This study shows that while diagnostic estimation of shaft movement asynchronous and noise components of vibration signal acts like restrictions decreasing reliability of measuring information. Proposed method and algorithm of separate tolerance control of parameters of vibration signal synchronous, asynchronous and noise components spectrums that provide increasing of measuring information reliability via decreasing of disturbing components. Generic parameters of distribution of energy spectrum for every component of vibration signal performed. Application of separate tolerance windows for generic indicators of energy spectrum of vibration signal synchronous, asynchronous and noise components enables to advance usage of informational capabilities of vibration signal. Performance of generic indicators enables algorithmization of process of detecting of changing’s in technical state of rotor, stator and energy elements of rotary machine

Shantyr, A.

Shantyr, S.

Electronic Archive of Kyiv Polytechnic Institute

UDC 004.67: 681.518.5S. Shantyr, A. ShantyrINCREMENT IN INFORMATION AND ALGORITHMIZATION OF CURRENT SPECTRUM TOLERANCE CONTROLFOR ROTARY MACHINEIntroductionExisting systems for vibration control perform estimation of machinery technical state via method of current spectrum tolerance control of vibration signal [1–4] using tolerance windows. Author’s study of spectrum of rotary machine vibration signal [5, 6] shows occurrence of three well-recognized components in its composition: comb spectrum of synchronous component of vibration signal { ( )}i i rotor NG G f i F   ; concentrated (lobed) spectrum of asynchronous component of vibration signal ( )aSCG f , ( )aSC lobe aSCf F F   ; nonuniform spectrum of noise component of vibration signal ( )NCG f , ( , )low highNC NCf F F .Split usage of structural components spectrums enables increasing of amount of rotary machine technical state information pumped from vibration signal.Problem definitionArticle purpose – to design method and algorithm for processing current spectrum of vibration signal to provide increment in information of its tolerance control via usage of structural components spectrums.Structure chart of system for current spectrum tolerance control for rotary machineStructure chart of system for current spectrum tolerance control for rotary machine realizing developed method (fig. 1) includes linear measuring transducer L (amplifier, former of amplitude-frequency characteristic, integrator, stc.) of input measuring signal; analog-digital converter (ADC); selectors of synchronous (Selector SC) and asynchronous (Selector aSC) structural components of vibration signal; channels for separate tolerance control of generic numerical parameters of spectrums of synchronous, asynchronous and noise structural components. In each channel numerical value of generic parameter enters threshold device (TD) and decision-making device (DMD) about technical state of rotary machine (S).Fig. 1. Structure chart of system for current spectrum tolerance control for rotary machineVibration signal ( )v t  enters the system and contain synchronous ( )SCv t , asynchronous ( )aSCv t  and noise ( )NCv t  components( ) ( ) ( ) ( )SC aSC NCv t v t v t v t   . (1)Vibration signal ( )v t  spectrum is on fig. 2. Control purpose is detection and estimation of variation energy spectrum of vibration signal structural components during operation of rotary machine.Fig. 2. Spectrum of rotary machine vibration signal ( )v tControl of spectrum of vibration signal synchronous componentTolerance control of vibration signal synchronous component executed using its current energy spectrum { ( )}i NG t  (fig. 3). Position dispersion on frequencies axis and oscillations power variance of spectral lines are indicators of variance of synchronous component energy spectrum.Fig. 3. Spectrum of synchronous component of rotary machine vibration signalExperimentally detected that main reason of spectral lines position dispersion on frequencies axis is deviation of rotor speed. To eliminate that dispersion way of registration of spectral lines position changed: on horizontal axis marked not frequency but frequency multiplicity of rotor speed f rotorK f F .As the result every spectral line stands on fixed position suitable to its number1,2,..., ,...,linefK i N .Carried out studies show that process { ( )}i NG t  on sufficiently great, but limited intervals of observation time obsT  has quasistationary nature, and it enables to use sample mean of process for tolerance control: sample mean power of every i spectral line1( ) ( )obst Ti iobs tG t G t dtT  ,    1,2,...,i N .It’s known [2, 7] that redistribution of spectral lines power is sign of changing of technical state of machinery during operation. To account quantitatively change of energy of every separate line measuring of average power level shift of every i  spectral line relatively to reference value { ( ) ( ) }refi i i NG t G t G    included in scheme (fig. 1).Following parameters of energy spectrum of vibration signal synchronous component defined as generic indicators of changing of technical state of machinery: average power of vibration signal synchronous component1( ) ( )NSC iiG t G t ; variance of spectrum effective bandwidth2 ( )( )( )i ieffSCf G tB tG t   .As opposed to operating systems for vibration control [3], where for each i  spectral line set tolerance window determining two reference indicators (bandwidth (horizontal size of window refif ) and power (vertical size of window refiG )), scheme (fig. 1) uses two-dimensional tolerance window for generic parameters of energy spectrum of vibration signal synchronous component: for power – tolerance for power of vibration signal synchronous component( )SC ref tolG t G G  ; for frequency - maximum permissible value of spectrum effective bandwidth shift( )eff tolB t B   .Generic numerical parameters of spectrum of vibration signal synchronous component applied as indicators of technical state of rotary machine rotor element.Control of spectrum of vibration signal asynchronous componentTolerance control of vibration signal asynchronous component executed using its current energy spectrum ( , )aSCG f t . Position shift on frequencies axis and power variance of oscillations are indicators of variance of asynchronouscomponent energy spectrum.Form of spectrum of vibration signal asynchronous component is on fig. 4. Figure shows that main sign of spectrum of vibration signal asynchronouscomponent is well-recognized main lobe. Structure of spectrum side components has no readable elements.a)b)Fig. 4. Spectrum of asynchronous component of rotary machine vibration signal: a) 1, 2,...,1200fK  ; b) 830, 831,..., 860fK Position parameter of spectrum of vibration signal asynchronouscomponent on frequencies axis( , )( )( , )aSCaSCaSClobeaSCf G f t dfF tG f t df .Power of vibration signal asynchronous component( ) ( , )lobe aSClobe aSCF FaSC aSCF FG t G f t df  .Generic numerical parameters of spectrum of vibration signal asynchronous component defined as: sample mean1( ) ( )obst Tlobe lobeobs tF t F t dtT  ; sample mean1( ) ( )obst TaSC aSCobs tG t G t dtT  .Tolerance window for generic parameters of energy spectrum of vibration signal asynchronous component includes: for power – tolerance for power of vibration signal asynchronous component( )aSC ref tolG t G G  ; for frequency - maximum permissible value of spectrum effective bandwidth shift( )lobe ref tolF t F F  .Generic numerical parameter of spectrum of vibration signal asynchronous component applied as indicators of technical state of rotary machine stator element.Control of spectrum of vibration signal noise componentTolerance control of vibration signal noise component executed using its current energy spectrum ( , )NCG f t . Power variance and its distribution in energy spectrum of vibration signal noise component are indicators of variance of noise component energy spectrum. Typical form of spectrum of vibration signal noise component is on fig. 5. Numerical parameters of spectrum of vibration signal noise component defined as: power of vibration signal noise component( ) ( , )highNClowNCFNC NCFG t G f t df  ; effective bandwidth of spectrum of vibration signal noise component2C   ( , )( )( )NCN effNCf G f t dfB tG t.Fig. 5. Spectrum of noise component of rotary machine vibration signalGeneric numerical parameters of spectrum of vibration signal noise component defined as: sample mean1( ) ( )obst TNC NCobs tG t G t dtT  ; sample meanC   C   1( ) ( )obst TN eff N effobs tB t B t dtT  .Tolerance window for generic parameters of energy spectrum of vibration signal noise component includes: for power – tolerance for power of vibration signal noise component( )NC ref tolG t G G  ; for frequency – maximum permissible value of spectrum effective bandwidth shiftC ( )N  eff ref tolB t B B  .Generic numerical parameters of spectrum of vibration signal noise component applied as indicators of technical state of rotary machine energy element.FindingsThis research shows that while diagnostic estimation of shaft movement asynchronous and noise components of vibration signal acts like restrictions decreasing reliability of measuring information.Proposed method of separate tolerance control of parameters of vibration signal synchronous, asynchronous and noise components spectrums that enables increasing of measuring information reliability via decreasing of disturbing components.Generic parameters of distribution of energy spectrum for every component of vibration signal performed. That enables decreasing of number of controlled indicators of technical state of rotary machine.Application of separate tolerance windows for generic indicators of energy spectrum of vibration signal synchronous, asynchronous and noise components enables to advance usage of informational capabilities of vibration signal. Performance of generic indicators enables algorithmization of process of detecting of changing’s in technical state of rotor, stator and energy elements of rotary machine.Father studies are planned to be directed on statistical synthesis and studying gauge realizing proposed method and algorithm of processing of current spectrum of rotary machine vibration signal.References1. Генкин М. Д., Соколова А. Г. Виброакустическая диагностика машин и механизмов. – М.: Машиностроение, 1987. - 288 с.2. Ольсен У. Измерение, контроль, диагноз и устранение колебаний машин. – Дармштадт: Карл Шенк АГ, - 71 с.3. Система для мониторизации состояния машинного оборудования типа 3542. 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Increment in information and algorithmization of current spectrum tolerance control for rotary machine

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