• Title/Summary/Keyword: Measuring Principle

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Development of the Measuring System of the Rotational Accuracy of main Spindles (주축의 회전정도 측정시스템의 개발)

  • Sin, Yeong-Jae;Park, Jong-Gwon;Lee, Hu-Sang
    • 한국기계연구소 소보
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    • s.20
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    • pp.21-26
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    • 1990
  • In order to satisfy the industrial requirements to measure the rotational error motion of main spindles and to find out the source of the error motion, some measuring systems were made. Their measuring principle are based on the 3-point roundness measurement. In these measuring systems, the measurements are processed by digital calculation technique and the form error and the rotational error motion of main spindles are spearated. In the present paper, the principle of 3-point metnod is introduced and some application examples are shown.

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Surface measurement using Confocal principle (공초점 원리를 이용한 표면 현상 측정)

  • 송대호;유원제;강영준;김경석
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.51-54
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    • 2000
  • The traditional surface measuring method using confocal principle requires much time to measure an object surface since it is a scanning tool. In this paper, the upgraded confocal microscope is introduced. It is also a scanning tool but it requires 2D-scanning while the traditional one requires 3D-scanning. It means the time for measuring is considerably reduced. In addition, the measuring system is configured to increase the efficiency of beam. He-Ne laser whose frequency is 632.8nm is used for the laser source. An example of measuring result through the upgraded confocal microscope is showed.

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Teachers' & Students' Concepts of the Measurement of the Size of the Earth

  • Chae, Donghyun;Han, Jejun
    • Journal of The Korean Association For Science Education
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    • v.33 no.3
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    • pp.639-649
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    • 2013
  • The purpose of this study is to figure out how teachers conduct an experiment in measuring the size of the Earth and how students recognize it. For this study, an in-depth interview was conducted one week after the lesson on the experiment about measuring the size of the Earth. The participants were five secondary school teachers and five secondary school students. The in-depth interview was recorded and transcribed. The result of the interview was drawn through an inductive categorized analysis method. As a conclusion of this study, the teachers taught the students the lesson using alternate angles instead of using the altitude of the Sun. Their lessons were based on Eratosthene's story or some related illustrations suggested in the textbook and not based on an explanation of the principle. Also, students measured the Earth's size only by using alternate angles and didn't understand the meaning of the shadow in the experiment. The results of this study show that teachers need to reconstruct the textbook and understand the accurate experimental principle for the students to have a meaningful experience of the experiment on measuring the size of the Earth.

Two Plane Balancing Method based on the Equations of Motion of Rotor Dynamic System (회전체 동역학계의 운동방정식에 근거한 양면 밸런싱 기법)

  • Jeong, Dong-Hwa;Park, No-Gil
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.623-628
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    • 2000
  • Since the influence coefficients method in balancing of rotors is developed with the basement of not the principle of rotor system dynamics, but the linear relationshop of between the measuring quantities and the unbalance quantities, field engineers can apply the method without additional understanding on the rotor dynamics. But the influence coefficients method is not robust to the measurement error. This paper proposes a new method for the two plane balancing of rigid rotor, based on the principle of rotor dynamics. And the kit for experiment is made by ourselves, and in order to measure in the same condition with it, we do a experiment three times. And then with the Response of gap sensor, the SNR(Signal and Noise) is compared and analyzed about measuring error between the influence coefficient method, and the new method, and it is proved that the new method is less robust than the influence coefficient method.

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Characteristics for Ground Impedance of Counterpoise according to Position of Auxiliary Probe and Frequency (보조전극의 배치 및 주파수에 따른 매설지선의 접지임피던스 특성)

  • Gil, Hyoung-Jun;Kim, Dong-Woo
    • Journal of the Korean Society of Safety
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    • v.27 no.4
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    • pp.33-37
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    • 2012
  • This paper describes the characteristics for ground impedance of counterpoise according to position of auxiliary probe and frequency using the fall-of-potential method and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position of auxiliary probes. In order to analyze the effects of ground impedance due to the distance of the current probe and frequency, ground impedances were measured in case that the distance of current probe was located from 10[m] to 100[m] and the measuring frequency was ranged in 55 [Hz], 128[Hz], 342[Hz], and 513[Hz]. The results could be help to determine the position of auxiliary probe when the ground impedance was measured at grounding system.

The Development of Portable Body Fat Meter (휴대용 체지방계의 개발)

  • Park, Jong-Chan;Lim, Eung-Choon;Park, Su-Hong;Han, Un-Dong
    • Proceedings of the KIEE Conference
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    • 2003.07e
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    • pp.34-37
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    • 2003
  • The purpose of this paper is the development of portable body fat meter. Bioelectrical impedance method for measuring human body composition is based upon the principle that the electrical conductivity of the fat mass is far greater than that of the fat. Finally measurement of percent body fat was made possible using a developed impedance measuring device which measure impedance between the thumb and ring finger.

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Study on the Magnetic Field Measurement Using the Ultrasonic Transducer (초음파진동자를 이용한 자계측정방법 연구)

  • 손은영;류주현;윤광희;정영호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.350-355
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    • 1997
  • A new magnetic field measuring system with induced coil is reported. This system consists of air-cared coil that is forced by the ultrasonic transducer. Induction voltage of coil is proportional to the DC magnetic field and the driving frequency of ultrasonic transducer by the principle of Faraday's law. The experimental measuring system is setup, and the possibility of a new magnetic field sensors is confirmed.

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A study on the sensor for measuring the transient electric fields (시변성(時變性) 전계(電界) 측정용(測定用) 센서에 관한 연구)

  • Lee, Bok-Hee;Paek, Yong-Hyun
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.318-321
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    • 1991
  • For measuring the transient electromagnetic fields and related quantities created by disconnector operations in GIS, one needs the wide bandwidth sensors with simple transfer functions. This paper describes a new developed electric field sensor to measure the very fast transient electric fields and voltages, and the measuring principle, design and construction of planar electric field sensor are described. A calibration and/or correction technique of the sensor is investigated which enables an accurate determination of the sensor response to the time-changing electric fields. As a consequence, the low voltage calibrations certify that a rise time of 1.7 [ns] is achieved for the planar electric field sensor and a total bandwidth extending from several Hz to 200 MHz for the measuring system which presents the constant division ratio as a function of frequency.

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Development of a profile measuring system for conductor roll (전기도금 롤의 형상 측정시스템 개발)

  • Choi, Yong-Jun;Jun, Sung-Bai;Lee, Eung-Suk;Kim, Hyo-Sung;Jang, Ji-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.10
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    • pp.1730-1741
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    • 1997
  • In this paper, we developed a surface profile measuring system and a profile measuring software for EGL conductor roll. For the profilemeter, we designed a linear guided control system with Laser displacement sensors and developed a 3-dimensional software. Additionally, the AC motor and AC motor driver were used to control the precise position of linear guide system. The measuring principle of the Laser sensor is optical triangulation method. Also, two Laser sensors were used to remove the disturbance and vibration effects of the linear guide system.