• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.232-232
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• 2000

switched reluctance motors and drives are increasingly used in industrial applications due to their robust mechanical structure, low inertia and reduction in the rotor losses. As the motor speed increase turn on angle must be advanced to build up phase current. When C-dump converter is applied to switched reluctance motor, the capacitance of dump C has to have proper value. In this paper advance angle for a switched reluctance motor and capacitance of dump C are investigated. Then proper advance angle and the capacitance of dump-C are propose for the industrial low voltage SR motor.

• 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.

• 전기의세계
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• v.19 no.3
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• pp.10-17
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• 1970

The main focus of this paper is the analysis on the controlling characteristics of self-excited D.C. motor driven by thyristor chopper. The controlling characteristics of short shunt compound motor driven by poly phase multiple thyristor chopper is better than that of driven by single phase thyristor chopper. And we got the following conclusions. A. Motor current capacity could be increased by the multiplicity n increase. B. Speed-torque characteristics is linear and adquate for constant Horsepower motor. C. Maximum current Riple ratio is proportional to almost inverse m$^{2}$. Also here shows the stable conditions and semiconducterlize datas for controlling the self-excited D.C. motor driven by thyristor chopper.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.55-57
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• 2002

In industry, A pallet truck is drived mainly by d.c motor, because it use to battery for input power. However, d.c motor has a brush, this is the disadvantage of the d.c motor for a pallet truck. Though a brushless d.c motor has a permanent magnet, it is for low torque. Switched reluctance motors(SRM) have the advantage a high torque/weight ratio, as the large reluctance torque is made by salient poles of both start and rotor, and a high reliability, this paper design the shape of the switched reluctance motor that will replace a d.c motor for A pallet truck. First of all, designed parameter of SRM, outer diameter, diameter of rotor and stock length, from the outputr equation considering electric loading and magnetic loading. Next, design diameter of stator and rotor, depth of slot pole width, air gap as inner size of motor. The design of SRM certify the torque, the efficiency and the output power by a simulation.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.24-26
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• 1995

The Development of A.C. Induction Motor for Railway Rolling Stock. The traction motor is designed as 4-pole induction motor with self ventilation. The winding insulation is throughout of materials of class C. The rotor is designed as a squrrel rotor with copper bar and casting. The rotor speed is detected by means of a pulse generator. The newer tection motor have no casting(frame). Punched-in holes make up the air duct and transfer the heat losses in complete. Maximim motor rpm is higher due to rotor construction. New is the entry of water-cooled traction motors in urban, However the water cooling design in - unfortunately - not applicable in traction motor.

• 전기의세계
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• v.17 no.4
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• pp.7-12
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• 1968

In recent years the development of the SCR has made possible the control of the power system. It is one example that the speed control of the induction motor can be done by changing the frequency with the S.C.R. This paper is devoted primarily to a study of the running characteristics of the single phase induction motor through the experimental and theoretical methods when the speed of the motor is controlled by varying the conduction period in current with S.C.R. under the constant frequency. We conclude from the experiments that the adjustment of the phase angle in current is equivalent to the change of the supply voltage to the motor. Therefore, the speed control of the motor such as a fan duty motor is possibly by this methods.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.502-508
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• 2022

Objective: Contralateral seventh cervical nerve transfer (contralateral C7 transfer) is a newly attempted method to restore upper extremity motor function in the patients with spastic arm paralysis. The aim of this study was to investigate the effects of contralateral C7 transfer on upper extremity motor function in the patients with spastic hemiplegia after stroke. Design: A retrospective cohort study. Methods: Thirty-four patients with spastic hemiplegia after stroke was investigated. All patients registered between January 2020 and February 2021. The subjects were assessed on upper extremity motor function, cognition, and spasticity before and after contralateral C7 transfer. The upper extremity motor function was measured using the Fugl-Meyer upper extremity scale and box & block test. The cognition and spasticity were assessed by Korean version mini mental state examination (K-MMSE) and modified Ashworth scale from baseline to 8 weeks after the surgery. Results: The Fugl-Meyer upper extremity scale and modified Ashworth scale were significantly improved after contralateral C7 transfer (p<0.05). However, box & block test and K-MMSE were no significant changes after the surgery (p>0.05). Conclusions: This study suggested that the contralateral C7 transfer was a feasible and practical approach to improve upper extremity motor function in the patients with spastic hemiplegia after stroke, but further study is required to identify the long-term effects after the contralateral C7 transfer.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.257-262
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• 2001

In this paper, a linear ultrasonic motor using piezoelectric ceramics was fabricated, and its operation characteristics were investigated. A linear ultrasonic motor using L$_1$-B$_4$model was composed of a stator and a rotor, and a stator was composed of piezoelectric ceramics and a elastic body. When applied frequency and voltage were 58.4kHz and 56V respectively, the feeding speed of the motor was 19.8 cm/s. A linear ultrasonic motor could be moved in left and right directions by the phase difference. Feeding speed and feeding force of a linear ultrasonic motor could be controlled by applied voltage. A linear ultrasonic motor had a droping torque-speed characteristic. The maximum efficiency of linear ultrasonic motor was 2.14%. Therefore, this linear ultrasonic motor can be expected to be used for a card-forwarding device, such as a card reader device and so on.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.11
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• pp.1423-1428
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• 2013

In this study, a heat dissipation measurement system is developed to analyze a 1.2-kW BLDC motor. It is important to check the temperature of the motor because an increase in temperature causes problems in the motor insulations, which in turn influences the motor life. A generator for a vehicle is installed to set up a load. We changed the load from 165 to 495 W. While the rpm varies from 2000 to 4000 under various load conditions, the changes in temperature were measured for the operating period by using a thermocouple. The results of experiments conducted under natural convection conditions suggest that the temperature was not stationary with the rpm, load, and coil of the motor and it kept increasing over $120^{\circ}C$. However, under forced convection conditions, the temperature stationarily reached $84^{\circ}C$ after 4000 s. The difference between the maximum and the minimum temperatures was $10-26^{\circ}C$ with an increase in the rpm and load. The orders of high temperature were as follows: motor coil (Ch#1), side of motor surface (Ch#5), inside of motor cap (Ch#2), upper side of motor surface (Ch#4), and inner wall of the motor (Ch#3).

• Korean Journal of Clinical Laboratory Science
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• v.48 no.1
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• pp.41-48
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• 2016

Motor evoked potential of spinal surgery is known to cause damage due to the movement path of the continuous scan operation and surgery can be performed with minimized disability after surgery. However, if it is not at all formed at the wave motion evoked potential can occur during surgery and, in some cases the size of the waveform to be measured is very small and intermittent. In this case, the surgery cannot provide information about whether there is neurological damage. Increased intensity of the wave-induced motion of the dislocation does not occur if it appears in a very small amplitude stimulus, but changing the inspection area that electrical stimulation of the waveform changes could not be found. However, stimulation of a wide area in the cerebral cortex was found to occur with a waveform in the patients who underwent examination. Through this study, we propose a useful motor evoked potential test. From November to December 2015 three spine surgery patients visited Samsung Medical Center as neurosurgery patients with omission discomfort, gait disturbance, and no symptom of strength before surgery. In spine surgery patients with motor grade weakness, when motor evoked potential waveform has not been measured, in examination of the site of electrical stimulation of the cerebral cortex from entering the C3+C5/C4+C6 or C3+C1/C4+C2 if by the activity of more motor neuron unit, it was found that the waveform is better formed.