체결토크 및 진동에 따른 접촉불량에 의한 Electric Fan의 전기적 특성 분석

엄한얼 충북대학교 2022 국내석사

본 연구에서는 Electric Fan에 대하여 접촉부에서 발생하는 접촉불량이 기계·기구에 미치는 영향을 파악하기 위하여 접촉불량 모듈을 만들었으며, Electric Fan 실험을 통하여 전류 및 온도 특성을 분석하였다. Electric Fan의 모터를 연구 대상으로 선정하였고, 접촉부에서 발생한 아크 전류가 모터에 미치는 영향을 실험을 통해 확인하였다. 진동 기계·기구의 진동발생기 출력과 접촉부 체결토크에 따라 변화하는 아크 전류 및 온도를 측정하기 위하여 출력 범위를 360 ∼ 3600W로 하였으며 10단계로 구분하여 실험하였다. 또한 풍속계를 통하여 모터의 출력 및 효율을 측정하였다. 실험값을 아크로 인한 전류값과 전력값을 연구한 선행 연구를 기준으로 하여 정상상태와 접촉불량 상태를 비교하였다. 이를 통하여 모터에서 발생하는 전기적 이상신호 및 오작동을 통해 접촉불량으로 인한 아크전류의 문제점을 제시하였다. 구체적인 내용은 다음과 같다. 실험을 통해 정상상태와 접촉불량 상태의 전기적 이상신호를 분석한 결과, 접촉부 체결토크가 작아질수록 동일 출력에서 아크전류값이 선형적으로 감소하였으며, RMS는 최대 70%까지 하락하는 값을 보였다. 정상상태와 접촉불량 상태의 오동작을 분석한 결과 온도는 최대 20℃상승하였고, 풍속은 접촉불량에서 정상상태와 비교하여 최대 22% 하락하였다. 또한 0.5kgf의 토크에서 2400W 이상의 출력을 주었을 때 전원라인이 단선되어 모터 출력이 90% 감소하는 값을 보이며 정상적인 작동이 불가하였다. 접촉부 탈락 및 배선의 단선이 진행된 상태이기에 즉시 기기 정지 및 전원차단 후 전기적 접촉부를 점검해야한다. 본 연구에서 접촉불량 상태의 전기적 이상신호인 전류패턴과 RMS와 오동작인 풍속 감소값을 제시하였으며, 이를 통해 접촉불량을 미연에 찾아내어 다중이용업소와 공장의 Electric Fan 고장과 화재를 예방할 수 있는 기준을 제시하였다. This thesis created a module having contact failure to identify the effects of such a failure, which occurs in the contact area of a electric fan, on such machinery and analyzed the characteristics of the currents and temperatures in an experiment. For the experiment, the range of the electric output was set from 360 to 3600W, which was classified into 10 steps, to measure the arc current and temperature that changed depending on the power output of the vibrator and on the tightening torque of vibratory machinery and equipment. In addition, the output and efficiency of the motor employed were measured with an anemometer. The values produced from the experiment were compared with those from the previous studies on the current and power values induced by arc to see if they were in normal range or indicating contact failure. As a result, this thesis estimated that arc currents, triggered by contact failure, were problematic based on abnormal electrical signals and defects detected in the motor. Here are the details: an comparative analysis on the electrical signals witnessed in case of proper contact or contact failure indicated that the smaller the fastening torque of the contact area got, the linearly smaller the arc current value became at the same output, with RMS being reduced by up to 70 percent. A comparison between the normal operational status and defects caused by loose contact showed that the temperature went up to 20℃ and the wind speed declined by up to 22 percent when the contact was improper. Furthermore, the supply of the power output of more than 2400W at the torque of 0.5kgf reduced the motor output by 90 percent, making it impossible to operate. As the contact area fell off from the original position and the wire was cut, the machine or equipment should be stopped immediately with its power being cut off and the electrical contact area should be inspected. This thesis proposed the current pattern and RMS, the two indicators of contact failure, as well as the size of reduction in air volume, an indicator of defects, and suggested standards to prevent failures and fires at electric fan by detecting loose contact in advance.

해상용 고휘도 LED 등명기의 방열 시스템 개발에 관한 연구

임민석 한국해양대학교 해사산업대학원 2013 국내석사

In the Korean coast and approaches many types of light aids to navigation have been installed and been operated to guide vessels into fairways, channels, or harbours safely and to identify the hazards to navigation. Because the aids to navigation lights give the information of their position, the lamps of them are not heavy and driven with a low electric power and their luminous intensity has to be more than the given value. In the past the electric bulbs were used as the sources of light. The disadvantage of them is that they have are usually replaced by new ones frequently and also need a high electric power. Because of this the LEDs have been introduced and have the advantage of a long life and low power. The problem is that they are not suitable for the lamps with a high luminous intensity. Nowadays the aids to navigation lights need LED lamps with a high luminous intensity of more than 1 W. The demerit of the high intensity LED is that it consumes a high power and also radiates a high heat which drops its intensity and reduces its lifespan. This paper is to develop the thermal management or cooling system in the LED lamp with high luminous intensity of more than 1 W to solve the problem of high heat, The target of the system is to maintain the temperature of less than 50 ℃ and the luminous intensity of 1500 cd. The high temperature of more than 50℃ causes the deterioration of luminous intensity and the reduction of the lifetime of LED lights. The procedure of developing the system is done as follows. Firstly, this paper is to develop two types of heat sink, considering the enclosed structure of the maine lamp, limited supply of electric power, weight and size. The heat radiation of the two heat sinks are examined by simulation respectively. And then through experimental test they are investigated again. The result shows a temperature of 62.2 ℃ in the junction of the LED. Secondly, to drop the temperature the cooling fan is added to the heat sink. The heat radiation of the cooling system by a fan is examined through simulation as similarly as in the heat sink. And also the experimental test is carried out. The result shows that the LED light keeps temperature of some 34 ℃ and works satisfactorily. However the cooling system has a disadvantage of additional power for driving the cooling fan. To minimize the consumption of power the control circuit of on-off method is devised. The paper is to limit the heat sink, only two types of it and the material of aluminum. It means that the thermal management is not sufficient. We can consider the heat pipe instead of heat sink, various types heat sink of different fin intervals, and other material like copper. These will be dealt with in the future study.

가정용 전기기기 적합성 평가의 측정 신뢰도 향상을 위한 표준 모형 제시 연구

이창민 연세대학교 공학대학원 2013 국내석사

본 연구에서는 가정용 전기제품 적합성 평가의 대표적인 측정항목인 소비전력 및 저항법에 따른 모터권선의 온도상승값에 대한 측정 신뢰도를 높이고자 각 항목별 불확도를 평가하였으며 시험용 샘플은 대표적인 가정용 전기제품인 선풍기를 이용하였다. 전통적인 불확도 계산방법인 GUM(Guide to the expression of uncertainty in measurement)의 GUF(GUM Uncertainty Framework) 외에도 몬테카를로 방법(MCM)을 사용하여 불확도를 계산하고 결과를 비교 분석했다. 특히 불확도 측정의 가장 중요한 요소인 확률밀도함수 선정에 있어서는 반복 측정 항목인 A형 불확도는 소비전력의 경우 은 측정횟수가 30회여서 중심극한정리를 사용하여 정규분포로 결정하였고, 저항법에 의한 모터 권선의 온도상승값은 초기 권선저항 측정값 및 온도포화 후 권선저항 측정값 는 측정횟수가 15회로 정규성 검토를 통해 t-분포로 결정하였다. 다만 비반복 측정 항목인 B형 불확도 요소는 기존의 선험적인 판단에 근거하여 교정성적서의 항목은 정규분포로 제조자에 의해 제공되는 사양은 균일분포로 결정하였다. 소비전력의 측정의 경우 GUF를 통해 계산된 95% 신뢰구간은 42.2755W ~ 42.6845W 였고 MCM을 통해 계산된 95% 신뢰구간은 42.2842W ~ 42.6746W로 약 0.01W의 경미한 차이를 보였다. 또한 저항법에 의한 모터 권선의 온도상승 측정의 경우 전체 모델 함수를 t-분포로 가정하면 GUF를 통해 계산된 95% 신뢰구간은 41.959K ~ 42.651K 였고 MCM을 통해 계산된 95% 신뢰구간은 41.953K ~ 42.650K로 표현되어 역시 약 0.003K의 극히 경미한 차이를 보였다. 한편 GUF 방법은 포함인자 값 및 감도계수를 계산함에 있어서 정확성이 떨어질 확률이 높음을 본 연구를 통해 다시 확인할 수 있었고 MCM의 경우 이러한 계산상의 오류를 없앨 수 있으므로 기존의 전통적인 기법인 GUF대신 MCM을 사용하여 측정의 신뢰성을 보완 또는 대체할 수 있음을 확인하였다.

A Scalable, High-Throughput, and Fine-Pitch Flexible Fan-Out Package for the Advanced Packaging Era

Sabbir, Golam University of California, Los Angeles ProQuest Dis 2025 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Packaging has been a driver for performance scaling in CMOS. Dieletization has been a driver for package scaling with several technology offerings provided at different cost and performance levels: organic packages, silicon interposers, fan-out wafer level packaging (FOWLP) to name just a few. Amongst these fan-out wafer level packaging and fan-out panel level packaging are attractive, cost-effective solutions to heterogeneous integration as compared to monolithic fabrication. The current state-of-the-art for FOWLP as deployed in the semiconductor industry utilizes die-to-die I/O (pad) pitch of 36 µm. The pad pitches that is achievable in fan-out is limited by two factors: die shift and warpage. In this work, we have developed TrueAdapt™, a methodology to fabricate 10 µm (pad) pitch wiring in FOWLP which is scalable (to large area format) and is high-throughput (for high-volume manufacturing). It consists of a suite of techniques: computer vision is used to identify and measure die shift, which is utilized to dynamically adjust the layout. Then, a direct-write laser lithography system is used to adjust the patterning of the wiring layer in real-time. In addition, a novel technique in direct-write laser lithography called focal extension is utilized, which increases the depth of focus (DOF) of laser direct-write. To fully demonstrate the reliability and repeatability of our method, we demonstrate a 25-die daisy-chain assembly using TrueAdapt™ in which all 25 dies are connected at a minimum of 10 µm pad pitch. Furthermore, this demonstration uses the FlexTrate™ platform, which is a flexible FOWLP process utilizing polydimethylsiloxane (PDMS) as the molding compound. We demonstrate, with high yield (100%), the electrical and flexibility results of the daisy chain assembly. We further demonstrate a real-world application in applying TrueAdapt™ to address die-shift in flexible display technology (FlexPlay). We fabricate a 635 pixel per inch (ppi) flexible GaN micro-LED display in the FlexTrate™ with a LED pitch of 40 µm and with two level metallization. A driver die is integrated to complete the flexible display with high yield (>90%) for the approximately 100,000 LEDs.