• Journal of Power Electronics
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• v.12 no.1
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• pp.208-214
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• 2012

This paper presents a novel approach based on the loci of instantaneous symmetrical components called "Wing Shape" which requires the measurement of three input stator currents and voltages to diagnose interturn insulation faults in three phase induction motors operating under different loading conditions. In this methodology, the effect of unbalanced supply conditions, constructional imbalances and measurement errors are also investigated. The sizes of the wings determine the loading on the motor and the travel of the wings while their areas determine the degree of severity of the faults. This approach is also applied to detect open circuit faults or single phasing conditions in induction motors. In order to validate this method, experimental results are presented for a 5 hp squirrel cage induction motor. The proposed technique helps improve the reliability, efficiency, and safety of the motor system and industrial plant. It also allows maintenance to be performed in a more efficient manner, since the course of action can be determined based on the type and severity of the fault.

• Journal of Applied Reliability
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• v.12 no.2
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• pp.79-90
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• 2012

The torsion beam type of rear suspension has been adopted by most manufactures of small to medium front wheel drive passenger cars. Previous studies analyzed only the load characteristics of CTBA(the coupled torsion beam axle)'s components. This paper analyzed the results of measurement after measuring loads and displacements, angles when a car equipped with the coupled torsion beam axle is driving in various roads. The most important durability factors for CTBA part are the force and direction of rear CTBA trailing arm. If there are design changes, it was difficult to make a sensor and install each time for measuring the trailing arm forces. After analyzing the loading histories between body and chassis, we developed the transformation matrix that can be converted to mutual force. This paper also deals with the analysis of the force behavior through the analysis of the influence and correlation between the body and chassis parts of cars.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.315-325
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• 2018

This paper investigates optimum air-gap flux distribution with third harmonic rotor flux orientation adjustment for five-phase induction motor. The technique of objective is to generate a nearly rectangular air-gap flux, and it improves iron utilization under variation loading conditions. The proportional relations between third harmonic and fundamental plane currents is usually adopted in the conventional method. However, misalignment between fundamental and third harmonic component occurs with variation loading. The iron of stator teeth is saturated due to this misalignment. This problem is solved by third harmonic rotor flux orientation adjustment simultaneously, and direction and amplitude are changed with mechanical load variation. The proposed method ensures that the air-gap flux density is near rectangular for a maximum value from no load to rated load. It is confirmed that the proposed method guarantees complete both planes decoupling with third harmonic flux orientation adjustment. The effectiveness of the proposed technique is validated experimentally.

• Proceedings of the Korean Nuclear Society Conference
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• 2002.10a
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• pp.93-93
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• 2002

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.55-58
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• 1995

An optimum design method of electric machines using neural network is presented. In this method, two multi - layer perceptrons of analysis and design neural network are used in optimizing process. A preliminary model of linear induction motor for subway is designed by the electric and magnetic loading distribution method and then optimized by presented method.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1928-1934
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• 2014

Induction motors are widely used due to their rugged, robust and easy to care features. Since they are heavily used in industry, testing of three phase induction motors have play a vital role. In order to determine motor equivalent circuit parameters, efficiency of motor, squirrel caged laboratory sized an induction motor test setup is prepared. It is suitable for the induction motor with the frame size of 100 and 112. A virtual Instrumentation typed engineering workbench (called as LabVIEW) software packet, is utilized as a graphical user interface program. Motor input power is measured by measuring the input voltage, current and power factor with the help of hall effect typed voltage and current transformers. Also, the output power is measured by measuring the speed and torque with the help of an encoder and torque sensor. All outputs of the voltage and current transformer, encoder and temperature, torque sensors are given to the Data Acquisition Card (DAQ) which acquires the data for processing and then the equivalent circuit parameters, efficiency, performance and loading characteristics are found out, using LabVIEW based user interface. It is suggested to use this test rig for the quality control of produced motors in industry, and an educational experiment setup in the school laboratories.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.12
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• pp.999-1005
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• 2016

A brushless direct current (BLDC) motor electronically performs rectification without brushes. It therefore does not have the typical mechanical friction contacts between the brushes and commutators. The BLDC motor has the advantages of high speed, low noise, and electronic noise reduction in addition to high durability and reliability. Therefore, it is mainly used in electric vehicles and electric equipment. However, iron loss and copper loss due to long-term use induce temperature increases in the motor, which reduces its performance and life. The temperatures of the stator and permanent magnet are predicted to be $62.3^{\circ}C$ and $32.2^{\circ}C$, respectively. This study shows the enhanced temperature distribution in a 600 W BLDC motor using unsteady and three-dimensional (3D) numerical investigations validated with experimental data.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.64-71
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• 2006

In this paper, a uniform speed controller for an ultrasonic rotary motor is developed using the phase-difference method. The phase difference method uses traveling waves to drive the ultrasonic motor. The traveling waves are obtained by adding two standing waves that have a different phase to each other. A compact phase-difference driver system is designed and integrated by combining VCO(Voltage Controlled Oscillator) and phase shifter. Theoretically the relationship between the phase difference in time and the rotational speed of the ultrasonic motor is sine function, which is verified by experiments. Then a series of experiments under various loading conditions are conducted to characterize the motor's performance that is the relationship between the speed and torque. Proportional-integral control is adopted for the uniform speed control. The proportional control unit calculates the compensating phase-difference using the rotating speed which is measured by an encoder and fed back. Integral control is used to eliminate steady-state errors. Differential control for reducing overshoot is not used since the response of ultrasonic motor is prompt due to its low inertia and friction-driving characteristics. The developed controller demonstrates reasonable performance overcoming disturbing torque and the changes in material properties due to continuous usage.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.406-408
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• 1996

This paper describes the BLDC motor which is applicated for a top front loading domestic washing machine. This motor is adopted direct drive washing machine without gear-belt-pulley system. Because gear box is removed, machine volume and noise are reduced. Moreover mechanical troubles in gear box are removed. Realization of variable speed region through of PWM control and high speed is able to efficient washing and spinning.

• Journal of Power Electronics
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• v.1 no.1
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• pp.19-25
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• 2001

A high speed, three phase, 12/8 pole, 225 kW switched reluctance motor (SRM) has been designed and analyzed. A circuital approach has been used to find the geometry, windings parameters and electromagnetic loading. Then, the 3D finite element method (FEM) has been used to calculate the static torque more accurately and optimize the design. The efficiency of the designed SRM is almost constant over wide range of speed and its phase current is less sensitive to the speed than that of an induction motor of the same rating. Recommendations for manufacturers and users are given.