• Journal of Advanced Marine Engineering and Technology
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• v.27 no.6
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• pp.776-782
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• 2003

This paper describes a newly developed double squirrel cage induction motor in which the rotor is located outside the stator. The outside rotor type brushless dc motor has been used for VTR's head drum and PC's cooling fan, but this kind of induction motor has not been developed yet. The parameters of outside rotor type induction motor were measured from the locked rotor test and no load test. It is possible to determine the parameters which are presented in the steady-state equivalent-circuit of the outside rotor type induction motor. Load test of induction motor was carried out using a dynamometer. For the characteristics of torque, efficiency, power factor and output. the developed double squirrel cage induction motor is compared with the ordinary induction motor It is believed that the results of this paper can be used for the development of the outside rotor type induction motor.

• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.44-48
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• 2000

The high temperature superconducting bulk can be used as the rotor of an ac motor. This paper presents the fabrication and test results of a ac motor with HTS bulk rotor. The rotor of a conventional squirrel cage induction motor was replaced with cylinder type YBCO bulk. Height and outer diameter of the HTS bulk was 15mm and 46mm, respectively. Eddy current brake using aluminium disk was used to measure the torque of the HTS motor. No load test, locked rotor test and load test were performed to examine the characteristics of the HTS motor. Test results show the motor can rotate at synchronous speed without any special starting circuit. Maximum output power of the constructed HTS motor was 408W.

• Korean Journal of Child Studies
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• v.33 no.6
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• pp.21-34
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• 2012

This study examined the effects of physical activities using Korean dance upon the motor abilities of young children. The subjects of this study were divided into 2 groups. The first group was an experimental group (boy=12, girl=13) who participated in the Korean dance class and the other group was a comparative group (boy=11, girl=14). Experiments were performed during 18 sessions for 9 weeks. The study findings are as follows. First, physical activities using Korean dance had positive effects upon the development of basic motor abilities in young children. In terms of these basic motor abilities, movement motor ability and whole muscle operation motor ability showed significant differences between the pre-test and post-test stage in the experiment group and between the experimental and comparative groups in the post-test stage. On the other hand, in terms of non-movement motor abilities, there was a significant difference between the pre- and post-test stages for the experimental group, but no significant difference in the post-test stage for the experimental or comparative groups. Second, physical activities using Korean dance had positive effects upon the development of perceptive motor abilities in young children. In other words, in the sub-variables of perceptive motor abilities, there were significant differences between the pre- and post-test stages of the experimental group which experienced physical activities using Korean dance. In conclusion, the study findings showed that physical activities using Korean dance had positive effects upon the increase of both basic motor abilities and perceptive motor abilities in young children. Additionally, the experimental group exhibited more positive effects in the various areas of motor abilities than the comparative group.

• Journal of Applied Reliability
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• v.18 no.3
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• pp.193-200
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• 2018

Purpose: In this study, the life of the motor is investigated by performing the accelerated life test with the brush wear of the industrial cleaner motor as the main failure mode. Methods: The accelerating stress factor of the accelerated life test is a voltage, which can increase the number of revolutions of the motor to accelerate the brush wear due to the friction between the brush and the commutator. Also, the accelerating stress level was determined after determining the maximum allowable level of the voltage through the preliminary test. Results: The motor failure time at each accelerating stress level was predicted by regression analysis with brush wear length as performance degradation data. The main failure mode, which is brush wear, of the motor was reproduced by this test. The shape parameter of the Weibull distribution was confirmed to be the same statistically at all accelerating stress levels by the likelihood ratio test. Conclusion: The life of the motor was investigated by performing the accelerated life test with the brush wear of the industrial cleaner motor as the main failure mode. Through the accelerating test method of the cleaner motor, various life expectancy and life expectancy of the acceleration factor are predicted.

• 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.

• Journal of Applied Reliability
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• v.15 no.4
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• pp.241-247
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• 2015

Purpose : The demand for higher fuel economy vehicles has helped develop fuel-efficient vehicles such as a CVVL called continuous variable valve lift. Existing CVVL has been applying DC type motor to control intake valve, but recently some car parts manufacturers have been developing a BLDC type CVVL motor for improvements of endurance performance. The purpose of this study is to find the potential failure mechanism of the CVVL BLDC moto in early stage of development based on the design properties and design the accelerated life test model. Methods : CVVL BLDC is consist of brushs, coil, magnetic, PCB, bearing and so on. Each component has a latent failure mechanism caused by temperature, humidity, vibration. By analysis result of the failure mechanism, thermal fatigue is the most important factor of a durability of CVVL BLDC motor. So, we designed a new accelerated life test model for guarantee of the CVVL BLDC motor. Results : A crack occurred on via hole in test using the conditions we designed, so we did change the design to avoid this failure. The via hole dimension is changed a little larger, as a result we achieve improvements in reliability of the CVVL BLDC motor. By applying various kinds and extreme level of stresses, we can find the operating limits of products. Conclusion : In thesis, We analyzed the failure mechanism of CVVL BLDC and designed an accelerated life test method to give a guarantee for reliability. Based on the test results, we could improve the reliability of developments by change of design.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.4
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• pp.328-335
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• 2003

Test procedure for Electric Vehicle(EV) motor/controller has been developed. Most of existing standards mainly focus on minimum requirements for safe operation. However, detailed test procedures are not covered in the standard. In order to develop test items, methods and procedures which should be strictly applied to EV motor and controller, existing standards have been reviewed by the expert group in Korea. Based on their feedback, standard test procedure was proposed. Test procedure especially for combined motor and controller has been proposed. As a load lot the tested motor, M-G set, eddy current type engine dynamo and AC dynamo were used. Test procedures for the driving cycle test and regeneration test were proposed.

• The Journal of Korean Academy of Sensory Integration
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• v.11 no.2
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• pp.41-56
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• 2013

Objective : The purpose of this study tried to present the performed average and range through systematic review about assessment tools that measures the praxis ability of sensory integrative function for foreign and domestic normal children. Methods: With making use of Medline, PubMed, Ovid, Eric, the Library of Congress, National Science and Technology Information Center, Kiss, RISS, and the Google search engine, we searched the name of assessment tool on the basis of the framework of the theory of sensory integration. Target paper was thesis and Journal published from January 2000 to April 2011. Results: Total of 24 papers were retrieved, used assessment tools were Bruininks-Oseretsky Test of Motor Proficiency (BOTMP), Bruininks-Oseretsky Test of Motor Proficiency, Short Form (BOTMP-SF), Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2), Bruininks-Oseretsky Test of Motor Proficiency, Second Edition, Short Form (BOT-2-SF), Clinical Observations of Motor and Postural Skills (COMPS), Motor Assessment Battery for Children (MABC), Clinical Test of Sensory Interaction with Balance (CTSIB), and subtest of Sensory Integration and Praxis Test (SIPT). We presented the average and range of assessment tools applied to normal children in each country. Conclusion: A performed result in other cultural and domestic normal children which this study presented will provide a standard in comparison with performance of children with disabilities who are the actual clinical evaluation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.6
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• pp.286-290
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• 2003

The high temperature superconducting bulk can be used as the bearing of induction motors. This paper presents the fabrication and test results of an induction motor with superconducting bearings using HTS bulks. The bearing had eight hexahedron type YBCO bulks. Height, width and thickness of the HTS bulk were 30mm, 30mm and 10mm, respectively. Single phase induction motor was used to drive the shaft made of aluminum and the rotor of a conventional induction motor. To estimate the performance of the HTS bulk magnetic bearing, no load test, load test and Impact test were carried out. Load tests were performed by using air resistance caused by the shaft-mounted thin cylinder with buckets. Impact tests by axial direction and vertical direction impact showed that the vibration of the shaft gradually decayed. The induction motor with HTS bulk magnetic bearing rotated silently and smoothly throughout the tests. According to the test results, conventional bearings can be replaced with superconducting magnetic bearings made of HTS bulks.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.34-42
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• 2000

In this paper conventional technique will be described, which can be used for the measuring various parameters of induction motor. This is followed by presenting some other, alternative, techniques. The two tests are described which are suitable to obtain the electrical parameters of symmetrical 1hp three-phase squirrel-cage induction motor. These are the blocked rotor test and no load test. By the application of these, it is possible to determine the parameters which are presented in the steady-state equivalent-circuit of determining an induction motor. One conventional method of determining the inertia of an induction motors is obtained by performing retardation tests. The angular rotor speed of the motor is monitored, following its disconnection from the stator supply. Since the inertia torque J dw/dt contains the inertia coefficient J and the friction and windage torque Bw contains the coefficient B, then J and B can be determined by performing retardation tests.