A diagnostic of induction motors supplied using frequency converter basing on current and power signal analysis (original) (raw)
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2014 16th International Power Electronics and Motion Control Conference and Exposition, 2014
A method for calculation of an induction motor vibration power in frequency domain on the basis of harmonic composition of the signal of vibration acceleration or vibration velocity is offered. When this method is realized, there are no problems connected with integration of continuous signals in time domain. To estimate the efficiency of the proposed method the root-mean-square values of vibration power are calculated on the basis of harmonic composition of vibration velocity for most common induction motors fault types. It is shown that, when the root-mean-square values of vibration velocity are the same, the root-mean-square values of vibration power significantly differ, which may result in wrong diagnostics of induction motor faults. Streszczenie. W artykule zaproponowana została metoda obliczeń drgań mocy silników indukcyjnych w obszarze częstotliwościowym przy użyciu składowych harmonicznych sygnału akceleracji bądź szybkości drgań. Podczas używania tej metody nie u8jawniają się problemy związane całkowanie sygnałów ciągłych w obszarze czasu. Aby oszacować efektywność proponowanej metody wartości skuteczne mocy drgań zostały obliczone na podstawie składowych harmonicznych szybkości drgań dla większości typów defektów silników indukcyjnych. Zostało pokazane, że podczas gdy wartości skuteczne prędkości drgań są takie same, wartości skuteczne mocy drgań są znacząco różne. Stąd może wynikać błędna diagnostyka defektów silników indukcyjnych. (Oszacowanie efektywności zastosowania drgań mocy do diagnostyki silników indukcyjnych)
New Approach of Parametric Spectral Analysis Used in the Diagnosis of Induction Motors
2005
Today, in response to the industrial requirements, the diagnosis and monitoring of the electric motors, turning at constant and/or variable speed, are much requested. Several works show that the faults were often studied by the analysis of the supply current. Many schemes have been proposed, all based on the Fourier analysis. However, this analysis is badly adapted to these applications. Indeed, the signals used are strongly no stationary. New tools are thus necessary. In this article, a technique for the faults detection in the induction motors is proposed. It's based on spectral estimate using the least squares approach. The stator current is a harmonic signal. It is thus necessary to know the various amplitudes, frequencies and phases of its spectral components. In this paper, a new approach of parametric spectral analysis is proposed. This technique is used for the faults detection in the induction motors. The fault detection in these motors is based on the analysis of the ...
Estimation of the efficiency of vibration power application for induction motor diagnostics
Przegląd Elektrotechniczny, 2014
A method for calculation of an induction motor vibration power in frequency domain on the basis of harmonic composition of the signal of vibration acceleration or vibration velocity is offered. When this method is realized, there are no problems connected with integration of continuous signals in time domain. To estimate the efficiency of the proposed method the root-mean-square values of vibration power are calculated on the basis of harmonic composition of vibration velocity for most common induction motors fault types. It is shown that, when the root-mean-square values of vibration velocity are the same, the root-mean-square values of vibration power significantly differ, which may result in wrong diagnostics of induction motor faults. Streszczenie. W artykule zaproponowana zostala metoda obliczen drgan mocy silnikow indukcyjnych w obszarze czestotliwościowym przy uzyciu skladowych harmonicznych sygnalu akceleracji bądź szybkości drgan. Podczas uzywania tej metody nie u8jawniają ...
Diagnosis of induction motor faults using instantaneous frequency signature analysis
2008 18th International Conference on Electrical Machines, 2008
This paper investigates a new technique for diagnosing faults of three-phase induction motors. The Instantaneous Frequency Signature Analysis (IFSA) relates to the monitoring of the fundamental frequency modulation for the diagnosis of faults. The rotor and stator faults in induction machines involve an internal magnetic imbalance, which is reflected in the stator current. This effect may be detected by estimating the fundamental instantaneous frequency signature via stator current. The IFSA is a non-intrusive, on-line monitoring technique for the faults diagnosis.
Vibration analysis is one of the most successful techniques used for condition monitoring of induction motors. The efficiency of this technique for diagnosing electromagnetic problems in the motor depends on the ability to analyse vibration data. The aim of this presentation is to clarify the origin of the motor vibration at twice line frequency based on the classical theory of electromagnetic vibration, recent researches, and the author's many years of experience in the field of vibration diagnostics on electrical machines from different industries. The vibration component at a twice line frequency is a very important indicator when evaluating an induction motor electromagnetic system condition. The correct understanding of physical phenomena that excite the vibration at this frequency is a key factor for diagnosing induction motor problems related to electromagnetic system operation. This presentation emphasizes that the most important forcing functions exciting the vibration at twice line frequency are the radial magnetic forces produced by the fundamental rotating magnetic field and a torque pulsation due to asymmetrical voltage and current in the stator winding as a result of a supply voltage imbalance in the power line and/or internal faults in the motor electrical system. Vibration excited by these sources may be significantly amplified by a resonance condition on the entire motor structure and/or on the particular motor components (for example, a stator core).
2019 IEEE 12th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED), 2019
This work expands the classical current signature analysis in induction machines in a two-stage spectral decomposition manner. The proposed methodology can be summarized in two main steps: initially, the current signals are analyzed using a time frequency representation, with the analysis focusing on the steady-state regime; thereafter, frequency extraction is applied to the spectral signatures of interest, aiming to identify specific fault related harmonic subcomponents induced by the fault related speed ripple effect. The proposed approach is verified experimentally on a 4 kW induction motor.
— Vibration analysis is one of the most successful techniques used for condition monitoring of rotating machines. Vibration analysis is a very efficient and convenient tool for diagnosing mechanical problems in induction motors. The aim of this paper is to show that vibration analysis is an efficient tool for diagnosing electromagnetic problems in induction motors, which are very specific for this type of machines. The industry today widely uses different kinds of nonlinear systems operating in the power lines, for example, adjustable speed drives, which cause voltage distortion on the induction motor supply and in the power lines. Faulty operation of adjustable speed drives very often creates unusual voltage content on the induction motors input. Single phase load in three phase power systems may cause voltage imbalance. Induction motors operating under non-sinusoidal voltage (voltage distortion) or under non-symmetrical three phase voltage (voltage imbalance) have usually experienced significant vibration of electromagnetic nature. Vibration of an electromagnetic nature may also be a result of an internal fault in the motor. Motor vibration data contain substantial analytical information about internal motor electrical problems such as: stator and rotor winding and core condition, air gap eccentricity; and information about external electrical problems: current/voltage imbalance, voltage distortions in the power line, etc. A short theoretical analysis of electromagnetic excitation forces is included to exemplify how the internal and external electrical faults create parasitic radial forces (rotating waves) and tangential forces (pulsating torques) inside the induction motors, which deteriorates equipment health. Faults are illustrated in numerous case histories of electromagnetic problems from different industries, which result in machinery vibration that is significantly above acceptable standards. Among them are: voltage (current) imbalance, voltage waveform distortion, faulty control of ASD, motor eccentric air gap, induction motor winding (stator and rotor) damage, //and combinations of mechanical and electrical problems//.
IEEE Transactions on Industrial Electronics, 2000
Transient motor current signature analysis is a recently developed technique for motor diagnostics using speed transients. The whole speed range is used to create a unique stamp of each fault harmonic in the time-frequency plane. This greatly increases the diagnostic reliability when compared with non-transient analysis, which is based on the detection of fault harmonics at a single speed. But this added functionality comes at a price: the well established signal analysis tools used in the permanent regime, mainly the Fourier transform, cannot be applied to the non-stationary currents of a speed transient. In this paper, a new method is proposed to fill this gap. By applying a polynomial-phase transform to the transient current, a new, stationary signal is generated. This signal contains information regarding the fault components along the different regimes covered by the transient, and can be analyzed using the Fourier transform. The polynomial-phase transform is used in radar, sonar, communications and power systems fields, but this is the first time, to the best knowledge of the authors, that it has been applied to the diagnosis of induction motor faults. Experimental results obtained with two different commercial motors with broken bars are presented to validate the proposed method.
Comparative study of advanced techniques for the diagnosis of induction motors
Heritage and Sustainable Development
This work is a comparative study between the various advanced technologies of diagnosis of induction motors published recently and to make a classification of these diagnostic techniques according to their sensitivities from experimental results of stator short-circuit faults between stator turns. By using the logarithmic FFT spectrum, we can discover the best method to detect faults in their early stages so that we can predict their faults and anticipate breakdowns that can be dangerous for people or the economy.