• Title/Summary/Keyword: resistance induction

Search Result 632, Processing Time 0.038 seconds

Bending Fatigue Strength of Carburized and Induction Hardened Gears (침탄 및 고주파 열처리한 치차의 굽힘피로강도 평가)

  • Kim, W.D.;Choi, B.I.;Han, S.W.;Kim, J.H.
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.2 no.6
    • /
    • pp.1-8
    • /
    • 1994
  • To enhance the strength of gears for transmission, Generally caburizing heat treatment is applied. But there are some problems in this technology the distortion of gears during heat treatment process, and the discontinuity of manufacturing process. For these reasons, the high frequency induction hardening process is widely used. This method is one of the surface hardening process to improve the wear resistance and fatigue life of the machine components. In this study, to compare the bending fatigue strength of caburized gear with that of induction hardened gear, bending fatigue testing of gears with two different cases was performed by using an electrohydraulic servo-controlled fatigue testing machine and double tooth bending fatigue test fixture. Fatigue life distributions at constant stress levels were established directly from fatigue data. For gear design, the fatigue strength distribution at specified life is more important. This distribution is obtained by statical transformation from fatigue life distribution. Reliability of bending fatigue strength was estimated by P-S-N curves and Weibull distribution.

  • PDF

Adaptive Output Feedback Speed Control of Induction Motorswith Uncertain Rotor Resistance and Load Torque

  • Hwang, Young-Ho;Yang, Hai-Won;Kim, Hong-Pil;Kim, Hyung-Joong
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2002.10a
    • /
    • pp.64.4-64
    • /
    • 2002
  • $\textbullet$ Contents 1 Introduction $\textbullet$ Contents 2 Problem Statement $\textbullet$ Contents 3 Adaptive Output Feedback Control Design $\textbullet$ Contents 4 Stability analysis $\textbullet$ Contents 5 Simulation Result $\textbullet$ Contents 6 Conclusions

  • PDF

Molecular Mechanism of Copper Resistance in Pseudomonas syringae pv. tomato.

  • Cha, Jae-Soon;Donald A. Cooksey
    • Proceedings of the Korean Society of Plant Pathology Conference
    • /
    • 1995.06b
    • /
    • pp.97-117
    • /
    • 1995
  • Copper resistance in Pseudomonas syringae pv. tomato is determined by copper-resistance operon (cop) on a highly conserved 35 kilobase plasmid. Copper-resistant strains of Pseudomonas syringae containing the cop operon accumulate copper and develop blue clonies on copper-containing media. The protein products of the copper-resistance operon were characterized to provide an understanding of the copper-resistance mechanism and its relationship to copper accumulation. The Cop proteins CopA (72 kDa), CopB (39 kDa), and CopC (12 kDa) were produced only under copper induction. CopA and CopC were periplasmic proteins and CopB was an outer membrane protein. Leader peptide sequences of CopA, CopB, and CopC were confirmed by amino-terminal peptide sequencing. CopA, CopB, and CopC were purified from strain PT23.2, and their copper contents were determined. One molecule of CopA bound 10.9${\pm}$1.2 atoms of copper and one molecule of CopC bound 0.6${\pm}$0.1 atom of copper. P. syringae cells containing copCD or copBCD cloned behind the lac promoter were hypersensitive to copper. The CopD (32 kDa), a probable inner membrane protein, function in copper uptake with CopC. The Cop proteins apparently mediate sequestration of copper outside of the cytoplasm as a copper-resistance mechanism.

  • PDF

A Study on the Electrical Characteristics with Design Parameters in GaN Power Static Induction Transistor (GaN Power SIT의 설계변수에 따른 전기적 특성변화에 관한 연구)

  • Oh, Ju-Hyun;Yang, Sung-Min;Jung, Eun-Sik;Sung, Man-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.23 no.9
    • /
    • pp.671-675
    • /
    • 2010
  • Gallium nitride (GaN), wide bandgap semiconductor, has attracted much attention because they are projected to have much better performance than silicon. In this paper, effects of design parameters change of GaN power static induction transistor (SIT) on the electrical characteristics (breakdown voltage, on resistance) were analyzed by computer simulation. According to the analyzed results, the optimization was performed to get power GaN SIT that has 600 V class breakdown voltage. As a result, we could get optimized 600 V class power GaN SIT that has higher breakdown voltage and lower On resistance with a thin (a several micro-meters) thickness of the channel layer.

A Drive Strategy of Induction Motor for High Accuracy position Control of Elevator (엘리베이터의 정밀위치제어(精密位置制御)를 위한 유도전동기(誘導電動機) 구동방법(驅動方法))

  • Yoon, Byung-Do;Kim, Yoon-Ho;Jung, Jae-Youn;Chae, Soo-Hyung;Kim, Choon-Sam
    • Proceedings of the KIEE Conference
    • /
    • 1992.07b
    • /
    • pp.1215-1217
    • /
    • 1992
  • This Paper described the hish performance position control for elevator using induction motor and driver. In this paper, the suitable Motor specifications for elevator drive are briefly discussed and high accuracy position control for both kinds of control method is analysed considering the parameter variation in the primary and secondary resistances. Since the pre-identified values of the motor constants are used to determine the control inputs, the performance degradation is caused by the parameter variation such as in the motor resistance. Particularly, the value of secondary resistance is considered significant because the control gain to determine the slip frequency is heavily dependent on that. The new proposed method uses on special small input signal for the parameter indentification and is expected to have the high accuracy position.

  • PDF

Synthesis of SiC Nano-powder from TEOS by RF Induction Thermal Plasma (RF 열플라즈마를 이용한 TEOS로 부터의 SiC 나노분말 합성)

  • Ko, Sang-Min;Koo, Sang-Man;Kim, Jin-Ho;Kim, Ji-Ho;Byeon, Myeong-Seob;Hwang, Kwang-Taek
    • Journal of the Korean Ceramic Society
    • /
    • v.48 no.1
    • /
    • pp.1-5
    • /
    • 2011
  • Silicon carbide (SiC) has recently drawn an enormous industrial interest because of its useful mechanical properties such as thermal resistance, abrasion resistance and thermal conductivity at high temperature. RF Thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) has been utilized for synthesis of high purity SiC powder from cheap inorganic solution (Tetraethyl Orthosilicate, TEOS). It is found that the powders by thermal plasma consist of SiC with free carbon and amorphous silica ($SiO_2$) and, by thermal treatment and HF treatment, the impurities are driven off resulting high purity SiC nano-powder. The synthesized SiC powder lies below 30 nm and its properties such microstructure, phase composition, specific surface area and free carbon content have been characterized by X-ay diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric (TG) and Brunauer-Emmett-Teller (BET).

A Robust MRAC-based Speed Estimation Method to Improve the Performance of Sensorless Induction Motor Drive System in Low Speed (저속영역에서 센서리스 벡터제어 유도전동기의 성능을 향상시키기 위한 MRAC 기반의 강인한 속도 추정 기법)

  • 박철우;권우현
    • The Transactions of the Korean Institute of Electrical Engineers B
    • /
    • v.53 no.1
    • /
    • pp.37-46
    • /
    • 2004
  • A novel rotor speed estimation method using model reference adaptive control(MRAC) is proposed to improve the performance of a sensorless vector controller. In the proposed method, the stator current is used as the model variable for estimating the speed. In conventional MRAC methods, the relation between the two model errors and the speed estimation error is unclear. In the proposed method, the stator current error is represented as a function of the first degree for the error value in the speed estimation. Therefore, the proposed method can produce a fast speed estimation. The robustness of the rotor flux-based MRAC, back EMF-based MRAC, and proposed MRAC is compared based on a sensitivity function about each error of stator resistance, rotor time constant, mutual inductance. Consequently, the proposed method is much more robust than the conventional methods as regards errors in the mutual inductance, stator resistance. Therefore, the proposed method offers a considerable improvement in the performance of a sensorless vector controller at a low speed. In addition, the superiority of the proposed method and the validity of sensitivity functions were verified by simulation and experiment.