• 전기의세계
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• v.28 no.11
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• pp.14-25
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• 1979

Thyristor inverter로 구동되는 동기전동기의 특성 해석을 직류기로서 취급하기 위하여 등가회로로 유도하였고 브러쉬축및 이에 직교하는 축인 .gamma.축 및 .delta.축의 전압 $v_{\gamma}$, $v_{\delta}$에 평골전원과 맥동전원이 인가될 경우 각각의 동기전동기의 특성변화를 구하였다. 그 결과 맥동전압으로 인한 전자기 권선에 흐르는 고주파전류는 인가전원 주파수에 6배되는 진동토오크가 발생함을 알 수 있었다. 이 맥동토오크의 평균치는 정현파 전원 구동시와 거의 동일하게 되나 전동기의 관성 크기에 따라 난조현상에 미치는 영향을 고려해야 할 것으로 나타났다. 끝으로 120 .deg. 유통형 및 180 .deg. 유통형 inverter구동에 따른 동기전동기의 토오크 특성이 각각 타여자 직류전동기 특성및 정출력 특성이 됨을 밝혀내었다.었다.었다.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.1
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• pp.40-49
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• 2000

In this paper, an empirical formula to estimate the steering gear torque of a Tanker with a horn type rudder was developed by using the statistical analysis. The hydrodynamic characteristics of the horn type rudder in the free-stream condition were calculated by using the modified lifting line theory by Molland, and the interaction effects by propeller and hull were analyzed by the regression analysis of the sea-trial data of 32 vessels. The comparison with the delivered vessels' data shows that the formula can be used for predicting the steering gear torque at the initial design stage.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.28-33
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• 2004

Generally Horn-type rudders have been used for single propeller and single rudder system. The reason is that the rudder torques of Horn-type rudder are smaller than those of Spade rudder with same lift force. But it is found that the rudder cavitation occurs on a Horn-type rudder of fast container ship. In this paper the comparison results of Horn-type and Spade rudders are described. HPMM tests are carried out to compare the effects of two rudder types on the maneuverability of a ship. It is shown that the maneuvering performance of a ship equipped with Horn-type rudder is better than that equipped with Spade rudder by comparing the test results and maneuvering coefficients at scantling condition. The reason is that the movable part area of Horn-type rudder is about 14％ larger than that of Spade rudder with same total area. And the rudder torque of Spade rudder is greater than that of Horn rudder. At ballast condition, however, the effect of rudder type is negligible.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.194-201
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• 2000

It is called vehicle pull when a vehicle drifts in the lateral direction under the straight-ahead motion with no steering or external input. Recently vehicle pull draws attention as one of the critical evaluation items from the customers on the vehicle quality. It is generally recognized that the vehicle pull is complex phenomena due to internal and external factors. In this paper the relations between vehicle pull and ire were investigated through close survey on the road test results from the final inspection of car manufactures. Through this investigation the factors are identified which play an important role in causing vehicle pull problem.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.5
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• pp.157-164
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• 2000

It is known that residual aligning torque of tires causes vehicle pull. There is, however, only a little literature available which shows how the residual aligning torque of tires causes vehicle pull. In this paper, a vehicle model in two degrees of freedom was adopted for the analysis of a vehicle under the straight-ahead motion. The analysis with this vehicle model clearly shows the effect of residual aligning torque of tires on vehicle pull. In order to show the validity of the analysis, a vehicle commercially available was selected. This vehicle was modeled in 137 degrees of freedom system with multibody dynamics software. Vehicle pull simulation results show that vehicle model drifts in lateral direction due to the residual aligning torque of tires. Vehicle test results with the car were also included.