• Title/Summary/Keyword: loss frequency

Search Result 3,544, Processing Time 0.036 seconds

A Study on Insulation Degradation Properties of Thermal Conductive Silicone Rubber due to Temperature Transition (온도 변화에 의한 열전도성 실리콘 고무의 절연 열화 특성)

  • Lee, Sung Ill
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.7
    • /
    • pp.456-461
    • /
    • 2015
  • In this study, the frequency properties of electrostatic capacity and dielectric loss for the samples with different types of filler has been measured in through the applied frequency range of 7 kHz ~3,000 kHz at temperature of $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$, $170^{\circ}C$. The results of this study are as follows. When the sample is degradated at the temperature of $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$, $170^{\circ}C$ and the frequency range of 7 kHz ~3,000 kHz is applied, It found that the electrostatic capacity of the sample with Polyimide film is larger than the sample with Grass fiber. It found that the dielectric loss for the sample with Polyimide film is larger than the sample with Grass fiber with increasing frequency and temperature in the $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$, $170^{\circ}C$ range. Also, the dielectric loss decreased with increasing frequency. In case of the sample with Polyimide film, It found that the electrostatic capacity decreased with increasing temperature, and the dielectric loss gradually decreased with increasing frequency.

Low Loss Frequency Doubler for RFID (RFID용 저손질 주파수 체배기)

  • Kim, JIn-Su;Hwang, Hee-Yong
    • Journal of Industrial Technology
    • /
    • v.28 no.A
    • /
    • pp.177-184
    • /
    • 2008
  • A low loss frequency doubler operated on low power for the RFID harmonic tags is presented. Using the excellent nonlinear characteristics of the Schottky barrier diode and proper matching networks between the diode and ports, the low conversion loss of the harmonic tag is accomplished. This doubler could be used to increase the detectable distance of the conventional RFID system adopted harmonic tags.

  • PDF

Calculation of Loss of Load Expectation and Loss of Load Frequency using a Moment matching method (모멘트 대입법에 의한 전력부족 기대치와 빈도수의 산정)

  • Yoo, Hyun-Ho;Kim, Jin-O
    • Proceedings of the KIEE Conference
    • /
    • 1998.07c
    • /
    • pp.1076-1078
    • /
    • 1998
  • This paper proposes a new approach for calculating frequency and duration by using the moment matching technique. Two separate expressions are derived, one for the loss of load expectation(LOLE) and the other for the loss of load frequency(LOLF). These expressions are combination of exponentials and are therefore easily integrable and can be readily evaluated. The proposed approach is quite comparable of with the other methods at the aspect of accuracy and efficiency.

  • PDF

Frequency Dependence of High-Frequency Bottom Reflection Loss Model (주파수 종속성을 갖는 고주파 해저면 반사손실 모델)

  • 박순식;윤관섭;나정열;석동우;주진용;조진석
    • The Journal of the Acoustical Society of Korea
    • /
    • v.23 no.5
    • /
    • pp.362-369
    • /
    • 2004
  • The High-frequency (30 ∼ 120 ㎑) bottom reflection loss at rough water-sediment interface is affected by the gram size distribution of the sediments. The roughness of the bottom surface is represented by "acoustical roughness. g/sub R/" The grain size of sandy sediments is g/sub R/∼O(1) and the dependence as a function of frequency. We suggest the modified bottom reflection loss model (HYBRL model , HanYang university Bottom Reflection Loss model) that include in the deviation of the reflection loss as a function of the grain size distribution and frequency dependence. And bottom reflection loss model of frequency dependence and deviation of bottom properties is verified by water tank and field experiments.

Estimation of the Expected Loss per Exposure of Export Insurance using GLM (일반화 선형모형을 이용한 수출보험의 지급비율 추정)

  • Ju, Hyo Chan;Lee, Hangsuck
    • The Korean Journal of Applied Statistics
    • /
    • v.26 no.6
    • /
    • pp.857-871
    • /
    • 2013
  • Export credit insurance is a policy tool for export growth. In the era of free trade under the governance of WTO, export credit insurance is still allowed as one of the few instruments to increase exports. This paper, using data on short-term export insurance contracts issued to foreign subsidiaries of Korean companies, calculates the expected loss per exposure by combining the effect of risk factors (credit rate of foreign importers, size of mother company, and payment period) on loss frequency and loss severity in different levels. We, applying generalized linear models (GLM), first fit loss frequency and loss severity to negative binomial and lognormal distribution, respectively, and then estimate the loss frequency rate per contract and the ratio of loss severity to coverage amount. Finally, we calculate the expected loss per exposure for each level of risk factors by combining these two rates. Based on the result of statistical analysis, we present the implication for the current premium rate of export insurance.

Comparison of iron loss characteristics between thin-gauged grain-oriented 3% Si-Fe sheets and commercial 0.3 mm-thick grain-oriented electrical sheets (극박 방향성 규소강판과 상용 방향성 규소강판의 철손특성 비교)

  • Cho, Seong-Soo;Kim, Sang-Beom;Soh, Joon-Young;Chae, U-Gyu;Han, Sang-Ok
    • Proceedings of the KIEE Conference
    • /
    • 2009.07a
    • /
    • pp.2009_2010
    • /
    • 2009
  • Thin-gauged 3% Si-Fe sheets having a high magnetic induction of over 1.9 T have been developed for the purpose of applications where operation frequency is higher than power frequency. In order to clarify requirements of iron loss characteristics for the applications, iron loss characteristics of the newly developed strip were investigated by iron loss separation method and were compared with those of commercially produced 0.3 mm-thick electrical sheets. In case of relatively high excitation induction(1.7 T) and low frequency(60 Hz), reducing hysteresis loss is effective to decrease total iron loss. In case of relatively low excitation induction(1.0 T) and high frequency(1 kHz), reducing eddy-current loss is effective by decreasing thickness and grain size to improve total iron loss.

  • PDF

Analysis of Eddy Current Loss in Brushless DC Motor according to the Swiching Frequency of the PWM Inverter (PWM 인버터의 스위칭 주파수에 따른 브러시레스 DC 모터에서의 와전류 손실 특성 해석)

  • Kim, Wa-Sung;Choi, Tae-Sik;Kim, Youn-Hyun;Lee, Ju
    • Proceedings of the KIEE Conference
    • /
    • 2000.07b
    • /
    • pp.675-677
    • /
    • 2000
  • In the paper the eddy current loss in brushless DC motor due to switching frequency supplied by PWM inverter, is analyzed. The compensated conductivity is used in order to analyze the eddy current loss in brushless DC motor which has lamination structure. The eddy current loss is deceased when switching frequency supplied by PWM inverter is gradually increased from 1.2kHz up to 12kHz. The high switching frequency of PWM inverter make the output wave into a similar sine wave and this leads to the decreasing eddy current loss.

  • PDF

A Study on Properties of C-V Degradation due to Heating in Teflon (테프론의 가열에 의한 C-V 열화 특성에 관한 연구)

  • Lee, Sung Ill
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.27 no.11
    • /
    • pp.730-735
    • /
    • 2014
  • In this study, the temperature characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film which is degradated at the $120^{\circ}C{\sim}200^{\circ}C$ temperature range in the oven for 10 hours has been measured in through the applied frequency range of 0.1 kHz~4,800 kHz at temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Also, in the same conditions, the frequency characteristics of electrostatic capacity and dielectric loss for the sample of Teflon film has been measured in through the applied temperature range of $30^{\circ}C{\sim}70^{\circ}C$ on setting frequency of 0.1 kHz, 1 kHz, 10 kHz, 100 kHz. The results of this study are as follows. When the frequency range of 0.1 kHz~4,800 kHz applied to the sample of Teflon film, the electrostatic capacity has been measured at the temperature of $50^{\circ}C$, $90^{\circ}C$, $130^{\circ}C$, $170^{\circ}C$. Through this measurement, it found that the electrostatic capacity decreased with increasing temperature. Regarding this result, may be it is because the electromagnetic coupling is degraded by thermal degradation. When the sample of Teflon film heated at $280^{\circ}C$ for 10 hours in oven, the dielectric loss has changed from unstable status to stabilizing status with increasing the degradation temperature in the $120^{\circ}C$, $160^{\circ}C$, $200^{\circ}C$ range. In this measurement, the two spectrums of dielectric loss appeared. It considers that this spectrum of dielectric loss appeared in 300 Hz is caused by the molecular motion of the C-F or OH group. Through this study, It found that the electrostatic capacity decreased with increasing frequency and temperature, and there is no change in dielectric loss, although the frequency increases.

Complex Compliance of Rough Rice Kernel under Cyclic Loading (주기적(週期的) 반복하중(反復荷重)을 받는 벼의 복소(複素)컴프라이언스)

  • Kim, M.S.;La, W.J.;Park, J.M.
    • Journal of Biosystems Engineering
    • /
    • v.17 no.1
    • /
    • pp.79-90
    • /
    • 1992
  • Viscoelastic characteristics of agricultural products may be determined through three basic tests ; stress relaxation, creep, and dynamic test. Considering the changeability of living materials, dynamic test in which information is derived in a relatively short time appears to be highly desirable, in which either cyclic stress or cyclic strain is imposed and the remaining quantity (strain or stress) is measured. The periodically varying stress will also result in periodically varying strain which in a viscoelastic material should theoretically be out of phase with the stress, because part of the energy subjected to sample is stored in the material as potential energy and part is dissipated as heat. This behavior results in a complex frequency-dependent compliance denoted by J($i{\omega}$). The complex compliance and therefore the storage compliance, the loss compliance, the phase angle, and percent energy loss for the sample should be obtainable with a given static viscoelastic property of the material under static load. The complex compliance of the rough rice kernel were computed from the Burger's model describing creep behavior of the material which were obtained in the previous study. Also, the effects of cyclic load and moisture content of grain on the dynamic viscoelastic behavior of the samples were analyized. The results obtained from this study were summarized as follows ; 1. The storage compliance of the rough rice kernel slightly decreased with the frequency applied but at above the frequency of 0.1 Hz it was nearly constant with the frequency, and the loss compliance of the sample very rapidly decreased with increase in the frequency on those frequency ranges. 2. It was shown that the storage compliance and the loss compliance of the sample increased with increase in grain moisture content. Effect of grain moisture content on the storage compliance of the sample was highly significant than effect of the frequency applied, but effect of the frequency on the loss compliance of the sample was more significant than effect of grain moisture content. 3. In low moisture content, the percent energy loss of Japonica-type rough rice was much higher than that of Indica-type rough rice, but, in high moisture content, vice versa.

  • PDF

Characteristics of Isolator for material parameter (페라이트 소재변수에 따른 아이솔레이터 특성 연구)

  • Jun, Dong-Suk;Lee, Hong-Yeol;Kim, Dong-Young;Lee, Sang-Seak
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2003.07a
    • /
    • pp.119-122
    • /
    • 2003
  • This paper describes characteristics for insertion losses of Isolator have an effect on material parameter. One purpose of the paper is to present insertion loss on this resonator for magnetic loss, dielectric loss, magnetic field and saturation magnetization. Another is to study the effect of propeller resonator on response characteristics. In this paper, the analysis and measurement of the response characteristics were carried out for the isolator prototype. The measurement results agreed on the simulation results and acquire insertion loss $0.18\;{\sim}\;0.24dB$, return loss 27dB, isolation 27dB and bandwidth 500MHz on this condition saturation magnetization 550G, dielectric loss 0.0004, magnetic loss 20 and dielectric constant 14.

  • PDF