• Journal of Electrical Engineering and Technology
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• 제2권4호
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• pp.485-493
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• 2007

This paper deals with the problem of detection of induction motor incipient faults. Artificial Neural Network (ANN) approach is applied to detect two types of incipient faults (1). Interturn insulation and (2) Bearing wear faults in single-phase induction motor. The experimental data for five measurable parameters (motor intake current, rotor speed, winding temperature, bearing temperature and the noise) is generated in the laboratory on specially designed single-phase induction motor. Initially, the performance is tested with two inputs i.e. motor intake current and rotor speed, later the remaining three input parameters (winding temperature, bearing temperature and the noise) were added sequentially. Depending upon input parameters, the four ANN based fault detectors are developed. The training and testing results of these detectors are illustrated. It is found that the fault detection accuracy is improved with the addition of input parameters.

• Tribology and Lubricants
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• 제23권1호
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• pp.1-8
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• 2007

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed to overcome the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. Therefore, in this study, the effects of the type of inlet oil port, inlet temperature and the sort of engine oil on the performance of a turbocharger bearing are to be investigated. It is found that the type of oil inlet ports, the control of inlet oil temperature and the selection of engine oil type play important roles in determining the temperature and pressure, then the friction and load of a turbocharger journal bearing at high speed operation.

• 드라이브 ㆍ 컨트롤
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• 제10권1호
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• pp.14-20
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• 2013

In the high rotational speed and pressure state, the leakage flow rate of the axial piston pump is one of the serious problems and make great reasons to decrease the volume efficiency. In this study, tribology characteristics is clarified for the hydrostatic slipper bearing in the swash plate type axial piston pump, by means of theoretical analysis for the different shape of the hydrostatic slipper bearing. It was analyzed by Mathcad software and used equal conditions at $0^{\circ}$ swash plate angle in each model. The results show that performance characteristics of the swash plate type axial piston pump are significantly influenced by the shape of the hydrostatic slipper bearing.

• 대한기계학회논문집
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• 제19권2호
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• pp.313-321
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• 1995

The effects of the temperature rise and the turbulence are very important factors to predict the accurate performance of a large tilting pad journal bearing. In this study, the dynamic characteristics of a large tilting pad journal bearing are analyzed, taking into account the three dimensional variation of lubricant viscosity and turbulence. The effects of the temperature rise and the turbulence on the stiffness and damping coefficients are investigated in comparison with the results from the laminar or isothermal theory. The stiffness and damping coefficients increase due to the turbulence but decrease due to the temperature rise. The results show that the effects of both the temperature rise and turbulence must be considered simultaneously in order to predict the dynamic characteristics of a large tilting pad journal bearing more accurately.

• Steel and Composite Structures
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• 제27권3호
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• pp.285-295
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• 2018

In this paper, the bearing capacity of a non-eccentric and eccentric tubular, concrete-filled, steel bridge pier was studied through the finite element method. Firstly, to verify the validity of the numerical analysis, the finite element analysis of four steel tube columns with concrete in-fill was carried out under eccentric loading and horizontal cyclic loading. The analytical results were compared with experimental data. Secondly, the effects of the eccentricity of the vertical loading on the seismic performance of these eccentrically loaded steel tubular bridge piers were considered. According to the simulated results, with increasing eccentricity ratio, the bearing capacity on the eccentric side of a steel tubular bridge pier (with concrete in-fill) is greatly reduced, while the capacity on the opposite side is improved. Moreover, an empirical formula was proposed to describe the bearing capacity of such bridge piers under non-eccentric and eccentric load. This will provide theoretical evidence for the seismic design of the eccentrically loaded steel tubular bridge piers with concrete in-fill.

• 한국안전학회지
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• 제12권1호
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• pp.9-18
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• 1997

This paper is a study on the dynamic characteristics of truncated cone type squeeze film damper(SFD) bearing and rotor system. This model can alter the radial oil film gap which Is Important to the performance of rotor-bearing system and manufactured easily to change the shape concept of traditional circular type SFD bearing. In theoretical analysis, the oil film pressure distribution, the oil film force, the film damping coefficient and the eccentricity ratio, etc. were induced with regard to the film inertia effect. The film damping coefficients and optimum design parameters are calculated. When unbalance parameter U is greater than 0.2, the nonlinear vibration such as "Jump" phenomena appears in the vicinity of rotor critical speed. At this time, the increases of bearing parameter U, journal distance S, Reynolds number Re can control this unstable vibration. The experimental results show that SFD hearing and rotor system which are designed according to the design parameters in the stable region are operated stably in rotational speed 9,600rpm without nonsynchronous behavior.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.425-431
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• 1999

Nowadays development of electric and optical devices needs precision more and more. This study focuses on hydrostatic journal bearing of grinding wheel spindle. It presents theoretical analysis about cylinder type self-controlled restrictor to control flux of oil flowing into pockets around the hydrostatic journal bearing. As a result of this analysis, optimal properties to maximize bearing stiffness such as initial cross distance, supply pressure, diameter of two supply holes, pre-load of spring and clearance between spindle and housing can be obtained. Therefore, by using them it is possible to estimate bearing stiffness and the performance of grinding wheel spindle can be improved.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.36-41
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• 2004

The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL's EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.

• 대한기계학회논문집A
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• 제25권2호
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• pp.198-205
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• 2001

Recently, almost all hard disk drives employ the rotary actuator system. The performance of an HDD depends on the accuracy and speed of tracking motion. We study the dynamics of head-suspension assembly during track seek. We develop the numerical analysis program to study the dynamic characteristics of HDD suspension system considering the air bearing effects. The track seek simulation by using the developed program helps to estimate the effect of the suspension vibration on the air bearing dynamics. We calculate the behaviour of the air bearing for the given track seek profile and calculate the positioning error during track seek process due to the lateral deflection of the suspension.

• 한국자동차공학회논문집
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• 제12권4호
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• pp.34-34
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• 2004

The purpose of this paper is analyzing the oil film pressure distribution and the minimum oil film thickness for a connecting rod bearing using an A VL′s EXCITE program. It is very important to understand optimized oil supplying holes and oil groove dimensions for supporting sufficiently inertia forces and gas pressures from the combustion chamber for a Diesel engine. The computed results indicate that the optimized oil groove width of a bearing and oil hole of a journal are recommended for high performance of a connecting rod bearing at the elastohydrodynamic lubrication zone. These results as design parameters are very useful data for a bearing designer as a firm reference of an automotive engine.