JPS59126215A - Abnormal state detector - Google Patents

Abstract

PURPOSE:To improve the detection accuracy by deriving a mean of cyclic vibration signals which are below the reference while the reference value is altered according to the level of the vibration signals. CONSTITUTION:A cyclic vibration signal of a detector 1 is fetched into an A/D converter 2 by a signal of a trigger device 3 to convert. After the conversion, a signal from the converter 2 is compared with the reference level computed by reference level arithmetic unit 5 under the control of a frequency identifier 4 according to the level of a drive signal and signals below the reference level are added up at a specified frequency with an arithmetic unit 7 under the frequency indentifier 4 to calculate a mean thereof. Therefore, no accidental large noise mixed is allowed to be untroduced into the unit 7 while the reference level can be automatically altered according to level of the vibration signals thereby enabling accurate calculation of the mean thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention provides period 'I! ! l! The present invention relates to an abnormal state detection device that automatically sets an l/C reference level based on the magnitude of abnormal vibrations having 1/2, and that accurately detects abnormal vibrations by removing signals above the reference level.

Conventional abnormal vibration with synchronization caused by partial discharge etc. 4
By averaging υJ, only the synchronous vibrations are extracted with high accuracy. In order to prevent the overall signal level from increasing due to sudden noise etc. and decreasing the accuracy, the periodic signal is There is a method that captures a waveform with a trigger suitable for its cycle and averages it to eliminate non-periodic signals and extract only periodic signals with high accuracy. In this conventional waveform averaging device, the accuracy decreases as the number of averaging increases, but the problem is that the addition of even a few sudden noises causes the overall level to become sharp, resulting in a significant drop in accuracy.

Therefore, a discriminant pupil called a level discriminator was provided, and the reference level of the level discriminator was manually set to remove sudden noises. However, since the reference level of the level discriminator is manually set, there have been problems such as variations in measurement data depending on the setting position of the reference level.

This invention was made in order to eliminate the drawbacks of these conventional methods, and uses an arithmetic unit in the detection device to determine the basic level of the level discriminator to remove sudden noise when averaging the waveform. By linking and automatically setting according to a certain rule, and by configuring it so that anything exceeding this standard level is not added to the data by 1 or more, the overall level will become sharp due to sudden noise, etc., and accuracy will decrease. It is an object of the present invention to provide an abnormal state detection device f that can eliminate the occurrence of errors and reduce the variation f of measurement data.

An embodiment of the present invention will be described below based on the drawings. That is, in the figure, (l) is a detector that detects a vibration signal having periodicity of each keyaki, (2) is an AD converter that converts the analog signal derived from detector (1) into a digital signal, and (3 ) is a trigger device that generates a trigger signal synchronized with the vibration 1υ” signal in order to cause the AD converter (2) to take in the vibration signal, and (4) is the AD converter (
2) is a number discriminator that determines the number of times of capture, (5) is A
(6) is an AD converter that examines the magnitude of the signal derived from the D converter (2) in time series and calculates a reference level according to the magnitude of the signal. (2)
The signal from the arithmetic unit ft (5) is compared with the reference level of the arithmetic unit vτ (7), and the signal higher than the reference level is detected by the arithmetic unit
), the level discriminator (7) sends signals below the reference level to the arithmetic unit (7), which adds the signals below the reference level judged by the level discriminator (6) a predetermined number of times and calculates the average value. It is an arithmetic device that performs calculations.

With this configuration, the vibration signal having periodicity is not detected by the detector (1), but is detected by the trigger device (8).
) is sent to the AD converter (2) and converted into a digital signal.
), the reference level calculated by the reference level calculation device (5) according to the magnitude of the moving signal is compared with the signal f'' derived from the AD converter (2), and the The signals are added a predetermined number of times by the arithmetic unit (7) K under the control of the number of times determiner (4>) and the average value of these sums is calculated.

Therefore, even if a sudden large noise mixes into the vibration signal, the arithmetic unit (7) K is not introduced, and the reference level is not automatically converted according to the magnitude of the vibration signal.
The average value of vibration signals can be calculated accurately.

As described above, the abnormal state detection device according to the present invention derives the average value of vibration signals having periodicity that are below a standard, and uses this standard value as the magnitude of the vibration signal K l+i>
The accuracy is the same as above.

[Brief explanation of the drawing]

Figure G is a block diagram showing an example of this invention. In the figure, (1) is a detector, (2) is an AD converter, )3) is a trigger device, (4) is a number of times determiner, (5) is a reference level calculation device, (6) is a level determiner, (7) is an arithmetic unit. In the figures, the same reference numerals indicate the same or corresponding parts. Agent Shin Kuzuno - 2d

Claims (2)

[Claims] (1) An abnormal state detection device characterized by deriving the average value of periodic vibration signals that are equal to or lower than the Chatei value and changing the reference value according to the magnitude of the vibration signal. (2) The abnormal state detection device according to claim 1, wherein the vibration signal is converted into a digital signal and is calculated.