• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.33-37
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• 2004

This paper presents the construction and test results of an HTS induction motor. End rings and short bars were made of HTS tapes, To increase the efficiency and starting torque, HTS tapes can be used as the rotor bars. Because large current is induced in the rotor circuit, HTS tapes quench and high starting torque can be obtained. As the speed of rotor builds up. HTS tapes which are used as short bars become superconducting state again. After the HTS tapes recover from quench, resistance of the rotor circuit is nearly zero. In that case, power loss in rotor circuit is eliminated. Stator of the conventional induction motor was used as the stator of the HTS motor. Rated capacity of the conventional motor was 0.75 kW. Performances of the HTS induction motor were compared with those of the conventional motor with same volume and specification. Test result showed that the speeds of the HTS induction motor were the same with synchronous speed up to 2.6 Nm and 1.788 rpm at 9.7 Nm. It guarantees the high efficiency of the HTS motor. Starting torque of the HTS motor was more than twice of the conventional motor.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.739-740
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• 2006

According to the rapid growth of high speed and precise industry, the application of synchronous motor has been increased. In the application fields, the large synchronous motor is not a self-starting motor. The rotor is heavy and, from a dead stop, it is impossible to bring the rotor into magnetic lock with the rotating magnetic field for this reason, all synchronous motor have some kinds of starting device. A simple starter is another motor which brings the rotor up to approximately 96 percent of it synchronous speed. The starting motor is disconnected and the rotor locks in step with the rotating field. The more commony used starting method is to have the rotor to include a squirrel cage indution winding. This indution winding brings the rotor almost to synchronous speed as an induction motor. So, this paper describes excessive condition interpretation of a exciter circuit to prevent starting failure of large synchronous motor. the large synchronous motor needs safety of it in accordance with operating frequent start and stop. the operating Problem point of synchronous motor appears potential element damage of Exciter circuit because synchronous motor is caused synchronous separation. hence we eliminate it and improve starting toque.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.178-184
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• 2016

The motor power of the industry to use the electric energy is gradually increased. The electric motor generates a voltage drop in the starting current during startup. The starting current is started it is difficult to have an adverse effect on neighboring power systems with large motor starting when the voltage drop across the power grid. In addition to that the motor torque according to the load depending on the size of the rotation speed is changed to a motor start-up speed is important. However, the distance to the emergency generator transformers or motors from the motor capacity is smaller but short and difficult to maneuver the theory and practice of the operating characteristics of the starting characteristics of the motor used a lot of large industrial plants were measured and analyzed. Therefore, this study investigated the motor starting Analysis and interpretation for the relationship with the large motor starting torque and speed during motor starting.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.1
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• pp.24-30
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• 1996

BLDC motor is widely used as a servo motor, because it has high efficiency, high power ratio, low inertia, and easy maintenance. However, position and speed sensors generally attached in BLDC motor increase motor cost, and limit environments of application. This study describes a sensorless speed control of sinusoidal BLDC motor using the d-q transformed instantaneous voltage equation, and presents the result of computer simulation. The sensorless algorithm is applied to the casse of a voltage controlled PWM inverter. The result indicates good dynamics and a robust control in cases of a load change and a system parameter variation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.641-645
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• 2008

In this paper, vibration sources of the BLOC motor are identified and the motor vibrations are reduced by structural modification. For vibration characteristic identification, vibration signals measured by an accelerometer when the BLOC motor is moving. These signals are presented in a waterfall plot in order to find the dependency of frequency components on the motor speed. It is found that main vibration source is BLOC motor test rig. From finite element analyses and some experiments, it is also found that resonances occur because the natural frequencies of the test rig exist in usual driving speed rang. To shift the natural frequencies outside the driving rang, the test rig is modified increase stiffness. It is verified that considerable amount of vibration are reduced by the structural modification.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.3
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• pp.123-127
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• 2004

Mode conversion type ultrasonic rotary motor using bolt tightened Langevin type vibrator was studied. Driving frequency of the motor, displacements and elliptical trajectories at tip of the coupler were simulated by finite element analysis program (ANSYS). Speed and torque of the fabricated motor were measured as functions of input voltage and load. As results, from FEA the driving frequency of 40.8[kHz] and useful elliptical trajectories were found. Fabricated motor rotated clockwise at frequency of 38.2[kHz]. Speed and torque of the motor were increased when the input voltage was increased. Maximum speed, torque and efficiency were 75[rpm], 0.14[Nm] and 6.28[％], respectively.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.207-213
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• 2000

This paper introduces a high-performance speed control system based on artificial neural networks(ANN) to estimate unknown parameters of a DC servo motor. The goal of this research is to keep the rotor speed of the DC servo motor to follow an arbitrary selected trajectory. In detail, the aim is to obtain accurate trajectory control of the speed, specially when the motor and load parameters are unknown. By using an artificial neural network, we can acquire unknown nonlinear dynamics of the motor and the load. A trained neural network identifier combined with a reference model can be used to achieve the trajectory control. The performance of the identification and the control algorithm are evaluated through the simulation and experiment of nonlinear dynamics of the motor and the load using a typical DC servo motor model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.165-170
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• 2015

In this paper, The strength and driving characteristics of it were investigated according to developing the traction motor for 8200 electric locomotive series. For this purpose, Flux density strength was analyzed and then structural strength was investigated such as a stator frame, design of the rotor shaft bearing according to the design process. In addition, the traction motor operating point was analyzed according to slip frequency variation at a power source frequency. As the results of analysis on torque-speed characteristic curve, we was confirmed that traction motor was controlled as torque control prior to motor speed 1610[rpm], power control between 1610[rpm] and 2500[rpm] and breakdown torque control more than motor speed 2500[rpm].

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.3
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• pp.56-63
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• 1989

In recent years, a.c servo motors have been gradually replacing d.c sevo motors in various high-performance demanded aplications such as machine tools and industrial robots. In particular, the high-performance slip-frequency control of an induction motor, which is often called the vector control, is considered one of the best a.c drive. In this paper, the transient state equation and vector control algrithms of an induction motor are described mathematically by using the two-axis theory(d-q coordinates). According to the result of these algorithms, we scheme the speed control system for an induction type ac servo motor in which vector control is adopted to give tha a.c motor high performance. Motor drive is a PWM inverter using power MOS-FET, and is controlled in order to let the actual input current of the motor track the current reference obtained from a microcomputer(8086 cpu). Driving experiments are performed in the range of 0 to 3000 rpm, and it is verified that high speed response is possible.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.70-76
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• 2007

The purpose of this study is to analyze the characteristics of a domestic developed hydraulic axial piston motor. An experimental apparatus was constructed and the output torque, the input oil pressure, the input flow rate, the speed of motor and oil temperature were measured. They were measured under both no load and load conditions. The results are as follows; 1. Motion of motor became steady state conditions after 5 seconds. 2. Output torque of motor was proportional to input oil pressure under both load and unload. 3. Speed of motor decreased with increasing load. 4. Oil temperature was almost constant. The results of this study will offer the basic data in designing and operating hydraulic axial piston motors.