• Journal of Korea Society of Industrial Information Systems
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• v.25 no.5
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• pp.49-57
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• 2020

Conventional electric motors are not suitable for aircraft because of their large size and weight. High-temperature superconducting (HTS) motors have high current density, high magnetic field density, and low loss, so they can significantly reduce the size and weight compared to general electric motors. This paper presents the conceptual design and analysis results of HTS motors for electric propulsion in future aircraft. A 2.5 MW HTS motor with a rotational speed of 7,200 RPM was designed and the specific power (kW/kg) was analyzed. The operating temperature of the field coil of the HTS motor is 20K in consideration of LH2 cooling. The stator winding were connected in a multi-phase configuration and Litz wires were used to minimize eddy current losses. As a result, it was confirmed that the specific power of the motor is about 18.67 kW/kg, which is much higher than that of the conventional electric motor.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.642-647
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• 2018

Gas compressors are mostly driven by motors. It is important to measure the power of motors to evaluate their power efficiency, because the mechanical loads of gas compressors are always varied. In order to measure the power given to the driving motors, the torque should be measured. Manufacturers of compressors usually use the torque data to calculate the compressors qualities such as power consumption, efficiencies and failures. In general, measurements for the shaft torque of the compressors have been based upon contact types, strain gauges. In the cases of larger compressors, the contact type of strain gauges have several disadvantages such as large size and high cost. In this study, a relatively inexpensive and simple torque sensing technique that is not restricted to shaft diameter is introduced using visualization technique. Particle image velocimetry (PIV) has been adopted to complete non-contact torques measurements for rotating motors. In order to compare the performance of the newly constructed torque measurement technique, torque measurement by a transducer based on MEMS technology has been performed simultaneously during experiments.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.648-651
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• 1996

Samsung Electronics has developed high performance velocity and position controller for induction motors, and succeeded in mass production for the first time in Korea. Dynamic performance and final control accuracy of the controller are equivalent to those of AC servo motor controller. At present, we adopted the controller as spindle motor drive for Samsung CNC systems, and expect its wide use in industry as general purpose velocity and position controller for induction motor.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.24-29
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• 1991

RCCL(Robot Control C Library) is general purpose robot control language. It is programmed with C language and composed of C library. So it is well portable and supports sensor integration control and high level force control algorithms. We implemented RCCL on PUMA. We developed servo controller of DDC(Direct Digital Control). We used intel 8097BH one chip micro controller as CPU. One digital servo board controls three motors. Host computer is IBM PC 386DX-33 with RCCL.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.11-14
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• 1996

Samsung Electronics has developed high performance velocity and position controller for induction motors and succeeded in mass production for first time in Lorea. Dynamic performance and final control accuracy of the controller are equivalent to those of AC servo motor controller. At present we adopted the controller as spindle motor drive for Samsung CNC systems and expect its wide use in industry as general purpose velocity and position controller for induction motor.

• International Journal of Quality Innovation
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• v.1 no.1
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• pp.24-31
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• 2000

QS-9000 was established by Chrysler, Ford, General Motors and some Truck Manufactures to solve problems of efforts to prepare original standards for each company. When we compare the requirements in QS-9000 with those in ISO 9000, we may observe that those of QS-9000 are more specific, since the user of the standard is limited to the automobile industry. In particular, the requirements on statistical techniques are described in more detail. In this paper, we present the requirements on statistical techniques in QS-9000. Specifically, we review the contents of QS-9000 and explore the philosophy and the minimum requirement on statistical techniques behind the description.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.427-435
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• 2006

We study on the consistency of AHP. It is research that extend of SAW methods by [1]. For tools that measure judgment of inconsistency eigenvector methods, we research consistency that introduced consistency ratio by Saaty. in general, the higher consistence of compare matrix the bigger error within matrix. In this paper, we use the AHP for the optimal decision making. By this method, we have optimal decision making numenical example which three models of any domestic motors companies.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.349-350
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• 2007

In general, PID controller is widely used for speed control of motor. PID control method is easy and simple to set the control gains without model parameters. However, the precise and robust control of the motors needs complex and difficult control method. In this paper, we present a simple and robust speed controller for disturbances of a motor. The numerical simulation shows that the proposed control considering disturbances can improve the speed tracking performance more than PI control.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.201-209
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• 1999

This paper presents a general analytical method for analyzing mechanical unbalance response of unbalanced electromagnetic forces produced in induction motors with an eccentric rotor and a phase unbalance. The equations to be solved are a set of second order differential equations which give matrices with periodic coefficients that are a function of time due to the unbalanced electro-magnetic force. Unbalance response is processed by Newmark $\beta$ method. Two examples are given including an industrial application. The results show that the method proposed is satisfactory.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.9
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• pp.427-433
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• 2001

A linear ultrasonic motor was designed by a combination of the first longitudinal and fourth bending mode, and the motor consisted of a straight aluminum alloys bar bonded with a piezoelectric ceramic element as a driving element. That is,$L_1-B_4$ linear ultrasonic motor can be constructed by a multi-mode vibrator of longitudinal and bending modes. Linear ultrasonic motors are based on an elliptical motion on the surface elastic body, such as bar or plates. In general, the natural resonance frequency of the stator is used as a driving frequency of the motor which provides a large elliptical motion. The corresponding eigenmode of one resonance frequency can be excited twice at the same time with a Phase shift of 90 degrees in space and time. And the rotation can be reversed by changing the phase between the two signals from sin$\omega$t to cos$\omega$t. Moreover, the tangential force pushes the slider(rotor) and, therefore, determines the thrust and speed of the motor. The experimental results of fabrication motors, bimorph-tyPe motor showed more excellent than unimorph-type. The maximum speed of TBL-200, TBL-300, TBL-400, TBL -220, TBL-310 and TBL-420 motors were 0.12, 0.37, 0.39, 0.14, 0.55 and $0.60ms6{-1}$, respectively. And the efficiency were reported 1.15, 7.9, 6.6, 2.36, 10.1 and 16.5%, respectively. That time, output thrust of the motor was a strong(1~2N) and the weight of stator was a lightness(5~7g).