• 전기학회논문지
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• 제57권9호
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• pp.1589-1593
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• 2008

The condition of a high voltage motor was monitored with the motor performance monitor (MPM) at the motor control center. The MPM detected defects in the rotor bar and end ring and input power according to motor and load conditions. The assessment of the condition of a coal pulverizer motor indicated it was clearly in good condition in terms of the rotor bars, over voltage, and motor performance. However, the side bands at frequency, 56.48 Hz indicated existence of rotor end-ring fault. The large torque ripple indicated abnormal operating conditions. After visual inspection, it has been observed that an impeller blade of the circulating water pump was broken off causing the irregular torque pattern.

• 전기학회논문지
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• 제60권4호
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• pp.771-775
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• 2011

This paper presents design process of linear induction motor in dynamic tester for catenary-current collection. To minimize length of rail for dynamic tester for catenary-current collection, accelerating performance of the linear induction motor is very important. So the design process of linear induction motor considered in this paper is different with general design process of linear induction motor, because dynamic tester has three type driving region, as accelerating region, constant speed region, and braking region. Considering accelerating performance of motor, distance and time from starting point to constant speed region were concerned for load condition of motor. Designed linear induction motor was analyzed by 2-dimensional finite element method. Using mechanical dynamics simulation with analysis result of 2-dimensional finite element method and accelerating performance of designed motor was proved.

• 대한물리치료과학회지
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• 제7권1호
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• pp.333-352
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• 2000

The objective of this study was to identify the effects of the cognitive performance of stroke patients on their motor function recovery after comprehensive rehabilitation management. The subjects of this study were 41 stroke in-patients of the Rehabilitation Hospital, College of Medicine, Yonsei University, hospitalized during the period from September 1, 1997 to May 5, 1998. The cognitive performance was measured using a Mini-Mental State Examination(MMSE) and the motor function recovery using Motor Assessment Scale(MAS). The data were analyzed by the paired t-test, independent t-test, a one way ANOVA, and Pearson's correlation coefficiency. The findings were as follows: 1. There was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 2. There was no significant difference found in relation to sex, age, cause of stroke, laterality of paralysis and the level of spasticity. However, there was a big difference between pre- and post-treatment regarding the treatment period. 3. In line with the cognitive performance level, there was a significant difference found in the motor function recovery level after the comprehensive rehabilitation management. 4. The correlation between the elements of the cognitive performance and the motor recovery was found to be high in orientation, attention, calculation, and language. Those elements were expected to give larger effects on motor recovery after the comprehensive rehabilitation management. Based on this study, the cognitive performance level was found to play an important role in bringing effects on motor recovery after the comprehensive rehabilitation management of stroke patients. And the evaluation on the motor recovery based on quality would be also expected to be examined, as well as the cognitive performance level test accompanied by Intelligence Quality(IQ) test.

• 전자공학회논문지
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• 제52권8호
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• pp.126-131
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• 2015

유도전동기의 고성능 속도 제어를 위해서는 전동기 정수의 정확한 측정이 필요하다. 특히 전동기의 토크 제어를 위해 사용되는 벡터 제어의 경우 회전자 저항과 인덕턴스의 항으로 주어지는 시정수는 제어기의 성능에 큰 영향을 준다. 또한 고정자 저항과 누설 인덕턴스는 전류제어기와 속도 제어기의 이득을 구하고 설계하는 중요한 변수가 된다. 본 논문에서는 기존의 정수 측정 방법을 수정 보완한 새로운 유도 전동기 정수 측정방법을 제시한다.

• 동력기계공학회지
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• 제10권4호
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• pp.11-16
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• 2006

This research is to verify the cooling effect of the acting surface on the rotary motor using heat pipe and conventional cooling fan. In order to show the cooling performance of the rotary motor and heat pipe with the fin-typed heat sink, the surface temperature of the motor and condenser was measured in real time. The experiments were also conducted as for not only cooling device installed with heat pipe only, but with heat pipe and conventional cooling fan simultaneously. The present experiment reveals that the cooling combination of the heat pipe and cooling fan is far superior to the conventional cooling device for the driving motor such as the fin-typed heat sink. When the driving voltage of 20V and 14V were supplied to the driving motor, the cooling performance of the rotary motor with heat pipe was 170% and 500%, respectively better than that without heat pipe on steady state condition.

• 조명전기설비학회논문지
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• 제27권12호
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• pp.125-132
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• 2013

This paper has done a three-dimensional FEM analysis of the PM claw pole stepping motor. As magnetization happens in the z-axis, which does not have a constant value, three-dimensional FEM analysis is necessary for characteristic analysis of PM claw pole stepping motors. Because it is a type of permanent magnet motor, the PM claw pole stepping motor naturally has a detent torque. This torque is known to show negative effects on motor performance. To improve motor performance, reducing the detent torque is very important during the motor design. This paper applied DOE for optimization of stator pole design of the motor. Also, we compared motor performance by applying a different type of rotor shape, dividing the permanent magnet. To verify the simulation results, an experiment was done.

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.77-82
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• 2009

In robot operation, a motor with multi-degree of freedom motion control and an encoder for motor control are needed. To perform precise motion, location, and velocity control, the operation of motor and encoder with superior performance is important. In this paper, we studied performance evaluation system that can evaluate the performance of motor and encoder. The performance of motor and encoder can be evaluated in terms of disconnection check, signal variation count, and U, V, W signal check. Disconnection check verifies signal connection between a motor and an encoder, signal variation check verifies A, B signal by counting the number of signal A, B when a motor revolves, and U, V, W signal check verifies operating direction of a motor. The result is shown at graphic LCD integrated in system, and can be checked in PC with PC communication.

• 산업기술연구
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• 제17권
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• pp.79-85
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• 1997

This paper describes a control for the high performance induction motor drive system with a wide speed operating range and proposes a robust control method independent of motor parameter variation. For the operation below the rated speed, the high performance control is achieved by using the indirect field-oriented control with a speed sensor. In the high speed regain, the field weakening region with a large variation in motor parameters, the motor drive system can obtain the robustness to motor parameter variation by switchover to the direct field-oriented control. Also, the sensorless speed control using estimated speed is achieved in very high speed region that the utilization of speed sensor pulses is limited. And from experiments using high performance 32bit DSP for 2.2[kW] and 22[kW] laboratory induction motor drive systems, it is verified that the proposed opration algorithm provided a good performance.

• 대한기계학회논문집A
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• 제30권5호
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• pp.609-614
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• 2006

Recently linear motor has been used mainly for high speed feeding performance of machine tools. The advantages of linear motor are not only high speed but high accuracy, because it is not required the coupling and ballscrew for converting rotary to liner motion. Before applying in different moving system, the dynamometer is necessary to test the performance. In Korea, the linear motor is producing in a couple of company However, the liner motor dynamometer is not commercialized yet, like as rotary motor dynamometer. In this paper, a linear motor dynamometer is designed and manufactured using a MR damper. The dynamometer system developed in this study could be used for testing the positioning accuracy fur different loading conditions, traction forces, dynamic performance and so on.

• 한국공작기계학회논문집
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• 제16권1호
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• pp.19-25
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• 2007

Items and methods of synchronous type AC servo motor's performance evaluation were researched. Through the research, nine items of performance evaluations were selected from study of IEC standards and domestic technical reports. Using the proposed evaluation items and methods, performance evaluations were carried out into two domestic products and one foreign product for analysis of what results means. The results show that the proposed items of performance evaluations are reasonable and proper for performance evaluations of AC servo motors.