SU754213A1 - Electric discharge device for measuring rotating shaft run-out - Google Patents

Description

The invention relates to measuring equipment and is intended to measure the beat of a rotating shaft.

The electrical discharge device for measuring the beat of rotating shafts is known, which contains a sensitive element made in the form of an electrode installed at a distance from the surface of the rotating shaft, a reference voltage source, a power supply circuit and a measuring device Ш.

This design has a low toodnost, ¹ ® since the sensitivity is inversely proportional to the square of the distance from the surface of the rotating shaft to the electrode.

The purpose of the invention is to improve the accuracy of measurement of the beat of the rotating shaft.

This goal is achieved by the fact that the power supply circuit contains two capacitors, a thyristor and four resistors, two of which are connected in series between the reference voltage source and the measuring device, and their middle point is connected through one of the condensate to the common point, and the second is connected in parallel to the measuring device.

2

a capacitor and a series-connected third resistor and a thyristor, the control input of which is connected to the electrode and through a fourth resistor with a common point.

The drawing shows a schematic diagram of the device.

The device contains a sensitive element, made in the form of an electrode 1, installed at a distance from the surface of the rotating shaft 2, the source 3 of the reference voltage, the measuring device 4 and the power supply circuit containing two capacitors 5 and 6, a thyristor 7 and four resistors 8,9,10, 11, two of which 8 and 9 are connected in series between the reference voltage source and the measuring device 4, and the middle point of the resistors 8 and 9 is connected via a capacitor 5 with a common point 12. Parallel to the measuring device 4 there are included / second capacitor 6 and been consistent connected to a third resistor 10 and the thyristor 7, the control output of which is connected to the electrode 1 and through the fourth resistor 11 to the junction 12.

The device operates in two modes, in

754213

four

3

which at open branches at points a and ^ allows you to measure the change in the length of the interelectrode gap δ when the shaft rotates at any point in time, and with closed branches - the difference between the minimum values of the length of the gap in dynamics and static.

The device works as follows.

In the first case, the capacitor 6 is periodically charged and discharged through the 10th interelectrode gap with a frequency much higher than the shaft rotation frequency, moreover, the voltage from the capacitor 6 is fed to a measuring device (oscilloscope). For a more accurate determination of the magnitude of the discharge voltage 15 between the output of the device and the measuring device, a voltage divider is turned on, consisting of a series-connected resistor and a volt-free voltage. Determination of the size of the inter-electrode gap and its change 20 is made according to the previously obtained (theoretically or experimentally) dependence of the discharge voltage on the length of the gap between the electrodes.

In the second case, a periodic 25 charge of the capacitor 5 occurs, through the resistor 9 of the capacitor 6 and their discharge through the interelectrode gap 5. Thyristor 7 serves to reduce the time and discharge the capacitors more completely. Introduction to the circuit of the device of the capacitor 30 (and thyristor 7) allows the sweat to obtain the frequency of charge and discharge of the capacitor 6 much less than the frequency of rotation of the shaft. Therefore, the discharge occurs at the same

the instantaneous position of the shaft 2 relative to the stationary electrolyte 1, both when the shaft rotates at a higher speed (dynamics) and when it rotates slowly (static).

Claims (1)

Claim An electron-discharge device for measuring the beat of a rotating shaft, containing a sensitive element made in the form of an electrode installed at a distance from the surface of the rotating shaft, a reference voltage source, a power supply circuit and a measuring device, characterized in that, in order to improve the accuracy, the power circuit contains two capacitors , a thyristor and four resistors, two of which are connected in series between the reference voltage source and the measuring device, and their average meter is connected through one of the condensations Hur to the common point, and parallel to the measuring instrument includes a second capacitor connected in series and a third resistor and thyristor control input of which is connected to the electrode and via the fourth resistor to the common point.