Classification of the operating state of rolling bearings with the convolutional neural network with variable dilation factors

The work describes rolling bearings operation data processing, and their use in the problem of constructing a mathematical model of the binary classification of the operating state of bearings by the method of a convolutional neural network with varying factors of dilatation of the kernel of convolutional layers. To classify bearings with defects, we used vibration acceleration data from our own test bench and a publicly available data set. The work also investigated a method for generalizing the classification of bearing signals obtained as a result of fundamentally different experiments and having different standard sizes. To unify signals, the following processing method is proposed: select data areas with displacement, go to the frequency space using fast Fourier transform, cut off frequencies exceeding 10 times the shaft rotation frequency, restore the signal while maintaining 10 shaft rotation periods, scale the received signal by dividing it by its diameter orbits of the rolling body and interpolate the signal at 2048 points. This algorithm also allows to generate a balanced sample for building a mathematical model. This feature is provided by varying the step of splitting the initial signal. The advantage of this algorithm over the classical methods of oversampling or undersampling is the generation of new objects that specify the statistical parameters of the general population. The signal processing algorithm was used both for binary classification problems within one dataset, and for training on one and testing on another. To increase the data set for training and testing the mathematical model, the bootstrapping method is used, based on multiple generation of samples using the Monte Carlo method. The quality of the mathematical model of binary classification was assessed by the proportion of correct answers. The problem is formulated as the problem of minimizing binary cross entropy. The results obtained are presented in the form of graphs demonstrating the neural network training process and graphs of the distribution density of metrics.

Large Eddy Simulation of Leakage Flow in a Stepped Labyrinth Seal

Large eddy simulation (LES) and Reynolds averaged Navier-Stokes simulation (RANS) of leakage flow in straight-through and stepped labyrinth seals were performed in order to compare their performances in sealing the secondary flow passage of the gas turbine based on the respective discharge coefficients. The results indicate a 17.8% higher leakage prevention performance for the stepped seal relative to that of the straight seal. Further, while the LES predicts an ~7% reduction in the discharge coefficient due to shaft rotation, this effect is underestimated by the RANS. Moreover, the LES correctly predicts a laminarized flow pattern in the clearance, whereas the RANS overestimates the turbulence kinetic energy. In addition, a turbulence kinetic energy spectrum analysis was performed based on the vorticity at selected points in order to identify the flow structure that has a dominant influence on the oscillation of the discharge coefficient. This analysis also enabled identification of the changes in the flow structure due to shaft rotation.

Determining an additional diagnostic parameter for improving the accuracy of assessment of the condition of stator windings in an induction motor

This paper has proposed and substantiated the application of an additional diagnostic parameter for assessing the state of stator windings of induction motors during operation. The dependences of the values of phase shifts between phase currents and phase voltages have been obtained. These dependences showed that when an inter-turn short circuit occurs in the stator windings, the phase shifts are the same for all phases of the motor. That has made it possible to obtain the dependence of the change in phase shift on the change in the engine shaft rotation frequency. This study's result has established the dependence of the rates of change of the phase angle on the engine shaft rotation frequency for both one and two damaged phases with varying degrees of damage. When analyzing these dependences, it was found that with an increase in the number of damaged phases of the electric motor, the linear section of the dependences decreases. In addition, with an increase in the degree of phase damage, the angle of inclination of the linear sections of the characteristics decreases. That has made it possible to determine an additional parameter for diagnosing the place and degree of an inter-turn short circuit of the windings in an induction motor with a squirrel-cage rotor. The values of the additional parameter, termed by this paper's authors as a "phase criterion" can be used to assess the condition and degree of damage to the stator winding of induction motors. The values of the phase criteria for various types of damage were: when phase A is damaged by 90 %, ξ=0.634, (deg)2/(rpm)2; when phase A is damaged by 80 %, ξ=0.393, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.25, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.173, (deg)2/(rpm)2. The results of this research could be used to select an effective method for diagnosing an inter-turn short circuit in the stator winding when building a diagnostic system for induction motors as part of drives of transport equipment

Study of Interconnected Physical Processes in the Magnetic Fluid Sealer

The purpose of this work is creation of an interconnected numerical model of the magnetic and hydrodynamic fields of the ferrofluid sealer to analyze the effect of centrifugal forces during shaft rotation on the retained pressure drop. The set goal was achieved by selection of the necessary equations, boundary conditions, assumptions and properties concerning the ferrofluids when building a numerical model of the sealer gap in the Comsol Multiphysics simulation environment. The important results of the work were the obtained and analyzed distributions of the magnetic field and pressure field in the ferrofluid, the evaluation results of the of the effect of centrifugal forces arising during the shaft rotation, on the pressure drop held by the sealer. It was shown that with a shaft radius of up to 50 mm and speed up to 3000 rpm, the change in the retained pressure drop was insignificant, and it was up to 2 % of the values with a stationary shaft. Significant manifestation of centrifugal force for the investigated shaft radii began at 6000 rpm. It was shown that the decrease in the retained pressure drop with an increase in the working gap was associated with the decrease in the magnetic field gradient. The significance of the results consisted in the possibility of using the developed model for the study of the ferrofluid sealer gap processes. Comparison with the data obtained using the analytical formulas showed that the latter overestimated the retained pressure drop

Analysis of Airconditioning System Using Single-Rotor Wind Turbine Power, Dual Rotor Wind Turbine Power, and Ducted Dual Rotor Wind Turbine Power As Input to Compressor

As vapor compression refrigeration system is the best-suited system used in the present scenario due to its various advantages, in the present paper MATLAB analysis is done for the analysis of simple VCR to calculate COP and refrigeration effect.in the present paper R134a refrigerant is used as a refrigerant.as we know a certain amount of power is used to drive the compressor input in conventional VCR system uses electrical power to convert into mechanical shaft rotation with certain rotation, power and torque.in this paper specific power torque and rotation is given to the compressor without any electrical motor. the power obtains from an SRWT, DRWT, and DDRWT with specific torque power and rotation. then after analysis is carried out to get the COP and Refrigeration Effect.

Effect Of Rotor Blade Wing Tip On Wind Turbine Performance Using Naca 0018 Blade

Indonesia currently has a growing need for energy, this will experience an energy crisis, dependence on fossil fuels will at least have a serious threat, therefore there must be alternative energy as a substitute and reserve such as wind energy, water energy, solar energy, and other. This study aims to develop a wind power plant as an alternative source to produce electrical energy, namely a wind turbine. This tool is used to meet energy needs and also as an alternative energy so that fossil fuels will not run out. Because Indonesia is an archipelagic country and is located on the equator, Indonesia is a country that has abundant resources, one of which is wind. Wind turbine is a tool that functions to convert wind power into mechanical power in the form of a shaft rotation, this shaft rotation is then used for power generation or for water pumps. Therefore I tried to develop my ideas to utilize abundant natural resources to be used as a source of electrical energy by means of a wind turbine using a Naca 0018 blade. This study aims to determine the effect of the number of blades, the effect of profiles, the effect of the wing tip of the rotor blades. , naca 0018, and the resulting energy efficiency. This study uses the type of experimental research.

Laboratory Scale of Seed Damage of Coarse-Grain Depending on Groove Diameter and Depth in Roller Devices

HighlightsThe rate of damage to the bean seed by the grooved roller planter was determinedThe effects of planting speed, seed rate, groove diameter, and groove depth on seed damageThe most suitable groove diameter and depth were determined in bean plantingAbstract. Grooved roller planters can be used in the planting of small and large seeds when they are produced in the appropriate groove diameter and groove depth depending on the seed dimensions. In this study, the rate of damage to the dry bean seeds of the grooved roller device, which was modified and placed on the bottom of the warehouse of a grain planter, was investigated. Nine grooved rollers manufactured in different groove diameters (18, 20, and 22 mm) and groove depths (5, 8, and 11 mm) were tested at 80, 120, and 160 kg ha-1 seed rates and 8, 13, and 18 min-1 feed shaft rotation speeds. Breakage, crushing, and cracking in dry bean seeds were considered as damaged seeds. According to the results, the increase in the seed rate, feed shaft rotation speed, and groove depth reduced the seed damage rate. The increase in groove diameter increased the rate of seed damage. The lowest seed damage rate values were obtained at 160 kg ha-1 seed rate, 2 m s-1 forward speed, 18 mm groove diameter, and 11 mm groove depth. Keywords: Active groove length, Dry bean seed, Forward speed, Grooved roller, Seed rate.

Mathematical modeling of centrifugal machines rotors seals for the purpose of assessing their influence on dynamic characteristics

With an increase of equipment parameters, such as the pressure of the sealing medium and the speed of shaft rotation, the problems ensuring its hermetization efficiency are rising up. In addition to hermetization itself, the sealing system affect the overall operational safety of the equipment, especially vibratory. Groove seals are considered as hydrostatodynamic supports capable of effectively damping rotor oscillations. To determine the dynamic characteristics, models of grooved seals and single-disc rotors with grooved seals are examined. The obtained analytical dependences for computation of dynamic characteristics for the hydromechanical rotor-seals system, describing radial-angular oscillations of the centrifugal machine rotor in groove seals are presented as well as the formulas for computation of amplitude frequency characteristics. An example for the computation dynamic characteristics of one of the centrifugal machine rotor models is drawn.

PERANCANGAN SISTEM TRANSMISI PADA MESIN PENCACAH LIMBAH PLASTIK TIPE SHREDDER

In making plastic waste machine shredder, it is necessary to design the transmission system, with the goal of making it easier to make the output needed to the community, especially in household production. The transmission system used in shredder machines is to use a reducer gearbox which will be distributed on the drive shaft. In order for the transmission to be calculated as expected, enough power is needed to drive the machine. In this case, of course, special calculations are needed to find accurate data so that the shredder machine can work as expected. Power on electric motors, of course, there are many types on the market. In the end, it is necessary to determine the specifications of the electric motor which is suitable for this shredder machine. The transmission system is obtained from the results of precise calculations and analysis to produce output for shaft rotation. The transmission system or commonly referred to as the gearbox must determine the ratio which will produce the expected output rotation. Based on the analysis of the planning and calculations that have been carried out on this shredder type plastic waste chopping machine with reference to the research objectives, the power data required for the shredder type plastic waste chopping machine is 1.3 kW so a motor with a capacity of 1.5 kW is needed. The rotation of the motor takes 1400 rpm with a 1:20 gearbox (reducer) to produce an output of 70 rpm which is then distributed through the sprocket and chain with a 1: 2 ratio by producing an output rotation of the blade shaft of 35 rpm. And the transmission system on this machine uses a chain and sprocketPada pembuatan mesin pencacah limbah plastik diperlukan adanya perancangan pada sistem transmisinya, dengan tujuan agar memudahkan dalam membuat output yang dibutuhkan di masyarakat khususnya pada produksi rumah tangga. Pada sistem transmisi yang digunakan pada mesin pencacah adalah dengan menggunakan gearbox reducer yang nantinya akan didistrbusikan pada poros penggerak. Agar transmisinya dapat dihitung sesuai dengan yang diharapkan diperlukan daya yang cukup untuk menggerakan mesin tersebut. Dalam hal ini tentunya diperlukan perhitungan khusus untuk mencari data yang akurat agar mesin pencacah tersebut dapat bekerja dengan yang diharapkan. Daya pada motor listrik tentunya banyak jenis-jenis yang ada di pasaran. Pada akhirnya diharuskan untuk menentukan spesifikasi motor listrik yang cocok untuk diterapkan pada mesin pencacah plastik ini. Sistem transmisi didapatkan dari hasil perhitungan dan analisa yang tepat sehingga menghasilkan output untuk putaran poros. Sistem transmisi atau biasa disebut dengan gearbox harus ditentukan perbandingan yang nantinya akan mengeluarkan putaran output yang diharapkan. Berdasarkan dari analisa perencanaan dan perhitungan yang telah dilakukan pada mesin pencacah limbah plastik tipe shredder ini dengan merujuk pada tujuan penelitian, dapat diambil data daya yang dibutuhkan untuk mesin pencacah limbah plastik tipe shredder adalah 1.3 kW jadi diperlukan motor yang kapasitas 1,5 kW. Putaran pada motor dibutuhkan 1400 rpm dengan gearbox (reducer) 1:20 sehingga menghasilkan output 70 rpm yang kemudian didistribusikan melalui sproket dan rantai dengan rasio 1:2 dengan menghasilkan putaran output pada poros pisau sebesar 35 rpm. Dan sistem transmisi pada mesin ini menggunakan rantai dan sproket.