• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.938-947
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• 2003

In this paper, we derived the formula for estimating the power of the electric motors needed to operate the Decanter-type centrifuge. In the derivation of the formula the sludge-removal torque is to be supplied from the formula derived in the first paper. The intricate nature of the transmission mechanism in the planetary gear trains of the sludge-removal power and torque has been clarified in this second paper. In particular we considered two-motor system, where the main motor drives the machine while the differential-speed control motor plays the role of braking in adjusting the differential speed. Sample calculation for the specific design treated in the first paper showed that the selection criterion for the main motor depends on the lower limit of the differential speed; when the lower limit is set low, it should be selected based on the steadily operating power, while it should be selected based on the starting power when the lower limit is set high. The total power required by both the main motor and the differential-speed control motor increases as the differential speed is decreased. It is suggested that the power loss in the differential-speed control motor could be minimized by attaching an electric generator to it.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.4
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• pp.699-704
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• 2007

In this paper, optimized model was designed for the starting characteristic of the Single-Phase Line-Start Permanent Magnet Synchronous Motor by using the Design of Experiment. A field pole angle, thickness and distance from center axis of permanent magnet were selected as design factor. We executed the transient state characteristic analysis of 8 test models. The transient state characteristic analysis was executed by using the 2 dimensional Finite Element Method and the Time Difference Method. We checked the fact that the selected design factor affected starting characteristic of the Line-Start Permanent Magnet Synchronous Motor. Depend on this result we found the optimized design point by using the response optimization.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.829-832
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• 2010

For gas turbine engine starting, external power should be supplied with engine to accelerate to suitable rotational speed for air and fuel ignition conditions. Electric starting system for small gas turbine engine has simple system and light weight, so it is generally used for small aircraft. For system analysis of gas turbine engine electric starting system, Characteristics of battery, start motor, engine drag torque should be analyzed and theirs temperature effects should be considered. In this paper, preliminary design procedure of small gas turbine engine electric starting system and major design parameters were described.

• 전기의세계
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• v.21 no.3
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• pp.41-47
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• 1972

The requirements of a successful design for single phase induction motors with a high efficiency have, in recent years, led to the use of non-quadrature stator windings motors in which a high starting torque is a prime requisite. The capacitor motor is one of above machines in which various possible forms of asymmetry can be occur. These forms of asymmetry in the stator phase windings, encountered in machine designs, are 1) an asymmetrical disposition in space of their magnetic axes, 2) a difference in their effective number of turns, 3) a difference in the distribution of their coil groups per pole and 4) amounts of capacitance of an auxiary winding. In order to apply the effective performance prediction of these form to motors, mading of lower quality-domestic magnetic materials, the analysis and the experimental investigations of its sample motors are described in this paper. The utility of such a motor is demonstrated and it is shown that the effects- a good efficiency, good power factor and high starting torque-of the motor mechanism with non-quadrature stator phase windings can development disadvantages by using the lower quality-domestis magnetic materials.

• 전기의세계
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• v.23 no.4
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• pp.39-45
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• 1974

In most previous research work, the transverse edge effect has been allowed for only by use of a relativity-increase factor. This paper gives a more exact treatment. A two-dimensional-field analysis is presented for the problem of sheet rotor linear induction motor with finite width the method used takes account of flux leakage in the space between the stator and secondary sheet rotor as well as in the secondary itself. Equations are derived for the flux density distribution in the air gap and for the starting face, in each case as a function of stator current. The cross gap flux density peaks towards athe edge of the stator. This phenomena is known as the transverse edge effect. Measurements of the flux density in the air gap and starting force on a linear induction motor with sheet rotor of different width showed a reasonable agreement,suggest that it would be desirable to take into account also, at least for this motor in which severe redistribution occurs.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.86-88
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• 2005

The line-start permanent magnet synchronous motor has a high efficiency and an advantage in constant speed operation regardless of the effect of load variation. However it is difficult to predict the performance of characteristics accurately, because of the unbalanced starting torque with the initial starting position of the rotor and the generation of a break torque. In this paper the dynamic characteristics of the line-start permanent magnet synchronous motor arc described and compared with those of the squirrel-cage induction motor through the simulation to find the characteristics of the permanent magnets and the rotor bars in the line-start permanent magnet synchronous motor.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.362-364
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• 2001

Every engineering discipline has, in recent year, felt the impact of computer-aided analysis and design Normally the studies of power system analysis by computer are load flow, short circuit and harmonic calculation, the amount the voltage deviates from motor starting, reliability and system stability. These studies are very important from the operating and planning points of power system. This paper presents analysis of load flow, short circuit current calculation, the effect for voltage deviation of induction motor starting and harmonic distortion in power system of continuous casting(C. C) plant. The resulting of analysis is applied the configuration and design engineering of power system.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.324-326
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• 1999

For induction motors cannot maintain constant speed in various speed conditions, synchronous motors are generally used. But synchronous motor oscillate in shocking load, and it cannot start by itself for the lack of starting torque. In this paper, we analyzed the synchronous induction motor which has both characteristics, and compared the experimental results with FEM analysis.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.3-5
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• 2003

This paper deals with the characteristics of a capacitor-run single-phase induction motor by changing of conductor bar numbers. The Finite Element Method (FEM) is used to analyze the starting characteristics according to the rotor initial starting point about conduction bar and the characteristic analysis at the rated condition is calculated by equivalent circuit based on symmetry coordinate theory Finally, the analysis results of the analysis models have different conductor bars in their rotor are compared.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.966-971
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• 2008

Free-piston engine system is a new type energy converter which uses a linear motion of piston by using linear generator. In free-piston engine system, the piston is not connected to a crank-shaft. The major advantages of free-piston engine system are high efficiency and low mechanical loss from the absence of motion conversion devices. Linear generator of free-piston engine system is used as generator and starting motor. In design step, considering of back-emf and detent force characteristics for generating mode and thrust and control characteristics for starting mode is needed. In this research, generating mode of flat-type linear generator and tubular-type linear generator is analyzed by finite element analysis method and starting mode of both type linear generators is analyzed by using capability curve. Capability curve is plotted from electrical parameters of both type linear generator and motion profile is calculated from mechanical parameters.