JP2980465B2 - Eccentricity measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentricity measuring apparatus for measuring the eccentricity of an axle of a turbine generator. The present invention relates to an eccentricity measuring apparatus capable of measuring the eccentricity.

[0002]

2. Description of the Related Art In general, in an industrial power generation system and a private power generation system, a device for monitoring the amount of eccentricity of a turbine axle is used.

[0003] That is, a turbine generator obtains electricity by rotating a turbine with steam and turning the generator with the rotation of the turbine. In the stage before rotating the turbine generator to increase the rated speed, the bending of the turbine axle, that is, the amount of eccentricity is measured, and the eccentricity is turned until the eccentricity reaches a certain value. The state where the axle is rotated to reduce the bending of the axle) is continued, and the rotation is increased after the eccentricity reaches a certain value. In this case, a non-contact displacement meter is used to measure the eccentricity, and the output of the displacement meter, PEAK TO PEAK, is captured to determine the eccentricity of the axle. FIG. 3 is a block diagram showing a configuration example of this type of conventional eccentricity measuring device.

In FIG. 3, an output signal (eccentricity) from an eccentricity detector 22 mounted opposite a turbine axle 21 is received by a buffer 23 and subjected to impedance conversion, and then a positive signal of a PEAK TO PEAK detection operation circuit 24 is obtained. The positive peak hold value of the eccentricity of the turbine axle 21 is held by the side peak value hold circuit 24A.

Next, the differential amplifier 24B of the PEAK TO PEAK detection operation circuit 24 adds the inverted signal of the input signal and the previously held positive peak value,
The PEAK TO PEAK signal of the input signal is
The EAK TO PEAK is held by the hold circuit 24C.

[0006] This peak hold value is supplied to the PEAK T
The reset / hold clock generation circuit 26 for turning on the switch at regular intervals to hold the O PEAK value is configured to repeat reset and hold value output at regular intervals.

In this case, the reset period is determined by a fixed time according to the turning period of the turbine axle 21, and this time is the PEAK of the signal waveform at the time of turning.
It is set so that TOPEAK always comes twice. This is because the reset pulse is not synchronized with the rotation speed,
Even if reset is performed in the middle of the signal waveform, PEA
It is considered that K TO PEAK is detected and calculated.

Next, the zero-span adjusting circuit 27
The hold value of the hold circuit 25 is zero-span-adjusted so as to be a predetermined output signal.
Converts the zero-span adjusted signal into an operation signal of an external instrument.

Incidentally, in such an eccentricity measuring apparatus, the eccentricity detector 2 during turning of the turbine axle 21 is used.
The output signal from 2 has a repetitive waveform substantially similar to a sine wave.

That is, after the input signal from the eccentricity detector 22 is received by the buffer 23 and subjected to impedance conversion,
The positive peak value is held by the positive peak hold circuit 24A. Next, by adding the inverted signal of the input signal, that is, the negative peak value in the differential amplifier 24B, the PEAK TO PEAK value of the input signal is added to the next stage PEAK.
The TO PEAK hold circuit 24C holds the signal.

However, the eccentricity detector 22 is mounted with a certain gap from the turbine axle 21. However, when the mounting gap changes stepwise and the center of the eccentricity shifts, the eccentricity detection is performed. The center of the output signal of the detector 22 also changes stepwise.

That is, the center of the sinusoidal eccentricity output changes stepwise, and the PEAK TOPEAK detection / calculation circuit 24 catches this stepwise change, and is higher than the actual eccentricity until the next cycle in which resetting is performed. There is a problem in that the eccentricity amount is output.

In this case, it is considered correct for the eccentricity measuring device to detect this stepwise change because it is a kind of eccentricity, but the deviation of the center of the turbine axle 21 is the movement before the rotation rise. Since there is no problem at all, a state where the output is higher for a certain period of time and the turbine cannot be started is very problematic.

[0014]

As described above, in the conventional eccentricity measuring apparatus, when the mounting gap of the eccentricity detector changes stepwise and the center of the eccentricity of the axle is shifted, However, there has been a problem that the amount of eccentricity of the axle cannot be accurately measured.

An object of the present invention is to provide an extremely reliable eccentricity measuring device capable of measuring the eccentricity accurately and in a minimum time even when the center of the eccentricity of the axle is shifted. It is in.

[0016]

According to the present invention, there is provided an eccentricity measuring apparatus for measuring the amount of eccentricity of an axle to be monitored. Eccentricity detecting means for detecting the amount of eccentricity, and maximum eccentricity based on the amount of eccentricity detected by the eccentricity detecting means.
Calculates the amplitude value and calculates the amplitude at different times.
First and second eccentric weight maximum amplitude value detecting operation hold means for sampling and holding every fixed cycle, each eccentricity top
The first and second holding means for holding the hold value of the large amplitude value detection calculation holding means at regular intervals, and the sample and hold cycle of each of the eccentric amount maximum amplitude value detection calculation holding means corresponds to the rotation speed of the axle. It operates based on the amount of eccentricity detected by the eccentricity detecting means so as to synchronize, and generates a sample hold signal of each eccentricity amount maximum amplitude value calculation operation holding means and generates a hold signal of each holding means. A sample and hold signal generation means, and a low hold value selection means for selecting the lower one of the hold values of the two eccentric amount maximum amplitude value detection calculation hold means and outputting the selected hold value to the outside; means, sample-and-hold period is quite the opposite in each of eccentricity maximum amplitude value detecting operation hold means To generate a sample-and-hold signal to operate at timing, each of the eccentricity maximum amplitude
The hold signal is generated so that the value detection arithmetic holding means holds immediately before sampling.

Here, in particular, as the sample-and-hold signal generating means, a first flip-flop circuit which receives the amount of eccentricity detected by the eccentricity detecting means and operates at a zero-cross point once per rotation of the axle; A second flip-flop circuit which receives an output signal from the first flip-flop circuit and operates once every two rotations of the axle, and a second flip-flop circuit for delaying the output signal of the second flip-flop circuit. First and second filters and the first
And the logical product of the output signal of the second filter and the output signal of the second flip-flop circuit, respectively, and outputs the result as a sample-and-hold signal of the first and second eccentricity maximum amplitude value detection operation holding means. And a second AND circuit, and an exclusive OR of an output signal of each of the first and second AND circuits and an output signal of the first and second filters is provided. And a first and a second exclusive OR circuit for outputting as a hold signal.

[0018]

Therefore, in the eccentricity measuring device of the present invention,
A certain constant eccentricity of the axle to be monitored is different from each other by two eccentricity maximum amplitude value detection calculation holding means.
Sampling and holding are performed at predetermined timing intervals, that is , at intervals opposite to each other.
By selecting and outputting the correct hold value, the mounting gap of the eccentricity detection means changes stepwise,
Even if the axle shift occurs and the higher eccentricity is held,
The higher output is not output to the outside, and the normal eccentricity can be continuously output.

Further, the sample signal of the two eccentricity maximum amplitude value detection arithmetic holding means and the hold signal of the two hold means are generated based on the eccentricity which is the output signal of the eccentricity detecting means. The eccentricity can be measured in synchronization with the rotation speed of the axle, and the eccentricity can be measured and the eccentricity can be output in a minimum time. As described above , even when the center of the eccentricity of the axle is shifted, the eccentricity can be measured accurately and in a minimum time.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the overall configuration of an eccentricity measuring apparatus according to the present invention. That is, as shown in FIG. 1, the eccentricity measuring device of the present embodiment includes an eccentricity detector 2 attached to a turbine axle 1 to be monitored with a certain gap, a buffer 3, First and second positive side peak value hold circuits 4A and 5A, first and second
Differential amplifiers 4B and 5B, and first and second eccentricity maximum amplitudes
Value (hereinafter referred to as PP) hold circuits 4C and 5C, first and second PP detection arithmetic hold circuits 4 and 5
, First and second hold circuits 6, 7, a low hold value selection circuit 8, a zero-span adjustment circuit 9, a V / I conversion circuit 10, and a reset / hold clock generation circuit serving as a sample / hold signal generation means. 11 is comprised. Here, the eccentricity detector 2 detects the amount of eccentricity of the turbine axle 1. The buffer 3 converts the eccentricity signal a detected by the eccentricity detector 2 into impedance and outputs the converted signal. On the other hand, the first and second positive side peak value hold circuits 4A and 5A receive the output signal of the buffer 3 and hold the positive side peak hold value.

The first and second differential amplifiers 4B and 5B
Are first and second positive side peak value hold circuits 4A and 5A
Is added to the positive-side peak value held earlier to calculate PP. Furthermore, the first and second PP hold circuits 4C and 5
C samples and holds PP of the first and second differential amplifiers 4B and 5B.

On the other hand, the first and second hold circuits 6, 7
Is to hold the hold values l and m of the first and second PP hold circuits 4C and 5C for an external output signal at regular intervals. Further, the low hold value selection circuit 8 selects and outputs the lower one of the hold values n and p of the first and second hold circuits 6 and 7. Further, the zero-span adjustment circuit 9
The zero-span adjustment is performed so that the output value q of the low hold value selection circuit 8 becomes a predetermined output signal. Further, the V / I conversion circuit 10 converts an output signal of the zero-span adjustment circuit 9 into an operation signal of an external instrument and outputs the operation signal.

On the other hand, the reset / hold clock generation circuit 11 operates on the basis of the output signal a of the eccentricity detector 2, and the sample and hold period of the first and second PP detection operation hold circuits 4 and 5 is changed. The first and second positive peak value hold circuits 4A, 4A, of the first and second PP detection calculation hold circuits 4, 5 are synchronized with the rotation speed of the turbine axle 1.
5A and first and second PP hold circuits 4C and 5C
And the hold signals of the first and second hold circuits 6 and 7, ie, the signals f and k for turning on / off the first and second signal passing switches 6A and 7A. Is generated.

Here, in the reset / hold clock generation circuit 11, the sample hold period differs between the first and second PP detection operation hold circuits 4 and 5.
The sample and hold signal is generated so as to operate at predetermined timings at predetermined intervals, that is, at completely opposite timings, and the first and second PP detection arithmetic hold circuits 4,
First and second so that 5 holds just before sampling
The hold signals of the hold circuits 6 and 7 are generated.

That is, as shown in FIG. 1, the reset / hold clock generation circuit 11 receives the output signal of the buffer 3 as an input, and operates the first flip-flop which operates at a zero-crossing point once per rotation of the turbine axle 1. Circuit 11A
And a second flip-flop circuit 11B which receives an output signal from the first flip-flop circuit 11A and operates at a cycle of two rotations of the turbine axle 1, and a second flip-flop circuit 11B. First and second filters 11C and 11D for respectively delaying output signals;
The logical product of the output signals of the first and second filters 11C and 11D and the output signal of the second flip-flop circuit 11B is respectively obtained, and the first and second positive peak value hold circuits 4A and 5A and First and second AND circuits 11E and 11F outputting as sample and hold signals of the first and second PP hold circuits 4C and 5C,
The exclusive OR of the output signals of the first and second AND circuits 11E and 11F and the output signals of the first and second filters 11C and 11D is calculated.
7 and a first exclusive OR circuit 11G and a second exclusive OR circuit 11H which output as a hold signal. Next, the operation of the eccentricity measuring apparatus according to the present embodiment configured as described above will be described with reference to a time chart shown in FIG.

In FIG. 1, the first and second positive peak hold circuits 4A and 5A in the first and second PP detection arithmetic hold circuits 4 and 5 output the signal a from the eccentricity detector 2 in the first and second positive peak hold circuits 4A and 5A. As a result, the peak value on the positive side is held. Next, in the first and second differential amplifiers 4B and 5B, the inverted signals of the output signals from the first and second positive-side peak hold circuits 4A and 5A and the positive-side peak value previously held are output. Are added, and the PP is detected and calculated.
Are held by the PP hold circuits 4C and 5C.

On the other hand, from the reset / hold clock generation circuit 11, the PP reset / hold of the first and second PP detection operation hold circuits 4, 5 and the first and second hold circuits 6, Signals d, h, f, and k for turning on / off the first and second signal passing switches 6A, 7A connected to 7 are output.

That is, the reset / hold clock circuit 11 operates with the output signal a from the eccentricity detector 2 and generates a zero-cross point once per rotation of the turbine axle 1.
The first flip-flop circuit 11A operates. Also,
The output signal of the first flip-flop circuit 11A is input to the second flip-flop circuit 11B, and the reset and hold circuit operates once every two rotations.

The output signal of the second flip-flop circuit 11B is supplied to first and second filters 11C and 11C.
D, and the delayed first and second filters 11
C, 11D output signal and second flip-flop circuit 1
1B is output from the first and second AND circuits 11E and 1E.
By taking the logical product (AND) at 1F,
It is obtained as a reset / hold signal for the second PP hold circuits 4 and 5. Further, the output signals of the first and second AND circuits 11E and 11F and the delayed output signals of the first and second filters 11C and 11D are output by the first and second exclusive OR circuits 11G and 11H. The exclusive OR is obtained as a hold signal for the first and second hold circuits 6 and 7.

In this case, the reset / hold signal of the second PP hold circuit 5 is operated such that the reset / hold operates at a period completely opposite to that of the reset / hold signal of the first PP hold circuit 4. can get. That is, the first
When the PP hold circuit 4 is holding, the second PP hold circuit 5 is reset (sampled), and conversely, the second PP hold circuit 5 holds. At this time, the first PP hold circuit 4 is reset (sampled), and PP is detected and calculated at different timings.

Next, the first and second hold circuits 6, 6
The hold values l and m obtained in step 7 are selected by the low hold value selection circuit 8 to select the lower hold value, and the zero-span adjustment circuit 9 performs zero-span adjustment so that a predetermined output signal is obtained. The signal is further converted into an operation signal of an external instrument by the V / I conversion circuit 10 and output.

As described above, in the eccentricity measuring apparatus of the present embodiment, a certain eccentricity of the turbine axle 1 is
Since the two PP hold circuits 4 and 5 sample and hold at a cycle opposite to each other and always select a low hold value, a deviation of the turbine axle 1 occurs and a large eccentric amount is generated. , The higher output is not sent to the outside, and the accurate eccentric amount can be sent continuously.

Further, since the reset / hold signal is generated based on the output signal of the eccentricity detector 2, the amount of eccentricity synchronized with the rotation speed of the turbine axle 1 can be measured, and the minimum time It is possible to perform the eccentricity measurement. As described above, even when the center of the amount of eccentricity of the turbine axle 1 is shifted, the amount of eccentricity can be measured accurately and in a minimum time. It should be noted that the present invention is not limited to the above-described embodiment, and can be similarly implemented in the following manner.

(A) In the above embodiment, the reset
The hold clock generation circuit 11 includes two flip-flop circuits 11A and 11B and two filters 11C and 11C.
D, two AND circuits 11E and 11F and two exclusive OR circuits 11G and 11H have been described, but it is needless to say that the present invention is not limited to this.

(B) In the above embodiment, the first and second PP detection operation hold circuits 4 and 5 and the first and second PP
It is needless to say that the hold circuits 6 and 7 are not limited to the circuit configuration described above.

[0037]

As described above, according to the present invention, a certain amount of eccentricity of the axle to be monitored is sampled and held by the two eccentricity maximum amplitude value detection calculation holding means in mutually opposite periods. Then, since the lower hold value is always selected and output from each hold value, even when the center of the eccentric amount of the axle is shifted, the eccentric amount can be measured accurately and in the shortest time. An extremely reliable eccentricity measuring device can be provided.

[Brief description of the drawings]

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

FIG. 2 is a time chart for explaining the operation in the embodiment.

FIG. 3 is a block diagram showing a configuration example of a conventional eccentricity measuring device.

[Explanation of symbols]

1 ... turbine axle, 2 ... eccentricity detector, 3 ... buffer,
4, 5... First and second PP detection calculation hold circuits, 4
A, 5A: first and second positive side peak value hold circuits, 4
B, 5B: first and second differential amplifiers, 4C, 5C: first and second PP hold circuits, 6, 7: first and second hold circuits, 8: low hold value selection Circuit 9, zero-span adjustment circuit, 10 V / I conversion circuit, 11 reset / hold clock generation circuit, 11A first flip-flop circuit, 11B second flip-flop circuit, 11C, 11D first, first The second filter, 11E,
11F... First and second logical product (AND) circuits, 11G,
11H: First and second exclusive OR circuits.

Claims (2)

(57) [Claims] 1. An eccentricity measuring device for measuring an eccentricity of an axle to be monitored, wherein the eccentricity detecting device is provided to face the axle and detects the eccentricity of the axle. The eccentricity maximum amplitude value is detected and calculated based on the detected eccentricity, and the mutually different
First and second eccentric amount maximum amplitude value detection operation holding means for sampling and holding at predetermined intervals by a cycle, and holding values of the respective eccentric amount maximum amplitude value detection operation hold means for each predetermined time. First
And second holding means, and operates based on the eccentricity detected by the eccentricity detecting means such that the sample hold period of each of the eccentricity maximum amplitude value detection calculation holding means is synchronized with the rotation speed of the axle. A sample and hold signal generating means for generating a sample and hold signal for each of the eccentric amount maximum amplitude value calculation operation and holding means, and generating a hold signal for each of the hold means; and detecting the two eccentric amount maximum amplitude values. Low hold value selection means for selecting a lower hold value among the hold values by the arithmetic hold means and outputting the selected hold value to the outside, wherein the sample hold signal generation means is configured such that the sample hold cycle is the maximum of each of the eccentricity amounts. sample-and-hold signal as operates exactly in reverse timing in the amplitude value detection operation hold means Generates the eccentricity measuring apparatus characterized by each of said eccentricity maximum amplitude value detecting operation hold means is adapted to generate a hold signal to hold just prior to sample. 2. The eccentricity amount detected by the eccentricity detecting means is input as the sample hold signal generating means,
A first operating at a zero crossing point per revolution of the axle
A second flip-flop circuit which receives an output signal from the first flip-flop circuit and operates at a cycle of once every two rotations of the axle; and a second flip-flop circuit. A first and a second filter for delaying an output signal, respectively, and a logical product of an output signal of the first and the second filter and an output signal of the second flip-flop circuit, respectively, A first and a second AND circuit for outputting as a sample-and-hold signal of the eccentric amount maximum amplitude value detection operation holding means, and an output signal of the first and the second AND circuit, and first and second filters Exclusive OR with the output signal of
2. The eccentricity measuring apparatus according to claim 1, further comprising first and second exclusive OR circuits outputting the hold signals of the first and second hold means.