9-12.

In turn u

and

j at k - 00

where K is the gain of the differential amplifier 3, and

15

and

in

and u to ,,

(3)

where and is the voltage at the output of the unit

5 comparisons; K, j - its diff-20 transfer coefficient

 of the potential amplifier 3. The voltage at the output of the comparison unit 5 is equal to

and,

to a- -t-ioR,),

(four)

where is the block transfer ratio

5 comparisons;

Up is the voltage at the output of the source 4 of the reference voltage; IJ, - the amplitude of the current generator 13; K, is the distributed resistance of the third fixed winding 11. Substituting (2) - (4) in (1) we have

,) - “be

and

,,(and,

pch

P

(7 - R "4)

In order for the voltage U

was constant when the temperature of the rotating winding 12 changes, it is necessary to enforce the equality

and „„ R,

R

pch

R,

(6)

Substituting (6) into (5), we get

and

K ,, K

pch

and.

(7)

From (7), it follows that the voltage of the strain-resistant circuit does not depend on the resistances K, K, whose values are thermally dependent. Therefore, it remains constant in amplitude as the temperature of the current collector 8 changes.

Claims (1)

Invention Formula Multichannel device for dynamic measurements on rotating 10 objects containing a fixed part, each channel of which consists of a series-connected square pulse generator, an adjustable amplifier and a differential amplifier, a series-connected reference voltage source and a comparison unit, a series-connected differential unit and a recorder, the output of the comparison unit is connected to the second input of an adjustable the amplifier, and the output of the differential amplifier is connected to the input of the differentiating unit, the current collector of the transformer current with three movable and one movable windings, the first terminals of the fixed windings are connected to a common drive, the second output of the first fixed winding is connected to the output of the differential 30 of the amplifier and the input of the differential unit, and the second output of the second fixed winding is connected to the inverting input of the differential amplifier, and a movable part consisting of (5) 35 tekresistor, the conclusions of which connected to the terminals of the movable winding, characterized in that, in order to increase the accuracy due to the constant current amplitude in 40 of the rotating strain gauge circuit; the conclusion of the third fixed 50 windings, and the other - with a common drive. 1527A86