• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.164-167
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• 2005

In this paper, the design and characteristics of a ${\pi}-shaped$ ultrasonic motor which is applicable to optical zoom operation of lenssystem for mobile phone are investigated. Its desi후 and simulation of performances are carried out by FEM (finite element method) commercial software. As a simulation result, by applying voltage with single phase, a combined vibration is produced at the surface of an arm of stator. The prototype of motor is fabricated and its outer size is 8*4*2 $mm^3$ including the cylindrical steel rod of 2 mm in diameter as rotor. The motor exhibits a maximum speed of 500 rpm and a power consumption of 0.3 W when driven at 20 Vpp and 64 kHz.

• 전기의세계
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• v.16 no.1
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• pp.1-2
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• 1967

The development of the frequency converter using semiconductor enables to easily control the speed of alternating current machineries. In such case, it is desired to observe how several characteristics are changed, such as primary current, power factor, torque, secondary output, efficiency and transient performance. In this paper, the above characteristics are investigated by means of computational method from various constants relating to the motor which is designed in rated frequency 60 cycles. Transient fluctuations in motor speed are also observed with graphical method. These have been validated by the experimental results. When the frequency is to be varied in order to control the speed, it is seen that some of characteristics are getting better and others worse contrarily. The above characteristics may be applied to the optimum electrical, mechanical design of the motor which puts emphases on speed control.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.323-326
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• 1999

In this paper, a windmill type ultrasonic motor operated by single-Phase AC electric field was fabricated, and then torque characteristics were investigated. A metal-ceramic composite component was used as the stator\`s vibrator to generate ultrasonic vibrations. The windmill type ultrasonic motors has only three components; a stator element with two wind-mill shape slotted metal endcaps, a rotor and a bearing. In this parer we measured torque, when stator\`s slot was changed Iron 4, 6, 8. Brass metal was pressed with umbrella-type using metal molt then slot of 3 kind was manufactured. The maximum revolution speed was 388(rpm) in the case of a small ultrasonic motor of 11.35 mm diameter, 8 slot and 1.01 mm thickness. The maximum torque of 0.17 mNm was obtained at a speed of 131 rpm.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.488-493
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• 2005

This paper presents a method of detecting rotor position for single phase Switched Reluctance Motors(SRMs) using a search coil. In the single phase SRM, mainly Hall effect sensors or photo interrupters have been used to detect the rotor position. But these sensors have many disadvantages. In this paper, low cost and robust characteristics of rotor position detection method are focused in order to compensate for disadvantage of existing sensors. Search coils wound around the stator pole are used for detection of the rotor position in single phase SRM. Rotor position detection is achieved through electromotive force patterns induced by time-varying flux linkage in the search coil. The simulation and experimental results are presented to verify the performance of the proposed method in this paper.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.479-483
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• 1997

In general, motor parameters can be divided into mechanical/electrical parameters and harmonic parameters. Mechanical/electrical parameters identification of motor have been studying systematically for a long time. But, systematical study on harmonic parameters analysis for efficient motor drive system are very poor. The goal of this paper is to propose analyzing method of harmonic parameters for motor drive system with various experimental graphic screens and numerical results and to develope harmonic parameters analyzer. A developed analyzer is made up 586-PC and DSP (digital signal processor) board, motor drive system, power and harmonic parameters analyzing software for windows. Harmonic parameters are analyzed using correlation signal processing techniques based on the correlation between voltage and current waveforms. Analysis results are visualized by 3-D current coordinates, and it is compared and evaluated with conventional time/frequency domain. To verify the validity of the proposed system, 1/4HP capacitor run type single phase induction motor and thyristor speed controller is used for analyzing. Harmonic parameters of motor drive system is analyzed and verified, with varying fire angle of thyristor speed controller, and the proposed approach is to confirm validity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.390-395
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• 2000

The ultrasonic motor have recently begun to be used for certain unique practical utilizations in the fields of industrial medical consumer and automotive applications. Ultrasonic motor stimulated to ultrasonic oscillations by piezoelectrics to drive a rotor via friction contact. The metal and ceramic composite component was used as the stator element to generate ultrasonic vibrations. The ultrasonic motor used here was the windmill type ultrasonic motor operated by single-phase AC source. The windmill type ultrasonic motors has only three components; a stator element of two windmill shape slotted metal endcaps a rotor and a bearing. In this paper a prototype motor with 11.35 mm diameter was fabricated then relationship between the pressing force applied to a rotor and the rotation characteristic of windmill type ultrasonic motor are investigated when stator’s slots was changed from 4, 6, 8 and thickness changed from 0.15, 0.20 mm, respectively. Optimum pressing force applied to a rotor in the six stators was 1.2 mN.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.615-619
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• 1992

This paper describes the specifications of proto type linear pulse motor (LPM), the systems of driver and measurement. Also the following characteristics of this LPM is experiments -. Static thrust characteristics -. Dynamic thrust characteristics -. Normal force (attraction force ) -. Acceleration & deceleration characteristics etc. This LPM is Hybrid(HB), Transverse field machine(TFM) type single-sided flat type, 2-phase, 8-pole

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.522-525
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• 1999

This paper describes a simple but effective method for energy saving of ac motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, in voltage control with triac. In this paper, authors present the experimental results of the SPIM under controlling of current of main and auxiliary winding by using a one chip microcontroller. Experiments are focused on a capacitor stating single phase induction motor the optimal energy saving are proved by the proposed method.

• 전기의세계
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• v.17 no.1
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• pp.21-31
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• 1968

The variation of the voltage has been known to be harmful in the sound operation of motors. It also results in the variation in slip. If the voltage and slip are known, every characteristics of motors can be determined. This paper, therefore, analyzed numerically the characteristics of motors by the formula expressed in the function of both slip and voltage, and then satisfactorily compared with the experimental values. A new per-unit method derived in this paper is shown to be easier and simpler than the conventnional one in determining the relative running characteristics. It has also suggested the minimum allowable voltage when voltage below the rated value was applied to the motor. It is expected to apply to the determination of the characteristics under the voltage variation.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.343-350
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• 2016

Generally, the average phase current is sampled at the midpoint of a PWM signal for the vector control of an AC motor. The three-phase current can also be reconstructed from a DC-link shunt resistor by sampling the shunt voltage during the active vectors of the SVPWM. However, the reconstructed current is different from the average current because of the deviation of the sampling point from the midpoint of the PWM signal. This paper proposes an algorithm to estimate the average current from the reconstructed current in a single-shunt inverter. The proposed method is derived from the phase current slopes based on switching states and corresponding switching time. In addition, the proposed method is generalized for all the six sectors of the space vector hexagon. The validity of the proposed algorithm is verified with simulations and experiments.