• The Journal of the Acoustical Society of Korea
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• v.15 no.4E
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• pp.37-44
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• 1996

To get accurate vibration analysis of rotor-bearing systems, finite element models of high speed rotating shaft, unbalance disk, and fluid film journal bearing are developed. The study includes the effects of rotary inertia, gyroscopic moment, damping, shear deformation, and axial torque in the same model. It does not include the axial force effect, but the extension is straighforward. The finite elements developed can be used in the analysis design of any type of multiple rotor bearing system. To show the accuracy of the models, numerical examples are demonstrated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.1-11
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• 2004

Numerical analyses on the aerodynamic characteristics of a counter rotating axial flow fan were conducted for the development of an axial type in-line duct fan. The counter rotating fan has a front rotor and a rear rotor which are counter rotating each other. Blade design of the counter rotating fan was done by extension of design method for axial flow fan which consists of rotor and stator blades. Through flow analysis was performed using matrix method which is applied for flow fields prediction of compressors or turbines. Aerodynamic characteristics and characteristic curves of the counter rotating fan were analyzed by expansion of the frequency domain panel method with duct modeling. Pressure losses were higher at leading edge and hub region of rotor blades. Characteristic curve of the counter rotating fan was overpredicted without consideration of viscous effect.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.46-48
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• 1998

In this paper, axial type double rotor brushless DC motor is designed where the rotor is located at the both sides of stator. The rotor uses rare-earth magnets of 16 poles and the stator has 12 coils. The genetic algorithm is used to optimize the efficiency of the designed motor. The characteristics of the design parameters are estimated by varying them for the maximum efficiency.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.38-47
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• 2001

One stage axial type turbine is designed by mean-line analysis, streamline curvature method and blade design method using shape parameters. Tip and hub diameter of the turbine are 300mm and 206.4mm, respectively. The rotating speed is 1800RPM, and the output power is 1.4kW. The flow coefficient is 1.68 and the reaction factor at mean-line is 0.373. The number of stator and rotor of the turbine are 31 and 41, respectively. Mach number of stator exit flow near hub is 0.164. A test rig is developed for performance test to validate a developed design method. The experimental result shows that the maximum efficiency is obtained on the design point.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.453-460
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• 2000

A test rig is developed for performance test of 1 stage axial-type turbine which is designed by meanline analysis, streamline curvature method, and blade design method using configuration parameters. The purpose of this study is to find the best configuration parameters for designing a high efficiency axial-type turbine blade. To measure the efficiency of turbine stage, a dynamo-meter is installed. Two different stators which are manufactured as an integrated type are developed, and a rotor blade and 5 sets disc are developed for setting different stagger angle. The tip and hub diameters of the test turbine are 300 and 206.4mm, respectively. The rotating speed is 1800RPM, and the extracted power is 2.5kW. Flow coefficient is 1.68 and the reaction factor at meanline is 0.373. The number of stator and rotor of test turbine are 31 and 41, respectively. The Mach number of stator exit flow near hub is 0.164.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.30-36
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• 2002

This paper presents a developed deep slot squirrel cage induction motor fur the fan. Nearly all of the induction motors consist of two parts, rotor and stator, and the position of rotor is generally inside of stator. However, the rotor of the developed induction motor is located outside of stator. It is believed that the outside rotor type induction motor is suitable for the fan due to its large inertia, that is, it is considered that the change of air flow rate resulting from input power or load fluctuation is reduced. It is considered that the results of this paper can be used for the development of the outside rotor type induction motor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.418-422
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• 2001

This paper presents a developed squired cage induction motor for axial flow fan. The developed squirrel cage induction noter for axial flow fan is exchanged the position, rotor and stater. In this method a fan blade is attached to outside rotor. So we can protect the motor from rain and reduce noise, and there is no need to have bending duct to locate the fan motor. Carried out experimental test with this induction motor, and the results were as follows. Starting torque was 21kgㆍcm@120V, maximum efficiency was 0.84@120V. The characteristics of tests were the same as double squirrel-cage type IM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.559-564
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• 2001

In order to apply into a compact and reliable centrifugal blood pump, this paper introduces a self-bearing motor in which a rotor is rotated without contact. The rotor is actively controlled in only radial directions, while the axial and tilting motions are passively stable owing to the disk-shape structure of the rotor. A prototype was made in outer-rotor type that is far better in the compactness than inner-rotor type. The prototype could be driven up to 8000 rpm with the rotor vibration under 0.12mm. The maximum cardiac output and pressure head were 9 L/min and over 200 mmHg, respectively. These experimental results show that the proposed self-bearing motor has sufficient performance for application to a real blood pump.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.2
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• pp.22-27
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• 2001

Salient pole rotor type single phase switched reluctance motor is of simple and rigid structure, short shaft and simple driving circuit. Especially, the output power per unit volume of salient pole rotor structure is comparatively high because the magnetic fluxes of axial and radial direction are simultaneously used. Therefore, this motor will be used at small space and difficult maintenance situations. In this paper, the selecting method of proper pole arc, stator, and rotor dimension of salient pole rotor type single phase SRM is proposed.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.107-109
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• 2001

The salient pole rotor type single phase SRM has a salient pole in the rotor in order to use axial direction fluxes and radial direction fluxes simultaneously. A flux linkage between the rotor and the stator are increased because of the salient pole in the rotor. But, the inductance at unaligned position and aligned position is increased together. Therefore, the length of pole are and salient pole should be selected that the inductance increment at aligned position is higher than the inductance increment at unaligned position. On this paper, we will be studied the influence of the pole arc and the salient pole length on the torque of the salient pole rotor type single phase SRM.