外文文獻(xiàn)譯文和原文
譯文:
圖 2.4.9 三個(gè)轉(zhuǎn)子觀察接近傳感器:兩個(gè)轉(zhuǎn)子橫向振動(dòng)測(cè)量傳感器正交的方向和一鍵相位傳感器。示波器屏幕顯示橫向振動(dòng)波形數(shù)據(jù)從兩個(gè)側(cè)面以時(shí)間為基礎(chǔ)的傳感器。鍵相位點(diǎn)的是波形上疊加。每個(gè)轉(zhuǎn)子旋轉(zhuǎn)的的鍵相位傳感器提供了序列空白/亮點(diǎn)。識(shí)別的方向繞在示波器屏幕上: 由于信號(hào) X 的振幅峰值的發(fā)生較早比峰值的振幅 Y(在時(shí)間上),所述轉(zhuǎn)子的軌道是在從 X 到 Y 的方向上,獨(dú)立于轉(zhuǎn)子的旋轉(zhuǎn)方向。還提供了顯示的信號(hào)的絕對(duì)相位,以及垂直與水平運(yùn)動(dòng)的相對(duì)相位,相對(duì)垂直頻率與水平,并與旋轉(zhuǎn)速度。
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圖 2.4.10 示波器的屏幕顯示與轉(zhuǎn)子的軌道運(yùn)動(dòng)。未經(jīng)濾波的軌道是一個(gè) 放大的轉(zhuǎn)子的中心線的橫向運(yùn)動(dòng)路徑。它的形狀是一個(gè)反映會(huì)發(fā)生什么的轉(zhuǎn)子。需要注意的是,如果將示波器設(shè)置在直流(dc),則軌道中心表示所述轉(zhuǎn)子的中 心線位置(例如軸承間隙內(nèi),在示波器上可以打上屏)。如果示波器上設(shè)置交流
(交流電),那么軌道中心將總是會(huì)出現(xiàn)在屏幕中間。從序列中的'空白'亮'點(diǎn),創(chuàng)建疊加鍵相位信號(hào),轉(zhuǎn)子的旋轉(zhuǎn)方向與軌道方向可以被確定。請(qǐng)注意,沒有關(guān) 于這個(gè)序列建立公約; 在每一個(gè)特定的情況下,它有相應(yīng)的時(shí)基波(線索轉(zhuǎn)子鍵相位缺口與投影有關(guān)示波器約定)單獨(dú)進(jìn)行調(diào)查。多頻振動(dòng)分量,已過濾的時(shí)基信號(hào)的絕對(duì)相位,提供接近換能器的轉(zhuǎn)子觀察,“滯后”(常規(guī)正號(hào)),一個(gè) 空白(或亮)的鍵相器的點(diǎn)從一開始作為相位測(cè)量第一正峰值的信號(hào)。過濾組 件的轉(zhuǎn)子的橫向振動(dòng)的相位表示旋轉(zhuǎn)機(jī)械中的最重要的診斷工具。鍵相傳感器 的轉(zhuǎn)子橫向振動(dòng)數(shù)據(jù)聯(lián)系到其旋轉(zhuǎn)運(yùn)動(dòng):
監(jiān)測(cè)旋轉(zhuǎn)機(jī)械振動(dòng)
圖 2.4.11 使用鍵相位標(biāo)記,以確定轉(zhuǎn)子軌道軌道旋轉(zhuǎn)頻率比,需要注意的是兩個(gè)連續(xù)的鍵相位標(biāo)記之間有一個(gè)旋轉(zhuǎn)的轉(zhuǎn)子。 旋轉(zhuǎn)振動(dòng)頻率比的評(píng)價(jià)
(圖 2.4.11)。鍵相傳感器所提供的信息是極其寶貴的轉(zhuǎn)子動(dòng)平衡程序,在診斷其他各種機(jī)器故障,如轉(zhuǎn)子固定部分摩擦或轉(zhuǎn)子開裂是無價(jià)的。
2.4.2 傳感器的選擇
傳感器安裝在一臺(tái)機(jī)器上,是當(dāng)今先進(jìn)的心臟計(jì)算機(jī)監(jiān)控系統(tǒng)。機(jī)器監(jiān)控系統(tǒng)傳感器的選擇取決于機(jī)器上的建設(shè),估計(jì)類型的振動(dòng)故障和參數(shù),評(píng)估故障,機(jī)器的內(nèi)部和外部環(huán)境,轉(zhuǎn)速范圍廣,預(yù)期機(jī)動(dòng)態(tài)/振動(dòng)行為。機(jī)器結(jié)構(gòu)強(qiáng)加限制在傳感器安裝。環(huán)境參數(shù),如溫度、工作流體壓力、腐蝕性和/或輻射表示傳感器操作條件。預(yù)期的機(jī)器的動(dòng)態(tài)行為,其可能的故障類型,回答問題什么參數(shù)來衡量,什么是振動(dòng)信號(hào)電平,信號(hào)噪聲比和頻率范圍。
它必須被很好地理解,旋轉(zhuǎn)機(jī)械的轉(zhuǎn)子的任何表示源振動(dòng)。通過測(cè)量轉(zhuǎn)子的振動(dòng),得到的直接信息。當(dāng)測(cè)量外殼振動(dòng)速度傳感器或加速度傳感器,振動(dòng)
的信息是間接的,扭曲的外殼傳遞。這也是不完整的,不能得到轉(zhuǎn)子的軌道和內(nèi)間隙的中心線位置,在低頻率范圍內(nèi)的信號(hào)的分辨率差。
一個(gè)選擇的傳感器和進(jìn)一步的數(shù)據(jù)管理系統(tǒng)可以在一個(gè)廣泛的基礎(chǔ),通常, 除以旋轉(zhuǎn)機(jī)械分類,比如“關(guān)鍵的“基本”和“平衡的植物”(通用機(jī)器) 。不能幸免,大型和昂貴的機(jī)器,以及那些機(jī)器將創(chuàng)建一個(gè)重大危險(xiǎn)源或生產(chǎn)損失, 如果他們突然變得不起作用,被列為關(guān)鍵設(shè)備。因此,主要的因素是,一個(gè)危險(xiǎn) 的生產(chǎn)失敗的一個(gè)給定的機(jī)器。關(guān)鍵設(shè)備必須要小心使用最好的上線系統(tǒng)。另 一方面,很容易更換的通用的機(jī)器可以被周期性地監(jiān)視與可接受的結(jié)果,使用 便攜式儀器。后者可能代表接近傳感器集成到機(jī)器的振動(dòng)數(shù)據(jù)的簡單收藏家, 或者他們可能會(huì)周期性地安裝在機(jī)器外殼上的速度傳感器或加速度計(jì)。
2.4.3 機(jī)床操作模式的數(shù)據(jù)采集與數(shù)據(jù)處理格式
安裝在旋轉(zhuǎn)的機(jī)器的上的的在線監(jiān)測(cè)系統(tǒng)包括換能器和的數(shù)據(jù)采集和處理 硬件和軟件。這種監(jiān)測(cè)系統(tǒng)的最終產(chǎn)品應(yīng)該是人性化,充分格式化,便于在機(jī) 器健康方面的解釋。存在內(nèi)容詳實(shí)的介紹了各種格式的機(jī)器的震動(dòng)和處理數(shù)據(jù), 而應(yīng)收集在五個(gè)不同的機(jī)器運(yùn)行狀態(tài)如下:
1. 在靜止: 這被稱為為靜態(tài)數(shù)據(jù),提供了在軸承內(nèi)部的轉(zhuǎn)子靜止位置,并可能也揭示了任何外部振動(dòng)源的存在下。靜止時(shí),各種機(jī)器元素和毗鄰的建筑,如管道,結(jié)構(gòu)共振可以進(jìn)行測(cè)試,采用模態(tài)分析方法。
2. 在慢速輥,即,在低轉(zhuǎn)速(通常小于 10%的第一余額共振速度)在該狀態(tài)下, 轉(zhuǎn)子的動(dòng)態(tài)響應(yīng)主要是由于在轉(zhuǎn)子的弓和/或電氣和機(jī)械的跳動(dòng)。慢搖數(shù)據(jù)提供 為轉(zhuǎn)子的直線度檢查,和振子/轉(zhuǎn)子表面調(diào)節(jié)檢查。
3. 在啟動(dòng)時(shí):在這段短暫的狀態(tài)振動(dòng)捕獲的數(shù)據(jù)是非常重要的。它有助于確定慢輥的速度范圍內(nèi),共振速度,振動(dòng)模式,自激振動(dòng)的存在下,并提供了對(duì)模態(tài)的有效阻尼和同步的放大系數(shù)的信息。獲得最佳的數(shù)據(jù),如果啟動(dòng)的角加速度為良好的分辨率的數(shù)據(jù)與由瞬態(tài)過程的轉(zhuǎn)動(dòng)速度和低的污染是足夠小的。然而,請(qǐng)注意,如果機(jī)器顯示出高的振動(dòng)加速度緩慢更可能危及其健康,振動(dòng)源
要被淘汰。
瞬態(tài)過程的數(shù)據(jù)顯示格式是整體橫向振動(dòng)的振幅,極性和過濾的 1 波特圖并過濾其他頻率成分(圖 2.4.13 到 2.4.16),與轉(zhuǎn)速轉(zhuǎn)子中心線位置(圖
2.4.17), 頻譜級(jí)聯(lián)( 圖 2.4.18 和 2.4.19 ),轉(zhuǎn)子橫向振動(dòng)頻譜瀑布(圖
2.4.20 見 2.4.5 段)。全方位改善了簡單的獨(dú)立光譜波形完整顯示(圖 2.4.21 和 2.4.22),.在慢速輥,即,在低轉(zhuǎn)速(通常小于 10%的第一余額共振速度) 在該狀態(tài)下,轉(zhuǎn)子的動(dòng)態(tài)響應(yīng)主要是由于在轉(zhuǎn)子的弓和/或電氣和機(jī)械的跳動(dòng)。 慢搖數(shù)據(jù)提供為轉(zhuǎn)子的直線度檢查,和振子/轉(zhuǎn)子表面調(diào)節(jié)檢查。兩個(gè) XY 傳感器(參見 2.4.5 節(jié))。此信息有助于確定故障的根本原因,產(chǎn)生特定的反應(yīng)模式。全頻譜圖可伴有轉(zhuǎn)子軌道和/或時(shí)基波形序列完整的顯示(圖 2.4.21 和 2.4.22) 監(jiān)測(cè)旋轉(zhuǎn)機(jī)械振動(dòng)
圖2.4.12 極地塊轉(zhuǎn)子無補(bǔ)償(a)和(b)補(bǔ)償同步(1)振動(dòng)數(shù)據(jù)在啟動(dòng)一個(gè)橫向距離提供位移傳感器。在補(bǔ)償情節(jié),慢滾向量已經(jīng)矢量地減去。開始的情節(jié)已被移動(dòng)到零點(diǎn)。該地塊上的數(shù)字代表以轉(zhuǎn)的轉(zhuǎn)速。
圖2.4.13典型波德圖(1)過濾無償振動(dòng)轉(zhuǎn)子的同步,4.在操作的速度,即,在機(jī)器的動(dòng)態(tài)平衡:振動(dòng)信息簡稱為穩(wěn)態(tài)數(shù)據(jù)是最有意義的處理時(shí),使用時(shí)間趨勢(shì)的格式的,以評(píng)估任何惡化的動(dòng)態(tài)行為。靜態(tài)數(shù)據(jù),提供了在軸承內(nèi)部的轉(zhuǎn)子靜止位置,并可能也揭示了任何外部振動(dòng)源的存在下。靜止時(shí),各種機(jī)器元素和毗鄰的建筑,安裝在旋轉(zhuǎn)的機(jī)器的上的的在線監(jiān)測(cè)系統(tǒng)包括換能器和的數(shù)據(jù)采集和處理硬件和軟件。一個(gè)選擇的傳感器和進(jìn)一步的數(shù)據(jù)管理系統(tǒng)可以在一個(gè)廣泛的基礎(chǔ),通常,除以旋轉(zhuǎn)機(jī)械分類,比如“關(guān)鍵的“基本”和“平衡的植物”(通用機(jī)器) 。不能幸免,大型和昂貴的機(jī)器,以及那些機(jī)器將創(chuàng)建一個(gè)重大危險(xiǎn)源或生產(chǎn)損失,如果他們突然變得不起作用,被列為關(guān)鍵設(shè)備。這種監(jiān)測(cè)系統(tǒng)的最終產(chǎn)品應(yīng)該是人性化,充分格式化,便于在機(jī)器健康方面的解釋如管道,結(jié)構(gòu)共振可以進(jìn)行測(cè)試上面的運(yùn)行速度的監(jiān)測(cè)數(shù)據(jù)可以顯示在時(shí)基的波形,軌道(圖2.4.23),整體最大和最小振幅(圖2.4.24),瀑布圖(圖2.4.25),在趨勢(shì)格式的趨勢(shì),格式包括轉(zhuǎn)子中心線位置(圖2.4.26),轉(zhuǎn)子振幅和相位.
圖2.4.14 典型的波特圖轉(zhuǎn)子同步(1)過濾補(bǔ)償和無償?shù)恼駝?dòng)
圖2.4.15 轉(zhuǎn)子的垂直和水平同步1x響應(yīng)波特圖表示支持各向異性('分裂'共振),在低轉(zhuǎn)速的結(jié)構(gòu)共振。
圖2.4.16 極地地塊的轉(zhuǎn)子1x振動(dòng),測(cè)量內(nèi)側(cè)和外側(cè)的位置,覆蓋兩種模式: 平移和樞轉(zhuǎn)的轉(zhuǎn)子。
圖2.4.17 兩個(gè)接近傳感器配置在XY測(cè)量,并繪制隨時(shí)間變化,標(biāo)志著轉(zhuǎn)子轉(zhuǎn)速和機(jī)器負(fù)荷轉(zhuǎn)子中心線位置。本特利內(nèi)華達(dá)公司診斷服務(wù)的禮貌。
圖2.4.18 振動(dòng)時(shí)基信號(hào)從一個(gè)傳感器獲得的頻譜分析
圖2.4.19 頻譜級(jí)聯(lián)情節(jié)轉(zhuǎn)子振動(dòng)參展1x和流體鞭振動(dòng)。奇數(shù)高次諧波,諧波和/差也出現(xiàn)在頻譜中。
圖 2.4.20 (一)全光譜級(jí)聯(lián)包括流體旋轉(zhuǎn)(參見第 4 章第 4.2 節(jié)),(二)全
光譜級(jí)聯(lián)輕輕摩擦轉(zhuǎn)子在滑行過程中伴隨著一些轉(zhuǎn)子軌道(見第 5.6 章的轉(zhuǎn)子
振動(dòng) 5
原文:
Figure 2.4.9 Three rotor-observing proximity transducers: two rotor lateral vibration-measuring transducers in orthogonal orientation and one Keyphasor transducer. Oscilloscope screen showing lateral vibration time-base waveform data from two lateral transducers. Keyphasor dots are super-imposed on the waveforms. The Keyphasor transducer provides the sequence of blank/bright dots at each rotor rotation. Identification of the direction of orbiting on the oscilloscope screen: Since the amplitude peak of the signal X occurs earlier (in time) than the peak
of amplitude Y, the rotor orbiting is in direction from X to Y, independently of the direction of rotor rotation. The displayed signal provides also absolute phases, as well as relative phases of vertical versus horizontal motion, relative vertical frequency versus horizontal and versus rotational speed. the rotor orbiting is in direction from X to Y, independently of the direction of rotation. The signal provides also absolute phases, as well as relative phases of vertical versus horizontal motion, relative vertical frequency versus horizontal and versus rotational speed.
Figure 2.4.10 Oscilloscope screen with the rotor orbital motion display. The unfiltered orbit is a magnified path of the rotor centerline lateral motion. Its shape is a reflection of what happens to the rotor. Note that if the oscilloscope is set on direct current (dc) then the orbit center indicates the rotor centerline position (for instance within the bearing clearance, which can be marked on the oscilloscope screen). If the oscilloscope is set on ac (alternating current) then the orbit center will always occur in the middle of the screen. From the sequence of ‘blank’ ‘bright’ spots, created by superposed Keyphasor signals, the direction of rotor orbiting versus the direction of rotation can be determined. Note that there is no established convention about this sequence; in each particular case it has to be investigated individually on the corresponding time base waves (the clues are related to rotor Keyphasor notch
versus projection and to oscilloscope convention).
frequency-multiple vibration components. The absolute phase on a filtered time- base signal, provided by a rotor-observing proximity transducer, is measured as a phase ‘‘lag’’ (conventionally with positive sign) from the start of a blank (or bright) Keyphasor dot to the first positive peak of the signal. The phases of filtered components of rotor lateral vibration represent one of the most important diagnostic tools in rotating machinery. The Keyphasor transducer ties the rotor lateral vibration data to its rotational motion: it serves
Figure 2.4.11 Using rotor orbits with Keyphasor marks to determine orbiting-to- rotation frequency ratios. Note that between two consecutive Keyphasor marks there is one rotation of the rotor. for the evaluation of vibration-to-rotation frequency ratio (Figure 2.4.11). The informa-tion provided by the Keyphasor transducer is extremely valuable for rotor balancing procedures (see Section 6.1of Chapter 6),and is priceless in diagnosing various other machine malfunctions, such as rotor-to- stationary part rubs or rotor cracking.
2.4.2 Transducer Selection
The set of transducers installed on a machine is the heart of today’s sophisticated computerized monitoring systems. A selection of transducers for the machine monitoring system depends on the machine construction, estimated types of vibrational malfunctions and parameters, which assess the malfunction, machine internal and external environ-ment, rotational speed range, and the expected machine dynamic/vibrational behavior. The machine structure imposes limitations parameters, such as temperature, working fluid pressure, corrosiveness, and/or radiation indicate the transducer operational conditions. The expected machine dynamic behavior and its possible malfunction types answer the questions regarding what parameters to measure, and what are vibration signal levels, signal-to-noise ratio
and frequency range. It has to be well understood that the rotor of any rotating machine represents a source of vibration. By measuring the rotor vibrations, direct informatio is obtained. When measuring casing vibrations using velocity transducers or accelerometers, the vibrational information is indirect, distorted by casing transmissibility. It is also incomplete, as rotor orbits and centerline positions within clearances cannot be obtained, and the signal resolution in the low frequency range is poor.
A selection of transducers and further data management systems can be made on a broad basis, generally, by dividing rotating machinery into categories, such as ‘‘critical’’, ‘‘essential’’, and ‘‘balance-of-plant’’ (general purpose machines). Large and expensive machines, which cannot be spared, as well as those machines which would create a major hazard or production loss if they suddenly became inoperative, are classified as critical machines. The main factor is, therefore,a vulnerability of production to failure of a given machine. The critical machines have to be carefully instrumented with the best on-line systems. On the other hand, the easily replaceable general-purpose machines may be periodically monitored with acceptable results, using portable instruments. The latter may represent simple collectors of vibrational data from proximity transducers incorporated into the machine, or they may be velocity transducers or accelerometers periodically installed on the machine housings.
2.4.3 Machine Operating Modes for Data Acquisition and Data Processing Formats
The online monitoring systems installed on rotating machines include transducers and data acquisition and processing hardware and software. The end product of such monitoring systems should be user-friendly, and adequately formatted for easy interpretation in terms of the machine health. There exist a
variety of informative presentation formats of the machine vibration and process data, which should be collected during five different machine operational states as follows:
1. At rest: The data, which is referred to as static data, provides the rotor static position within the bearings, and may also reveal the presence of any external source of vibration. At rest, the structural resonances of various machine elements and adjoining constructions, such as pipelines, can be tested, using modal analysis methods.
2. At slow roll, i.e., at low speed (typically less than 10% of the first balance resonance speed). In this condition, the rotor dynamic response is mainly due to rotor bow and/or electric and mechanical runout. The slow roll data serves for the rotor straightness check, and for the transducer/rotor surface conditioning check-up. The slow roll data are vital in rotor crack diagnosis and in the machine balancing process (see Sections 6.1 and 6.5 of Chapter 6). At the slow roll speed, the 1 slow roll vector can be identified and then used to compensate Bode and polar plots obtained during startup or shutdown of the machine (Figure 2.4.12).
3. At start-up: Vibrational data captured during this transient state is extremely important. It helps to identify slow-roll speed range, resonance speeds, vibration modes, presence of self-excited vibrations, and provides information on modal effective damping and synchronous amplification factors. The best data is obtained if the start-up angular acceleration is small enough for good resolution of data versus rotational speed and low contamination by transient processes. Note, however, that if the machine exhibits high vibrations the slow acceleration may even more jeopardize its health; the source of vibrations have to be eliminated.
The data display formats for transient processes are overall lateral vibration
amplitudes, polar and Bode plots of filtered 1 and filtered other frequency components (Figures 2.4.13 to 2.4.16), rotor centerline position versus rotational speed (Figure 2.4.17), spectrum cascade (Figures 2.4.18 and 2.4.19), and rotor lateral vibration full spectrum cascades (Figure 2.4.20; see subsection 2.4.5). The full spectrum is an improvement over simple independent spectra from two XY transducers (see Section 2.4.5). It provides better insight into the rotor orbital path and orbiting direction of vibration frequency components. This information helps in identification of the root cause of a malfunction generating a specific response pattern. The full spectrum plots may be accompanied by a sequence of rotor orbits and/or time-base waveforms for complete display (Figures 2.4.21 and 2.4.22).
Figure 2.4.12 Polar plots of rotor uncompensated (a) and compensated (b) synchronous (1) vibration data during start-up provided by one lateral proximity displacement transducer. In the compensated plot, the slow roll vector has been vectorially subtracted. The beginning of the plot has been moved to zero point. The numbers on the plots represent rotating speed measured in rpm.
Figure 2.4.13 Typical Bode plot rotor of synchronous (1) filtered uncompensated vibrations.
4. At operating speed, i.e., at dynamic equilibrium of the machine: The vibration information referred to as steady-state data is most meaningful when processed using time-trend formats in order to assess any deterioration in the dynamic behavior. The data monitored at the operating speed can be displayed in the time-base waveform, orbit (Figure 2.4.23), overall maximum and minimum amplitude (Figure 2.4.24), waterfall spectrum (Figure 2.4.25), and in trend formats. The trend formats include rotor centerline position (Figure 2.4.26), rotor amplitude and phase .
Figure 2.4.14 Typical Bode plot of rotor synchronous (1) filtered compensated and uncompensated vibrations.
Figure 2.4.15 Rotor vertical and horizontal synchronous 1 response plots indicating support anisotropy (‘split’ resonance) and structural resonances at low rotational speed.
Figure 2.4.16 Polar plots of rotor 1 vibrations, measured at inboard and outboard locations, covering two modes of the rotor: translational and pivotal.
Figure 2.4.17 Rotor centerline position measured by two proximity transducers in XY configuration and plotted versus time, marking rotor rotational speed and machine load. Courtesy of Bently Nevada Corporation Diagnostic Services.
Figure 2.4.18 Spectrum analysis of vibration time-base signal obtained from one transducer.
Figure 2.4.19 Spectrum cascade plot of rotor vibrations exhibiting 1 and fluid whip vibrations. Odd higher harmonics and sum/difference harmonics are also present in the spectrum.
Figure 2.4.20 (a) Full spectrum cascade of a rotor vibrations including fluid whirl (see Section 4.2 of Chapter 4). (b) Full spectrum cascade of a lightly rubbing rotor during coast down accompanied by some rotor orbits (see Section 5.6 of Chapter 5).