An introduction to vibration analysis theory and practice. The signals were acquired from faulty motor and from the other motor. The high frequency spectral analysis of vibration and current. It is important to understand the relationship between the time. Pdf engineering vibration books collection free download. Health monitoring of induction motor through vibration analysis neliti. The vibration analysis series is designed for new students who have minimal knowledge of predictive.
The difficulty of detecting incipient failures in the field makes the performance of a thorough torsional vibration analysis an essential component of the turbomachinery design process. The vibration analysis is one of the most important tests for understanding what is happening in a machine. Specialized vibration training courses such as time waveform analysis can also be beneficial. Vibration analysis is one of the most successful techniques used for condition monitoring of induction motors. The series covers the introduction to vibration analysis, theory, data collection, and data analysis.
To help determine which of the two tra is required to separate out specific. Analyzing vibration data in the time domain amplitude plotted against time is limited to a few parameters in quantifying the strength of a vibration profile. A good routine vibration program using a portable data collector, or permanent online vibration monitoring, will become the foundation of any predictive maintenance initiative. By utilizing current demodulation, the speed of the motor can be identified by a peak in the spectrum and monitored for changes in amplitude. A 4pole motor runs at a speed less than 1800 rpm or 30 hz and so on. This paper presents the vibration analysis and results of an induction motor through two kinds of magnetomechanical coupling methods. You may be tasked with solving a vibration problem, or you may be overseeing someone else and you need to understand the process. Psd a power spectral density psd takes the amplitude of the fft, multiplies it by its complex conjugate and normalizes it to the frequency bin width. The existing motor frame is made of metal materials. By comparing the calculated natural frequencies and the mode shapes with the results obtained from experimental modal testing, the effects of the teeth of the stator, windings, outer casing, slots, endshields and support on the. This suggests a combination of problems, including either misalignment or a problem with the sole plate or base. So, what we can do is take it one step at a time and. Switching between time and frequency is a common tool used for analysis. Motor current infrared thermography 45% vibration analysis.
Pdf one of the factors that cause the failure of induction motors which are used intensively in industry is the unbalanced loading of the motor. We specialize in threephase ac motor repair through 1500 hp 230460 v, 23004160 v. Beginning vibration analysis with basic fundamentals. Regardless of the scope of the study, a similar process will be. Formal vibration analysis training and balancing training from an organization like technical associates of charlotte can provide an analyst with valuable information and understanding of fan. Identifying the vibration problems that can occur in induction motor drives have an added complexity due to the rotating magneticfields in the machine. Beginning vibration analysis connection technology center, inc. Pdf vibration analysis of an induction motor joseph lai. Pdf vibration analysis of induction motors with unbalanced loads. These vibration signatures can be correlated to physical phenomena, making it possible to use vibration. Fault detection of the electrical motors based on vibration analysis. The top and best engineering vibration books collection are listed in the.
The efficiency of this technique for diagnosing electromagnetic problems in the motor depends on the ability to analyse vibration data. Spectral content of current probe signal depends on the motor and motor speed. Please supply oil pump information to ensure analysis that is more accurate. This paper covers the basic idea behind the vibration analysis and uses that information to reduce failures and thus save resources.
Motor vibration monitoring vibration on induction motors is at the core of any predictive maintenance program. Pdf vibration analysis of an induction motor joseph. The vibration of any object in motion is characterized by variations of amplitude, intensity, and frequency. Pdf vibration analysis of induction motors with unbalanced. Pdf with the advent of power electronics, variable speed induction motors are finding increasing use in industries because of their low cost. Vibration is an oscillating motion about equilibrium so most vibration analysis looks to determine the rate of that oscillation or the frequency, which is proportional to the systems stiffness. In this paper, considerations given to modelling the vibration behaviour of a 22 kw induction motor are discussed. The computation results are validated by comparing them. Vibration analysis can help you detect a wide variety of fault conditions. Because the frequency spectrum is derived from the data in. How basic principles of vibration analysis might be applied in a typical inplant situation can be illustrated with a pump and motor unit that shows high vertical frequencies at one end of the motor and high axial readings at the other. The limits apply to a motor mounted on a seismic mass, and uncoupled or coupled to a piece of equipment in a way that eliminates any vibration in the driven equipment.
Typical applications demand vibration measurements in the horizontal, vertical and axial direction on both the inboard and outboard motor bearings. Analysis of motor fan radiated sound and vibration. The damp ratio of the cfrp motor frame is calculated by the damp prediction model based on strain energy, which is verified by the combination of the. A vibration fft fast fourier transform spectrum is an incredibly useful tool for machinery vibration analysis. We offer vibration analysis,condition monitoring, laser alignment,dynamic balancing,shaft and bearing replacement for air handlers,motors and cooling towers as well as complete teardown and rebuild services specializing in flakt,woods and joy vaneaxial fans.
The induction motor is the most widely employed industrial electricdrive. A basic understanding of the principles involved, together with a simple troubleshooting guide and the right analysis. Each type of fault, electrical faults or mechanical faults, produces a vibration whit a specific frequency. We specialize in threephase ac motor repair through 1500 hp 230460 v, 23004160 v, dc motor repair through 500 hp.
Internal combustion engine vibrations and vibration isolation. Vibration analysis training online training courses. Vibration analysis starts with a timevarying, realworld signal from a transducer or sensor. It is important to understand the relationship between the time waveform and the frequency spectrum. Me 563 mechanical vibrations fall 2010 12 1 introduction to mechanical vibrations 1. Formal vibration analysis training and balancing training from an organization like technical associates of charlotte can provide an analyst with valuable information and understanding of fan problems detected by vibration analysis.
A properly balanced and aligned motor has a frequency peak related to its speed that is barely visible. The efficiency of this technique for diagnosing electromagnetic problems in the motor. Induction motor fault diagnosis based on vibration analysis a case study journal on processing and energy in agriculture 17 20 1 49 radial and axial vibration signals were recorded, containing 100. The level of vibration and the pattern of the vibration tell us something about the internal.
Typical applications demand vibration measurements in the horizontal, vertical and axial. The vibration analysis series is designed for new students who have minimal knowledge of predictive maintenance and machinery vibration analysis. Arrange meeting with the supplier to identify reason for high vibration on the lp male screw. How basic principles of vibration analysis might be applied in a typical inplant situation can be illustrated with a pump and motor unit that shows high vertical frequencies at one end of the motor and high. Electric motors always have frequency peaks at shaft rotational speed and. Application notes vibration diagnostics for industrial. Torsional vibration analysis of synchronous motordriven. If a machinery problem exists, fft spectra provide information to help determine the source and cause of the problem and, with trending, how long until the pr oblem becomes critical. The vibration signature changes as the condition changes.
For example, a vibration peak occurring at the fan speed is most likely a sign of wheel unbalance and can most often be remedied with minor trim balancing. Although any system can oscillate when it is forced to do so externally, the term vibration in mechanical engineering is often. Symptom of high vibration cause test or check correction. Pdf vibration analysis of an electric motor researchgate. These operational forces cause forced vibration and may originate from the rotating parts or operating conditions flow quantity, pressures, speed and arrangement. In this paper, a carbon fiber reinforced plastic cfrp motor frame, which uses material damping to reduce vibration amplitude, which is proposed to design and manufacture low vibration motors. For example, a vibration peak occurring at the fan speed is most likely a sign of wheel unbalance and can most often be remedied with minor trim. By utilizing current demodulation, the speed of the motor can be identified by a peak in the spectrum and monitored for. The level of vibration and the pattern of the vibration tell us something about the internal condition of the rotating component. The vibration pattern can tell us if the machine is out of balance or out of alignment.
Index termsantivibration mount, engine vibration, isolator. This document was created by field experienced skf application engineers using measurements obtained with skf. Page 1 of 11 the influence on torsional vibration analysis of electromagnetic effects across an induction motor air gap e. A vibration spike that occurs at the motor rpm could be an indication of motor pulley unbalance. Always present but excessive amplitude or multiple harmonics can indicate a problem. A brief tutorial on machine vibration by victor wowk, p. Here below list shows the mostly used engineering vibration books by students of top universities, institutes and colleges.
Analysis of motor fan radiated sound and vibration waveform. If a machinery problem exists, fft spectra provide information to help determine the source. Further analysis of the vibration spec sources to each measurement point. The purpose of this tutorial is to provide sufficient knowledge to understand machine vibration diagnosis.
On the following page is a sketch showing a geared motor producing three different forms of vibration. Beginning vibration 2 introduction understanding the basics and fundamentals of vibration analysis are very important in forming a solid background to analyze problems on rotating machinery. By comparing the calculated natural frequencies and the mode shapes with the results. Measuring, trending, alarming and analyzing fan and motor vibration will provide earlier warning of developing problems and allow replacement parts to be ordered. We offer vibration analysis,condition monitoring, laser alignment,dynamic balancing,shaft and. Frequency analysis is the essence of vibration analysis and enables the satisfactory resolution of most machine problems. An antivibration mount can be constructed from a number of different materials, rubber has many inherent qualities which make it an ideal solution for this application.
If vibration analysis is being done on a changing environment, a spectrogram can be a powerful tool to illustrate exactly how that spectrum of the vibration changes. More stringent specifications regarding motor vibration call for maximum velocity levels of 0. Vibration and motor current analysis of induction motors to. The computation results are validated by comparing them with. Keywords condition monitoring, diagnostics, electrical faults, induction motors, twice line frequency, vibration analysis. Vibration analysis of an induction motor sciencedirect. An antivibration mount can be constructed from a number of different materials. Vibration diagnostic guide vibration diagnostic guide part 1 this guide is designed to introduce machinery maintenance workers to condition monitoring analysis methods used for detecting and. Research purpose in many cases, because noise level of fan depends on the noise level of the whole motor, it is important to reduce the noise. In this paper, a carbon fiber reinforced plastic cfrp motor frame, which uses material damping to reduce vibration amplitude, which is proposed to. Vibration diagnostic guide vibration diagnostic guide part 1 this guide is designed to introduce machinery maintenance workers to condition monitoring analysis methods used for detecting and analyzing machine component failures. Vibration analysis of induction motors with unbalanced loads. Vibration analysis may be undertaken as a standalone process, or may be part of a machine section audit or comprehensive machine analysis.
This paper presents briefly some electrical and mechanical faults in induction motors and how these faults influence the motor vibration. Aside from typical mechanical issues, such as misaligned couplings and. We have been serving industry and municipalities since 1952. Fault detection of the electrical motors based on vibration. Fundamentals of vibration measurement and analysis explained.
Vibration analysis is a process of looking for anomalies and monitoring change from the established vibration signature of a system. This vibration reduces the expected life of the pump bearings and other components. Antivibration mounts avms are the structures used to absorb the vibrations and dampen the harm causing forces. Symptom of high vibration cause test or check correction subsynchronous a. Identifying the vibration problems that can occur in inductionmotor drives have an added complexity due to the rotating. Vibration measurement and analysis broadband vibration measurement is the most widely used and costefficient method for the diagnosis of overall machine condition.
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