JPH03150425A - Vibration detector - Google Patents

Abstract

PURPOSE:To improve the detection accuracy by detecting the error between the electric signal of a vibration detector and mechanical vibration, correcting the electric signal with the error signal, and adding its corrected signal and electric signal. CONSTITUTION:The detection AC signal e1 from the vibration detector 10 is sent to a linearity correcting device 20, an amplifier 21, a correcting amplifier 22, and a comparator 23 as an error detector through a rectifying and smoothing circuit 11 and the amplifier 22 where a correcting signal e5 determined according to the characteristics of the detector 10 is stored is connected to a switch 26. Then the comparator 23 closes the switch 26 when a DC signal e2 of the circuit 11 is larger than a set value e3 and sends a signal e5 to a 1st adder 24, which sends the sum signal to a 2nd adder 25 to adjust a measurement range, thereby obtaining a standardized reference signal e7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vibration detection device, and particularly to a vibration detection device for detecting the amount of vibration of a rotating shaft or the like.

(Prior Art) Generally, when a rotating shaft, a bearing stand, etc. of a rotating machine such as a steam turbine generates vibrations exceeding a predetermined level during operation, the performance of the steam turbine decreases or mechanical damage occurs. Therefore,
The rotating shafts, bearing stands, etc. of these rotating machines are provided with vibration detection devices that detect this vibration, and the vibrations of the rotating shafts, etc. are constantly monitored.

Conventionally, a vibration detecting device as shown in FIG. 5 has been used.

That is, a vibration detector 1o for detecting mechanical vibration is attached to a rotating shaft, a bearing stand, etc. of a rotating machine (not shown). The vibration detector 1o has a built-in signal converter (not shown) for converting mechanical vibrations into electrical signals, and the mechanical vibrations are usually extracted as an alternating current electrical signal e]. This AC signal e1 is sent to a rectification/smoothing circuit 11 consisting of a rectifier, a capacitor, etc., and is converted into a DC signal e2 from which ripple components have been removed. This DC signal e2 is sent to the amplifier 12, where it is amplified into a DC signal e8 in the range of 0 to 4 vdc, which is the nJ constant range width of the measuring instrument (not shown). This DC 1. ; For No. e8, a zero value is transferred to make the reading, indication, etc. of the 1iiJ mark i'1lll meter accurate.

In other words, the entire measurement range 0 to 4vdc is 1vdc.
The output signal e9 is sent to the adding circuit 13 to be raised, and is made into a unified reference signal with the measurement range of the output signal e9 being 1 to 5 VDC.

When the vibration is small or gentle, such a vibration detection device detects the vibration of the rotating shaft as it is as a unified reference signal. To explain this relationship with reference to FIGS. 6(a) to 6(e), the AC signal e1 of the vibration detector 10 increases as the amount of vibration increases (FIG. 6(a)
)). The ripple component of this AC signal is removed by the rectifier/smoothing circuit 11 (FIG. 6(b)), and the signal is converted into a DC signal e2 (FIG. 6(C)). This DC signal e2 is sent to the amplifier 1
2 is amplified to a range of 0 to 4 vdc (Figure 6 (d))
, is converted into a unified reference signal of 1 to 5 VDC by the adding circuit 13, and the vibration of the rotating shaft etc. is measured by the measuring device (see Fig. 6 (e).
)).

(Problem to be Solved by the Invention) By the way, in such a vibration detection device, when the vibration of the rotating shaft etc. reaches a large value, the mechanical vibration is not accurately converted into an electrical signal due to the characteristics of the vibration detector 10 etc. ,amplifier,
There is a problem in that an error occurs in the output signal taken out through the adder.

That is, in FIG. 7(a), when the amount of vibration of the rotating shaft detected by the vibration detector 10 becomes a value equal to or greater than po, the ideal AC signal e1 for the amount of vibration actually has a characteristic like eal, and the ideal This will cause an error between the two.

This error occurs when a sensor that detects mechanical vibrations, for example, when a contact piece drives a permanent magnet or coil and induces alternating current power in the coil, the vibration of the contact piece cannot accurately follow the permanent magnet or coil. be.

This error signal is transmitted through the rectifier/smoothing circuit (Fig. 7(b)), the DC signal (Fig. 7(c)), and the amplified DC signal (Fig. 7(c)).
(D)) and the unified reference signal (FIG. 7(E)), the vibrations of the rotating shaft of the rotating machine cannot be measured accurately.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to obtain a vibration detector capable of detecting vibrations of a rotating shaft of a rotating machine without error.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a vibration detector that detects vibrations of a rotating shaft or a bearing stand of a rotating machine, converts the vibrations into electrical signals, and extracts the vibrations, and an error detector that detects an error when the electrical signal has an error with the mechanical vibration and generates an error No. 16; and a correction that is activated by the error signal of this error detector to correct the electrical signal. The apparatus includes a correction amplifier that generates a signal, and an addition circuit that adds the correction signal of the correction amplifier and the electric signal to generate a unified reference signal.

(Function) When a rotating machine etc. rotates, its rotating shaft rotates while vibrating. Furthermore, this vibration of the rotating shaft is also transmitted to the bearing stand. These vibrations are detected by a vibration detector, converted into electrical signals, and then measured by a measuring device.

In measuring such mechanical vibrations, if the mechanical vibrations detected by the vibration detector become large, the mechanical vibrations may not be properly converted into electrical signals, resulting in errors. This error is detected by an error detector, and its output signal, the error signal, activates a correction amplifier. Activation of the correction amplifier generates a correction signal, which corrects the electrical signal.

This corrected signal allows accurate measurement of mechanical vibrations.

(Embodiment) An embodiment of the vibration detection device of the present invention will be described below with reference to the accompanying drawings. The vibration detection device of the present invention and FIGS. 5 to 7
The same parts as those of the vibration detection device shown in the figures will be explained using the same reference numerals, and detailed explanation thereof will be omitted.

In the vibration detection device shown in FIG. 1, the detected AC signal e1 from the vibration detector 10 is passed through a rectification/smoothing circuit 11 to an amplifier 21 of a linearity correction device 20, a correction amplifier 22, a comparator 23 which is an error detector, etc. input terminal 21 of
a + sent to 22a and 23a.

When the amplifier 21 receives the DC signal e2, this DC signal e
2 is amplified to e4 and sent to the first adder 24. The DC signal e6 from the first adder 24 is sent to the second adder 25, where the measurement range is adjusted to 1 to 5 vdc and made into a unified reference signal.

The correction amplifier 22 stores a correction signal e5 determined from the characteristics of the vibration detector 10 used. This correction signal e5 is a signal that is small when the amount of vibration of the rotating machine is small, and increases for a while when it becomes large. - In boat fishing, the signal is linear as shown by e5 in FIG. 2(d), but there is also a signal that increases in a curved manner. A switch 26 operated by the output signal of the comparator 23 is connected to the output terminal of the compensation amplifier 22, and when the switch 25 is closed, the compensation amplifier 2
The correction signal from 2 is sent to a first adder 24.

The comparator 23 is the DC signal e2 of the rectifier/smoothing circuit 11.
When received, it is compared with the setting value e3 of the setting device and the DC signal e
2 becomes larger than the set value e3, comparator 2
3 generates an output signal to close the switch 25.

This set value e3 is experimentally determined from a value that causes an error determined from the characteristics of the vibration detector 10.

When the output signal is generated from the comparator 23, the switch 25 is closed and the correction signal from the correction amplifier 22 is sent to the first adder 24. first adder 2
4, the DC signal e4 and the correction signal e5 are added,
The mechanical vibrations are corrected into a qualified DC signal e6 and sent to the second adder 25. In this second adder 25, the measurement range is increased by 1 Vdc to obtain a unified reference signal e7.

These relationships will be explained with reference to FIG. That is, when the amount of vibration of the rotating machine increases as shown in FIG. 2(a), the AC output signal of the AC 1u number e1 detected by the vibration detector 10 also increases. When the amount of vibration exceeds the po point, for example, the mechanical vibration detected by the vibration detector 10 is not accurately converted into an electric signal, that is, an error signal ef
(Figure 2(a)). The AC signal e1 including this error signal ef is rectified, and the ripple is removed from the DC signal e.
2 to the correction amplifier 22 and comparator 23. When the comparator 23 receives the error signal ef, it is compared with a set value e3 and an output signal is generated. When this output signal is generated, the switch 26 is closed, and the correction signal e5 of the correction amplifier 22 is sent to the first adder 24.

When the first adder 24 receives the correction signal e5, this correction signal e5 is added to the amplified signal e4, and this added signal e6 is made into a DC signal with linearity proportional to the mechanical vibration (second Figure (e)). This DC signal e6 is sent to the second adder 25 and measured by a measuring device as a unified reference signal e7 (FIG. 2(f)). In this way, vibrations of the rotating shaft and bearing stand of the rotating machine can be accurately detected.

FIG. 3 shows another embodiment of the vibration detector shown in FIG. It is basically the same as the vibration detector shown in FIG.

However, if the vibration detector that detects the vibration of the rotating machine is different, the correction amplifier 3 is used to match the vibration detector.
2 is provided with an adjuster 32m, and the comparator 33 is provided with a set value adjuster 33m, so that the correction signal of the correction amplifier 32 and the set value of the comparator 33 can be adjusted.

FIG. 4 is an explanatory diagram showing a method for adjusting the correction characteristic of the correction amplifier 32 in FIG. 3 (FIG. 4(a)) and a method for adjusting the set value of the comparator 33 (FIG. 4(b)).

In this way, even if different vibration detectors are used,
Mechanical vibrations can be detected accurately without errors by adjusting each time.

〔Effect of the invention〕

According to the vibration detection device of the present invention, the vibration detector is provided with an error detector and a correction amplifier, and when the error detector is activated, the correction amplifier corrects the conversion error signal of the vibration detector. can be determined as an accurate signal.

In addition, when the error detector converts mechanical vibration into an electrical signal, it detects and corrects the part where the conversion characteristics deteriorate, so the mechanical vibration does not have an adverse effect on the small vibration part that is proportional to the electrical signal. There is no.

[Brief explanation of the drawing]

FIG. 1 is an electrical block diagram showing the main parts of the vibration detection device of the present invention, FIG. 2 is an explanatory diagram explaining the operating characteristics of the vibration detection device shown in FIG. 1, and FIG. An electrical block diagram showing another modification of the vibration detecting device shown in the figure, FIG. 4 is an explanatory diagram explaining the operating characteristics of the vibration detecting device shown in FIG. 3, and FIG. Electrical block diagrams of the vibration detection device, FIGS. 6 and 7, are explanatory diagrams for explaining the operating characteristics of the vibration detection device shown in FIG. 5. 10... Vibration detector, 11... Rectifier/smoothing circuit, 1
2... Amplifier, 13... Adder, 20... Linearity correction device, 21... Amplifier, 22... Correction amplifier,
23... Comparator, 24... First adder, 25
...Second adder, 26...Switch, 32...Correction amplifier, 32m...Adjuster, 33...Comparator, 33m...Adjustment setting device.

Claims (1)

[Claims] A vibration detector detects the vibration of the rotating shaft or bearing stand of a rotating machine, converts this vibration into an electrical signal, and extracts it. There is an error between the electrical signal converted by this vibration detector and the mechanical vibration. an error detector that detects this error and generates an error signal when the error occurs; a correction amplifier that is activated by the error signal of the error detector and generates a correction signal that corrects the electric signal; and a correction signal of the correction amplifier. A vibration detection device comprising: an addition circuit that adds the electrical signals and generates a unified reference signal.