JPH0626848A - Eccentricity measuring apparatus - Google Patents

Abstract

PURPOSE:To prevent the output of a higher eccentricity and to avoid the state, wherein a rotary body cannot be started, by providing a means, which detects the deviation of the center of a rotary shaft and resets the hold of the maximum peak-to-peak amplitude value when the deviation is detected. CONSTITUTION:A deviation detecting circuit 10 comprises a differentiating circuit, an operation amplifier 106, an absolute-value amplifier circuit 103, a comparator 104 and a constant-time generating circuit 105. Under the state, wherein the eccentricity of a rotary shaft 1 is measured, a reset signal is applied into a positive-side peak-hold circuit 41 and a hold circuit 43 when the deviation of the center of the rotary shaft 1 is generated and detected with the deviation detecting circuit 10. The maximum peak-to-peak amplitude value of the eccentricity is reset. Sampling operation is started from the initial value of the eccentricity. Therefore, not only the output of the heigher eccentricity to the outside can be prevented, but also the state, wherein a rotary body such as a turbine cannot be started because of the output of the higher eccentricity caused by the devaition of the center of the rotary shaft 1, can be avoided. Thus, the normal monitoring of the rotary body can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentricity measuring device for measuring the eccentricity of a rotary shaft of a rotating body such as a turbine generator.

[0002]

2. Description of the Related Art A turbine-generator rotates a turbine with steam, and the rotation of the turbine rotates the generator to generate electricity. In the previous stage of rotating the turbine generator and increasing the rotation speed of the generator to the rated rotation speed, the bending of the rotating shaft of the turbine, that is, the eccentricity amount is measured, and the turning state is maintained until the eccentricity amount reaches a certain value. The turbine rotational speed is continuously increased after the eccentric amount reaches a predetermined value. Here, the turning state is
To reduce the amount of eccentricity of the turbine rotating shaft, 2
Rotating the rotating shaft of the turbine in 3 rotations.

Conventionally, a non-contact type displacement meter is used to measure the eccentricity of the rotating shaft of the turbine, and the maximum return amplitude value (PEAK TO PEAK) of the eccentricity, which is the detection output, is captured to determine the eccentricity of the rotating shaft. An eccentricity measuring device for determining the quantity is used. FIG. 5 is a block diagram showing an example of this kind of conventional eccentricity measuring device, and FIG. 4 is a time chart for explaining this operation, which will be described below.

A displacement meter 2 is disposed in a non-contact state in the vicinity of the surface of the turbine rotating shaft 1, and a displacement detection signal a detected by the displacement meter 2 is impedance-converted by a buffer 3 and then an eccentric amount is obtained. Maximum return amplitude value calculation circuit 4
The maximum return amplitude value of the eccentricity amount is detected and calculated from the amplitude value of the detection signal. Maximum return amplitude value detection arithmetic circuit 4
Is a positive-side peak hold circuit 41 and a differential amplifier circuit 42.
And a maximum return amplitude value hold circuit 43 for the amount of eccentricity.

The positive side peak hold circuit 41 is an operational amplifier 41a, a diode 41b, and a signal passing switch 41.
It is composed of c and a capacitor 41d, and holds the positive peak value of the displacement detection signal. The differential amplifier circuit 42 includes operational amplifiers 42a and 42b and resistors 42c, 42d and 42.
e, 42f, and a signal obtained by inverting the displacement detection signal and the positive peak hold value are added. Hold circuit 43
Is composed of an operational amplifier 43a, a diode 43b, a signal passing switch 43c, and a capacitor 43d, and outputs a maximum rebound amplitude value hold signal b of the eccentric amount, which is an output signal of the differential amplifier circuit 42. The hold circuit 5 including the operational amplifier 51, the resistor 52, the signal passing switch 53, and the capacitor 54 holds the hold value of the maximum return amplitude value hold circuit 43.

The output of the hold circuit 5 is input to the zero-span adjusting circuit 6 via the operational amplifier 8 and zero-span adjusted so as to obtain a predetermined output signal. V / I conversion circuit 7
Converts the output signal whose zero span is adjusted by the zero span adjustment circuit 6 into an operation signal of an external instrument.

Further, the reset signals f and f1 output from the reset and hold clock generation circuit 9 give an ON command to the signal passing switches 41c and 43c, and the positive side peak hold circuit 41 of the eccentricity amount and the eccentricity amount. The maximum hold amplitude value hold circuit 43 resets the value held for a fixed time, and the hold signal g of the reset and hold clock generation circuit 9 gives an ON command to the signal passing switch 53 to change the eccentricity amount. The value held by the maximum return amplitude value hold circuit 43 is held for a certain period of time. The reset-and-hold clock generation circuit 9 is configured to repeat the generation of the reset signals f and f1 and the hold signal g at regular intervals as described above.

The reset cycle in this case is set so that the maximum return amplitude of the eccentricity always occurs twice with respect to the signal waveform at the time of turning the turbine rotary shaft 1.
This is because the reset pulse is not synchronized with the rotation speed, so that the maximum value is always detected and calculated even when the reset pulse is reset in the middle of the signal waveform.

In the eccentricity measuring device configured as described above, during turning of the rotating shaft, the displacement detection signal a from the displacement gauge 2 has a repetitive waveform that is approximately a sine wave, as shown in FIG. There is. This sine wave signal a is supplied to the buffer 3
After the impedance conversion is performed by, the positive side peak hold circuit 41 holds the positive side peak value.
After that, a signal obtained by inverting the input signal in the differential amplifier circuit 42,
That is, the peak value on the negative side is added to obtain the maximum return amplitude value b of the eccentricity amount, and this maximum return amplitude value b is held by the maximum eccentricity amount return amplitude value hold circuit 43 arranged in the next stage. To do.

By the way, the displacement meter 2 is mounted with a certain gap with respect to the rotary shaft 1 in the initial state, but the center of the rotary shaft 1 may deviate, which causes the following problems. May occur.

That is, for example, a pad bearing that rotatably supports the rotary shaft 1 has an elliptical inner peripheral surface, so that the center of the rotary shaft 1 may be displaced.
When the center of the rotary shaft 1 shifts, the gap between the rotary shaft 1 and the displacement meter 2 changes stepwise, and the center of the detection signal of the displacement meter 2 also changes stepwise as shown in FIG. It should be noted that such a change does not pose any problem as the movement before the rise of the rotation of the turbine.

However, the maximum return amplitude value detection circuit 4 catches the detection signal of the displacement meter 2 which has changed stepwise as the eccentric amount of the rotary shaft 1, and the reset and hold generation circuit at the timing shown in FIG. 6C. The eccentricity amount output signal h0 higher than the actual eccentricity amount is output from the hold circuit 5 for a certain period until the next cycle in which the reset signal f1 output from 9 resets. As a result, the turbine cannot be started.

[0013]

As described above, in the conventional eccentricity measuring device, when the center of the rotating shaft 1 is displaced and the gap between the rotating shaft 1 and the displacement gauge 2 changes stepwise, the turbine is originally Although there is no problem in the movement in the previous stage of the rotation increase, this is regarded as a kind of eccentricity of the rotating shaft, so that the turbine is not started.

Therefore, according to the present invention, it is possible to prevent a high eccentricity amount from being output to the outside, and avoid an eccentricity amount measuring device capable of avoiding a state in which the rotor cannot be started due to a high eccentricity amount output due to a deviation of the center of the rotating shaft. The purpose is to provide.

[0015]

In order to achieve the above object, the invention according to claim 1 holds a maximum rebound amplitude value of an eccentric amount of a rotary shaft of a rotating body and makes it possible to measure the value. In addition, a means for detecting the deviation of the center of the rotation axis and resetting the hold of the maximum return amplitude value when the deviation is detected is provided.

The invention according to claim 2 further comprises a plurality of hold circuits for respectively holding the maximum return amplitude value, hold timing means for applying sample hold timings to the respective hold circuits at different timings, Low hold value selecting means for selecting a lower hold value among the hold values output from each hold circuit.

[0017]

According to the invention corresponding to claim 1, since the means is provided, it is possible to prevent the output of a high eccentricity amount to the outside, and to increase the eccentricity amount due to the deviation of the center of the rotating shaft. It is possible to avoid the situation where the output cannot start the rotating body.

According to the second aspect of the invention, the plurality of hold circuits for respectively holding the maximum return amplitude value start the hold at different timings by the hold timing means. Therefore, the eccentric amount of the rotary shaft is sampled and held by the plurality of hold circuits at different timings. Then, a low hold value is always selected by the low hold value selection means. Therefore, if the eccentricity amount is monitored by using the hold value selected by the low hold value selecting means, it is possible to prevent the eccentricity amount that is higher than the outside from being output, and increase the eccentricity amount due to the deviation of the center of the rotating shaft. It is possible to avoid the state where the rotating body cannot be started by the output of.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first eccentricity measuring device according to the present invention.
2 is a block diagram showing a schematic configuration of the embodiment of FIG. 2, and FIG. 2 is a time chart for explaining this operation. In addition,
Since the configuration of the present embodiment is similar in part to the configuration of the eccentricity measuring device shown in FIG. 5, parts having the same function are designated by the same reference numerals to avoid redundant description.

The deviation detecting circuit 10 is a differentiating circuit, operational amplifier 106, absolute value amplifying circuit 103, comparator circuit 1
04, a constant time generation circuit 105. The differentiating circuit consists of a capacitor 101 and a resistor 102,
The detection signal a detected in (1) is input through the operational amplifier 3, the signal is differentiated, and a whisker-shaped differential signal is output.
The operational amplifier 106 amplifies the differential signal from the differentiating circuit, inputs the amplified shift detection signal c into the absolute value amplifying circuit 103, and extracts it as a positive side signal, that is, the absolute value amplified signal d. Comparator circuit 104
Inputs the absolute value amplified signal d, compares it with a predetermined set voltage, and outputs a deviation signal. Generation circuit 1 for a fixed time
Reference numeral 05 outputs a reset signal e to secure the deviation signal from the comparator circuit 104 for a fixed time.

Next, the operation of the embodiment configured as described above will be described with reference to the time chart of FIG.
The amount of eccentricity of the rotary shaft 1 is detected by the displacement meter 2, and the detection signal a is input to the positive side peak hold circuit 41 of the maximum eccentricity return amplitude value detection arithmetic circuit 4. The positive peak hold circuit 41 holds the positive maximum value.
Then, in the next differential amplifier circuit 42, the maximum value on the positive side held by the positive side peak hold circuit 41 and the detection signal a
Of the eccentricity amount is detected and calculated, and thereafter, the maximum recovery amplitude value of the eccentricity amount is held by the maximum recovery amplitude value hold circuit 43. is there.

In this state, when the center of the rotary shaft 1 is deviated, a differential circuit shown by c, that is, a deviation detection signal is output from the differentiating circuit composed of the capacitor 101 and the resistor 102, which is passed through the operational amplifier 106. And is amplified by the absolute value amplifier circuit 103, and an absolute value amplified signal (a signal on the positive side) d is obtained. Then, the comparator circuit 104
, The absolute value amplified signal d is compared with a predetermined set value (voltage), and when there is a deviation between the two, the generation circuit 10
5, a reset signal e is obtained, and this reset signal e
Are supplied to the reset and hold clock generation circuit 9. When the reset signal e is applied to the reset and hold clock generation circuit 9, the reset signal f is applied to the positive peak hold circuit 41 and the hold circuit 43.

From the above, the conventional high eccentricity amount generated when the center of the rotary shaft 1 is displaced is reset, and the eccentricity amount sampling operation is started from the initial value of the eccentricity amount. In this case, as for the eccentric output to the outside, the output signal g is output from the reset and hold clock generation circuit 9 to the hold circuit 5, so the hold circuit 5
Outputs an output signal h having the maximum return amplitude value of the eccentricity.

In FIG. 2, f1 is a reset signal given from the reset and hold clock generation circuit 9 to the positive peak hold circuit 41 and the hold circuit 43 in the standard state.

According to the above-described embodiment, when the deviation of the center of the rotary shaft 1 occurs while the eccentricity of the rotary shaft 1 is being measured, when the deviation detection circuit 10 detects the deviation, the positive side is detected. A reset signal is given to the peak hold circuit 41 and the hold circuit 43, the maximum return amplitude value of the eccentricity amount is reset, and the sampling operation is started from the initial value of the eccentricity amount. Therefore, a high eccentricity amount is output to the outside. Not only can this be prevented, but a state in which the rotating body such as the turbine cannot be started due to the increased eccentricity amount due to the deviation of the center of the rotating shaft 1 can be avoided, and the normal rotating body can be monitored.

Further, since the deviation detection circuit 10 is constructed so as to operate by the input signal from the displacement meter 2, it is not necessary to take in a new signal from the outside, so that the equipment can be simplified and the equipment cost can be reduced. It also contributes to the reduction of Next, a second embodiment of the eccentricity measuring device according to the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a functional block diagram of the eccentricity amount measuring device according to the second embodiment. Note that FIG.
The parts having the same functions as those of the eccentricity measuring device shown in are given the same reference numerals.

In the eccentricity amount measuring apparatus of this embodiment, hold circuits 5A and 5B are arranged in parallel with the output stage of the maximum return amplitude value hold circuit 43, and these hold circuits 5 are arranged.
A low hold value selection circuit 61 that always selects a lower hold value is provided at the output stages of A and 5B. The hold value selected by the low hold value selection circuit 61 is input to the zero span adjustment circuit 6.

A reset-and-hold clock generation circuit 60 for sampling and holding and resetting the maximum return amplitude value of the input signal at a constant cycle is provided. The reset and hold clock generation circuit 60 alternately outputs a reset signal at a constant cycle to the switch 41c of the positive peak hold circuit 41 and the switch 43c of the maximum recovery amplitude value hold circuit 43, and both hold circuits. The respective hold signals are output to the 5A and 5B switches 53A and 53B at a constant cycle so as to hold the maximum return amplitude value at different timings. Next, the operation of this embodiment configured as described above will be described.

A sinusoidal displacement signal indicating the amount of eccentricity of the turbine rotary shaft 1 detected by the displacement meter 2 is input to the positive side peak hold circuit 41, and the positive side peak value of the input signal is held. Then, the signal obtained by inverting the displacement signal and the positive peak value held by the positive peak hold circuit 41 in advance are added by the differential amplifier 42 to detect the maximum decentering amplitude value of the eccentric amount. The maximum recovery amplitude value obtained by the differential amplifier 42 is held by the maximum recovery amplitude value hold circuit 43, and the maximum recovery amplitude value is held by each hold circuit 5.
The signals A and 5B are held at the timing of the hold signal from the reset and hold clock generation circuit 60.

Here, if a gap shift occurs between the turbine rotating shaft 1 and the displacement meter 2, and the displacement detection signal from the displacement meter 2 changes stepwise as shown in FIG. 4 (a), The hold signal of the maximum return amplitude value held by the maximum return amplitude value hold circuit 43 becomes large as shown in FIG.

On the other hand, the hold signals for the hold circuits 5A and 5B are given at different timings, as shown in FIGS. For example, when the timings at which the hold signal is applied to the hold circuit 5A overlaps when the gap shift occurs as shown in FIG. 4D, the hold circuit 5 as shown in FIG.
A holds the higher maximum return amplitude value and outputs the higher maximum return amplitude value until the next reset.

At this time, the other hold circuit 5B holds the maximum return amplitude value of the eccentricity amount by the hold signal before the gap deviation occurs, and outputs the maximum return amplitude value.

The low hold value selection circuit 61 selects the smaller one of the hold voltages appearing at the outputs of the two hold circuits 5A and 5B and outputs it to the zero span adjustment circuit 6 in the subsequent stage.

As a result, even if one of the hold circuits 5A holds a higher maximum return amplitude value when a gab shift occurs, the hold value is not selected and the lower hold value is always output. Becomes

As described above, according to this embodiment, the eccentricity of the turbine rotary shaft 1 is set by the two hold circuits 5A and 5B.
Since the sample and hold is performed at different timings and the lower hold value is always selected, the high output is not output to the outside even if a high eccentricity is held due to a gab shift and the normal eccentricity is maintained. Can be output. Therefore, it is possible to avoid a state in which the rotating body cannot be started with an output with a high eccentricity. The eccentricity measuring device may be configured by combining the first embodiment and the second embodiment.

[0037]

According to the present invention, it is possible to prevent a high eccentricity amount from being output to the outside, and to avoid a state in which the rotating body cannot be started by an output with a high eccentricity amount due to the deviation of the center of the rotating shaft. An eccentricity measuring device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an eccentricity measuring device according to the present invention.

FIG. 2 is a time chart for explaining the operation of the eccentricity measuring device shown in FIG.

FIG. 3 is a block diagram showing a second embodiment of the eccentricity measuring device according to the present invention.

FIG. 4 is a time chart for explaining the operation of the eccentricity measurement device shown in FIG.

FIG. 5 is a block diagram showing an example of a conventional eccentricity measuring device.

FIG. 6 is a time chart for explaining problems of the eccentricity measuring device of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotation axis, 2 ... Non-contact type displacement meter, 4 ... Maximum return amplitude value detection arithmetic circuit of eccentricity, 5 ... Hold circuit, 6 ... Zero span adjustment circuit, 7 ... V / I conversion circuit, 9 ... Reset and hold Clock generation circuit, 10 ... Deviation detection circuit.

Claims (2)

[Claims] 1. A device in which a maximum rebound amplitude value of an eccentricity amount of a rotary shaft of a rotating body is held and the value can be measured, the shift of the center of the rotary shaft is detected, and the shift is detected. An eccentricity measuring device comprising means for resetting the hold of the maximum return amplitude value when 2. An eccentricity measuring device for detecting an eccentricity of a rotary shaft of a rotating body by an eccentricity detector and detecting a maximum return amplitude value of the eccentricity detected by the eccentricity detector at a predetermined cycle. The plurality of hold circuits that respectively hold the maximum return amplitude value, the hold timing means that gives the sample hold timing to the respective hold circuits at different timings, and the lower hold value output from each of the hold circuits An eccentricity amount measuring device comprising: a low hold value selecting means for selecting one of the hold values.