• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.3
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• pp.53-60
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• 2003

A test stand was developed to measure static performance of a reciprocating engine on the ground, related to the small aircraft being developed by KARI. The test stand consists of an apparatus to install and operate a pusher-type propulsion system and a data acquisition system to process many performance parameters including engine torque and propeller thrust as well as monitoring of the engine operations. First, the performance data from the basic operation tests were compared with the original engine data so the capacity of the test stand was verified. Engine performance tests were carried out with various test conditions through three stages, and it was measured and analyzed that the manifold pressure, the torque, and the back pressure of the engine, and the static thrust of the propeller.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.10
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• pp.107-113
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• 2002

To monitor the torque of an induction motor using current, rotating speed has been measured and used to calculate the slip angular velocity. Additional sensor, however, can cause extra expense and trouble. In this paper, a new algorithm is proposed to monitor the torque of vector controlled induction motor without any speed measuring sensor. Only stator current is measured to estimate the magnetizing current which is used to calculate flux linkage, rotor velocity and motor torque. Graphical programming is used to implement the suggested algorithm and to monitor the torque of an induction motor in real time. To solve the fluctuation problem of estimated torque caused from instantly varying rotating speed of an induction motor, the rotating speed is reconstructed based on the measured current signals. From several experiments, the proposed method shows a good estimation of the motor torque under the normal rotational speed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.1-7
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• 2016

The cutting processes used for monitoring engineering includes analysis and feedback about strange conditions, tools collision and tools wear in real time, for improving the working ratio of equipment and productivity. In this study, we proposed monitoring using profibus to increase the reliability as the most important factor for cutting monitoring. The profibus can increase the reliability of cutting monitoring for cutting torque of a main spindle motor and a feed motors through PLC-based interface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.564-567
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• 2005

For the application of monitoring system of the machine tool to industry, the requirements such as high reliability and low cost need to be satisfied. In this study, a reliable but inexpensive monitoring method for machine tool is introduced. To improve the monitoring reliability, several kinds of information related to machining and operation are selected; real-time video clip from USB camera, operation data and signal from CNC and feed motor torque. Especially, to improve the quality of real-time video clip, a camera housing is developed, it can significantly reduce the vibration effect and prevent from coolant and chip. The collected information are transferred to the monitoring terminals in remote sites using OPC and TCP/IP protocol over Ethernet, which give us convenience of development and interoperability.

• JOURNAL OF ELECTRICAL WORLD
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• s.299
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• pp.70-75
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• 2001

최근 몇 년 사이 설비투자가 억제되어 고경년(高經年)변압기나 과부하로 운전조건이 어려워진 변압기가 증가하고 있으며, 이에 따라 기기의 운전신뢰성 유지와 정비$\cdot$보수를 위한 토털코스트의 삭감 요구가 제기되고 있다. 변압기의 운전신뢰성을 유지하기 위한 센서 및 장치는 점검$\cdot$순시의 지원, 이상징후의 검출은 물론 기기의 상태를 정확하게 파악함으로써 적절한 유지보수의 지원을 목적으로 하는 것이 제품화되어 있다. 이와 같은 변압기의 감시$\cdot$진단센서 기술과 IT(정보기술)를 이용한 IT화 대응 변압기 유지보수지원시스템을 개발하여 공장내의 실(實)변압기에 설치, 실용성을 확인하였다. 이 시스템은 기존의 광역네트워크를 사용하여 유지보수거점에 위치하면서 원격지의 변압기 운전상태와 감시$\cdot$진단정보를 필요에 따라 액세스할 수 있도록 되어 있으며, 유지보수거점에서는 기기감시서버내의 데이터와 화면을 임의로 액세스할 수 있고 유지보수정보의 공유화와 이상검출시의 유중가스센서의 기동, 부하시 탭전환장치(LTC)의 토크파형 표시에 의한 조기대응과 이상해석$\cdot$진단정도(精度)의 향상에 효과를 발휘할 수 있다. 시스템은 변압기의 중요성, 토털코스트에 맞추어 구축된다. 이 때문에 센서, 각 장치간의 데이터 전송에 대해서는 온라인, 오프라인 및 각종 I/F를 준비하여 시스템의 선택성$\cdot$확장성을 고려토록 하고 있다. 차후 IT화 대응 유지보수지원시스템이 변압기 운전신뢰성 유지와 유지보수코스트 삭감에 효과를 발휘할 것으로 기대한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.7
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• pp.914-919
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• 2004

When the motor is rotating, the torque and rpm are varying as the loads or the driving status connecting through reduction units are changing. On the contrary, one can monitor the changes of the loads or the driving status in the manner of measuring motor torque and rpm. There is a torque measuring method using the strain gauge and bridge circuit. But, because this is the contact method, it has the life time which is dependent on rotating velocity and used time. So this system demands on replacement of some Parts or whole system itself for maintenance. And this system is also relatively big and expensive, requiring preceding annoying process. In this paper, we are going to suppose non-contact method to measure torque and rpm using the Hall effects sensor For this we have made the planetary geared reduction motor with Hall sensors and with the monitoring system. The monitoring system displays the sensing data(torque, rpm) and calculated data( power) and also has the network capability with Bluetooth protocol. Our solution is much more inexpensive ;md simple method to measure torque and rpm than before.

• Tribology and Lubricants
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• v.28 no.3
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• pp.130-135
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• 2012

This study presents a new methodology for realtime tool breakage detection by sensor fusion concept of two hall sensor and an acoustic emission (AE) sensor. Spindle induction motor torque of CNC Lathe during machining is estimated by two hall sensor. Estimated motor torque instead of a tool dynamometer was used to measure the cutting torque and tool breakage detection. A burst of AE signal was used as a triggering signal to inspect the cutting torque. A significant drop of cutting torque was utilized to detect tool breakage. The algorithm was implemented on a NI DAQ (Data Acquisition) board for in-process tool breakage detection. The result of experiment showed an excellent monitoring capability of the proposed tool breakage detection system. This system is available tool breakage monitoring through internet also provides this system's user with current cutting torque of induction motor.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.10
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• pp.184-193
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• 2001

In vector control technique, stator currents of an induction motor are transformed to equivalent d-q currents in a reference frame consist of d and q axis, each of which is coincide with flux and torque direction respectively. Since the current in q-axis is related to the torque in a synchronously rotating frame, torque is estimated as a function of q-axis current and flux. In this paper, a method to estimate torque of an induction motor based on the measurement of 3-phase currents and rotating velocity of a rotor is presented. Graphic-programming is used to measure signals, to estimate the torque and to show the result in the form of user friendly graph in window environment. To stabilize the fluctuation of estimated torque caused from the small measurement error of the rotor velocity, the stator current is reconstructed in a program based on measured signals. The experimental results executed under the velocity of 500 rpm, 1500 rpm without load and 1500 rpm with load show that the proposed method estimates the torque very well.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.319-322
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• 1997

In vector control technique, stator currents of an induction motor are transformed to equivalent d-q currents in reference frame consist of d and q axis, each of which is coincide with flux and torque direction respectively. In this paper, the new algorithm is suggested where the stator current through an induction motor torque is monitored by using a vector control method where an additional equipment is not need. The G-programming is used to apply the suggested algorithm in the experiment and this is applied to an actual system to monitor the torque value of an induction motor on real time. To solve the vibration trouble of estimated torque caused from an unbalanced real rotating speed of an induction motor and measured rotating speed by suggesting the reconstructed in a method based on measurement current signal. This produced system testifies an accuracy of an induction motor through the experiment by comparing the reference value of the control method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.596-602
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• 2001

본 논문에서는 중수로 원자력발전소에서 사용되는 핵연료 교환기 브리지의 상태를 감시하는데 필요한 진단 방법을 도출하였다. 핵연료 교환기는 고방사능 지역에서 작동하기 때문에 신호의 취득은 원격에서 비침투적으로 이뤄져야한다는 제약이 있다. 따라서 비침투적으로 원격에서 측정 가능한 신호들이 선정되었고 선정된 신호를 이용하여 정확한 진단을 위해서 필요한 여러 가지 진단 신호들의 장단점을 비교하였다. 진단 신호로는 모터의 출력 토크를 선정하였고 진단 신호의 타당성을 모형 브리지를 대상으로 수행한 실험을 통하여 검증하였다. 그리고 마지막으로 다양한 환경에서 실험을 하여 브리지의 작동 특성과 결함과 진단 신호와의 관계를 살펴보았다.