Synthesis of diagnostic features, appropriate to the piston machines technical condition types, main failures and operation modes, arising both separately and simultaneously, and invariant to the machine construction - is an important issue. One step for this problem solution is to create the diagnostic signal model for the unit under test.
The most common model of the known is a batch action generalized model of a quasi-periodic vibroacoustic signal, proposed by V.N. Kostyukov.
This model shows that the frequency content of the low-frequency vibration spectrum and the vibroacoustic signal envelope, obtained by filtering in the high-frequency field and subsequent detection, are approximately equal. These spectra can be represented by an expansion in the characteristic frequencies, which can be divided into three groups. To evaluate the unit technical condition it is necessary to select and measure the components energy characteristics for each group.
This model describes large classes of the units under test failures. The model further development is the model, which describes the vibroacoustic signals with respect to their sources interaction, thus increasing the diagnosing accuracy and depth, but its use for developing the diagnostic algorithms is not obvious.
Therefore, it is advisable to consider a few examples of the vibroacoustic signal models when specific defects and failures occur, thus forming the piston compressors diagnostic features.
Naumenko A.P. Vibroacoustic model of the piston compressor diagnostic signal // Dynamics of systems, mechanisms and machines. - 2009. - pp. 39-44
The standard has been based on the Findings of Russian State Technical Supervision Service Committee, responsible for comprehensive monitoring systems for hazardous production facilities acceptance tests. The Committee has been created according to the Direction № R-20 from 2nd December, 2003, issued by deputy chief of Russian State Technical Supervision Service. These Findings compile a long experience in developing and implementation of real-time condition monitoring comprehensive systems for machinery and technological equipment of various industries hazardous facilities.
The standard is recommended for expert, design and industrial enterprises to help with selection and application of stationary piston compressor units in order to prevent technogenic accidents and to provide safe and resource-saving operation of equipment according to its actual technical condition.
The standard has been developed by DYNAMICS SPC: V.N. Kostyukov, A.P. Naumenko; SIU "RISCOM".
Condition monitoring of hazardous production facilities. Stationary piston compressor units of hazardous production facilities: operating vibration standards (STO 03-007-11) // Moscow: Compressor and chemical technics, 2012. - 18 p. ISBN 978-5-9902032-3-5
The tutorial considers theoretical and practical basis of machinery and mechanisms vibroacoustic analysis and malfunctions, as well as methods of vibroacoustic signals analysis.
The manual is intended for students who study disciplines ‘Automated systems for quality control and diagnostics’, ‘Methods of technical diagnostics’, ‘Vibration monitoring’ while their preparing to become specialists, masters and bachelors. The tutorial may be useful for post graduate students and specialists of non-destructive testing, who use the vibration analysis method for machinery condition monitoring and who design monitoring and diagnostic systems.
Kostyukov V.N., Naumenko A.P. Fundamentals of machinery vibroacoustic analysis and monitoring // Omsk: Publishing house of Omsk State Transport University, 2011. - 360p., ISBN 978-5-8149-1101-8
Automated Control System for Safe-Money-Saving Proactive Maintenance COMPACS® - ACS SMSPM™ COMPACS®
Accidents and breakdowns on railway transport have become more frequent, thus making seriously concerned about the infrastructure objects technical condition observation and control at different life-cycle levels.
Having synthesized more than 20 years experience of continuous hazardous production monitoring and diagnostics for petrochemical, metallurgical and mining industries, as well as experience of railway equipment diagnostics, DYNAMICS SPC develops actively the innovative technology of rolling-stock equipment technical state control, based on real-time condition monitoring - automated control system for safe-money-saving proactive maintenance COMPACS® - ACS SMSPM™ COMPACS®.
ACS SMSPM™ COMPACS® principal components are means of monitoring, diagnostics and integration:
systems for EMUs assemblies and units diagnostics at acceptance tests areas of workshops TR-2, TR-3 (COMPACS®-EXPRESS, COMPACS®-AGREGAT, COMPACS®-RPP);
systems for comprehensive diagnostics of EMUs sections at acceptance tests areas of workshops TR-2, TR-3 (COMPACS®-EXPRESS-TR3);
on-board systems for EMUs equipment technical condition monitoring (COMPACS®-EXPRESS-3);
diagnostic network Compacs-Net®, which unites monitoring and diagnostic systems and provides data submission to different operation and repair control levels.
In order to simplify the maintenance and technical support processes, all ACS SMSPM™ COMPACS® systems are built up on the base of common hardware and software, have a built-in function of sensors autodiagnostics and a general metrological base, including measuring channels verification/calibration methods.
An important feature of COMPACS® systems is a possibility of integration to the diagnostic network Compacs-Net®, implemented at the enterprise. Owing to Compacs-Net® the objective evidence about technical condition is available in real-time for the enterprise chiefs and actionees.
Looking ahead the means of control and diagnostics can be connected to Compacs-Net®, being located at the enterprises-manufacturers of componentry and equipment for rolling-stock and the infrastructure objects. This will allow to create a common information-diagnostic space for the effective technical condition control of railcar rolling-stock.
Kostyukov V.N. Innovative technologies of electric trains operation // Daily transport newspaper "Gudok". - 2012. - 12 July. - № 119 (25080)
The necessary completeness and depth of electric circuits diagnostics can be provided by means of resistance assessment of control circuits loops under consideration and high-voltage power and auxiliary circuits sections. Obviously, the current sensors mounting at each loop of control circuits is inexpedient, as in that case the diagnostic complex complication exceeds the diagnosed object complication in several times.
To determine the specified parameters with the minimal number of sensors and the diagnostic complex flow lines, a principle of control circuits functional-test diagnostics has been developed. The principle consists in determining of each branch diagnostic features through timely inclusion of the branch in the operational process. This inclusion is carried out by means of test impacts injection to the main and auxiliary inputs. The specific sequence of impacts makes them identical to working ones.
At the same time the high-voltage circuits switching units fulfill the assigned functions in the whole range of possible combinations. The use of additional inputs (impacts injection has not been foreseen by the operation working algorithm for these impacts) for test impacts injection even with functional impairment in the branches of control circuits, corresponding to the main inputs, allows to ensure the impact transfer to the actuator, thus performing their primary function.
Kostyukov Al.V., Kazarin D.V. The choice of diagnostic features for electric trains circuits // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 189-194
Diagnostics of the rolling stock wheel-motor units is an urgent matter of today. Bearing assemblies of wheel-sets and wheel-motor units (WMUs) undergo enormous impact forces and their technical condition largely influences a train performance safety.
It is customary to use 6 vibration sensors which are mounted on the general bearing assemblies (axle bearings, reducer, traction motor). Nevertheless there is an opinion that such a number of sensors is abundant and only increases diagnostic operations time.
In order to determine capability of vibration sensors number reduction while diagnosing of an electric train wheel-motor units, studies on the mutual impact between different subjects diagnostic features have been carried out.
Zaycev А.V., Lagaev А.А., Kostyukov V.N. Capability determination of vibration sensors number reduction while diagnosing of an electric train wheel-motor units // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 154-157
Operating safety level of units with piston compressors is determined by reliability of their technical condition monitoring, timeliness and accuracy of malfunctions and their causes detection. Nowadays there are numerous technical tools designed for piston compressors monitoring and diagnostics, which are developed and manufactured in different countries by various companies. However, it remains a pending issue if the measurements are adequate to the actual technical condition of piston compressors and to the risk magnitude of their safe operation. Although there is a document that defines the general requirements for critical industrial facilities monitoring systems, nevertheless even experts find it rather difficult to sort out the advertised systems capabilities. In this connection there is an urgent necessity to systematize the condition diagnosing and monitoring methods and means for piston compressors.
Almost all monitoring and diagnostic systems are characterized by:
determination methodology for technical condition of piston compressors units and components is based on measurement of direct structural and technological parameters (relative displacement, pressure, temperature) and implements an online technology;
expert systems use the values of direct structural and technological parameters;
parameters of indirect processes (vibroacoustic oscillations) are used to assess these parameters values without a diagnosis-making and detection of malfunctions and defects causes.
In the equipment vibration analysis system COMPACS® the methodology for real-time monitoring and diagnostics is based not only on the measurement of direct structural and technological parameters, but on the use of vibroacoustic oscillation parameters as well, there have been implemented algorithms of the expert decision support system with an autodetection (in the rate of diagnostic signals measurement) of more than 20 units malfunctions and defects and the degree of their danger.
Naumenko A.P. Analysis of modern methods and means of piston compressors condition monitoring and diagnostics // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 107-115
EMUs electrical circuits are divided into low-voltage control circuits, high voltage power and auxiliary circuits and in general constitute a complex, multi-element, multiply object with feedback loops and a large number of parameters, and its reliable operation has a significant influence upon the security and uninterrupted functioning of the railway carryover conveyor.
A repair system, designed to maintain an acceptable reliability level of rolling-stock and based on the scheduled preventive principle, has already exhausted its resource of cheap, skilled labor force and is not currently able to provide a high level of safety, keeping to schedule and improving the transportation process quality while reducing costs. Lack of modern and reliable devices for technical condition monitoring is the main reason of EMUs defects and failures. According to the statistical accounting of «Russian railways» JSC, about 60% of these defects and failures occur in electrical circuits.
Achievement of a high efficiency and reliability in the technical condition assessment of complex objects is possible on the basis of technical diagnostics devices, which development and implementation is preceded by phases of the object study and the diagnostic algorithms synthesis.
Electrical circuits can be represented as a single discrete logic device, whose input, internal and output signals have two stable states, respectively, and for their analysis it is advisable to use the mathematical apparatus of logical algebra.
Kazarin D.V. Synthesis of algorithms for diagnostics of electric circuits // Omsk Research Journal. - 2009. - pp. 133-135
Serviceability and performance capacity of repaired equipment is not objectively a guarantee of its correct operation as a part of this or that electric multiple unit system. Relationship between the elements, devices and units can be broken as a result of installation defects, damage can appear while transportation, assembling and subsequent debugging. The defects appearance at this stage of the technological cycle leads not only to duration increase of EMU putting into operation (debugging period), but, in the case of a defect omission, to spoilage and failures on the line.
Improving the quality of the motor driven rolling stock with a simultaneous reducing of debugging duration and complexity is possible on the basis of automated systems for comprehensive diagnostics of repair and assembling quality of the most complex and critical EMUs systems that provide a reliable quantitative and qualitative assessment of their technical condition, in accordance with the guidelines requirements.
The article presents some results concerning development and application of systems for comprehensive diagnostics of EMUs repair and assembling quality. EMUs are widely used at enterprises of «Russian Railways» JSC and at factories which are prospective for the railway industry being a means of improving reliability, maximizing EMUs exploitation with a simultaneous reducing of costs for repairs and speedy reconstruction of repair system on safe resource-saving basis.
Kostyukov V.N., Kostyukov Al.V., Kazarin D.V. Quality diagnostics of electric circuits assembling // Assembling in mechanical engineering, instrument making. - 2009. - № 12. - pp. 25-34
Design life of rolling bearings is determined by bearing capacity rating, equivalent load and bearing type (ball or roller). The equivalent load is determined by two factors: static and dynamic.
If the static load is determined by the machine operation mode and can vary within wide limits, the dynamic load is determined by the bearing state - all the roughness and defects in rolling elements and surfaces lead to an increase in dynamic forces affecting the bearing, and as a result, reduce its life. Besides, this decrease in life can be rather significant. Thus, for bearings with spoilage in production, when static and dynamic forces are comparable, the design life drops to 8 times for ball bearings and 10 times for roller ones. This explains the necessity for carrying out rolling bearings input vibration analysis before they are installed on the repaired or re-manufactured machines.
The article shows a dependence diagram of the bearing velocity overall level from the magnitude of the applied radial static load. It has been concluded that when measuring the bearing vibration parameters, we can judge about the magnitude of dynamic forces affecting the bearing, and thus we can more accurately evaluate its potential life.
Solution to the problem of purchased bearings 100% acceptance testing is the application of vibration analysis methods, where through the analysis of vibration signal one can quickly give an opinion on the bearing state without disassembling and micromeasuring. To solve this problem the benchtop system COMPACS®-RPP has been developed.
Kostyukov V.N., Boychenko S.N., Kostyukov A.V., Molteninov A.V., Buluchevsky Yu.V., Karpov S.Yu.,Dvukhzhilov D.V. , Shchelkanov A.V. Benchtop system for rolling bearings acceptance vibration analysis // Assembling in mechanical engineering, instrument making. - 2009. - № 4. - pp. 38-42
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