• 조명전기설비학회논문지
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• 제29권7호
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• pp.38-46
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• 2015

This paper propose a variable parameter estimations for variable over current load of five-phase squirrel-cage induction motor(IM) to servo control system. In order to high performance control of AC motor using a field oriented control(FOC) and direct torque control(DTC) algorithm, there are required precise motor parameters for slip calculation, flux observer, controller gain, torque command of current components, rotor position, speed estimation, and so on. We are suggest a analyzed estimation results of the motor parameters that developing five-phase squirrel-cage IM have a stator of concentrated winding for experimental within variable over current load at rated input frequency. There are results of stator winding measurement, no-load test, locked-rotor test, variable over current load test, and estimated parameters of equivalent circuits using manufactured experimental apparatus by IEEE Standard Test Procedure for Polyphase Induction Motors and Generators 112-2004.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1111-1113
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• 2000

This paper presents the calculation method for the equivalent-circuit parameters and torque characteristics of squirrel-cage induction motors. The measurement of motor parameters were calculated by the stator resistance test, the blocked rotor test and no load test to T type equivalent-circuit. Especially, this paper describes the test results obtained by using hall sensor and strain gauge for the current and torque characteristics of induction motors. Three-phase squirrel-cage induction motor which has 1[hp] was used to the test and the parameters obtained by the test were compared with the maker parameters.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.295-298
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• 1997

In large system, design margin makes relatively price higher. So, optimal design through exact analysis of thermal behavior is needed. In this paper, we propose the equivalent load test facility using two inverter & converter system and inductors. Applying actual electrical profiles for motor drive, thermal characteristics of power converter fed AC motor drive are obtained, and the results are compared with simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1155-1158
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• 2000

This paper presents characteristics calculation method which do not need measurement and test results. This paper draws out every motor parameters for fundamental and harmonic frequencies from the given motor demensions, and presents new equivalent circuits. Using this new equivalent, this paper performs characteristics simulations, and this paper shows that the simulation results agree well with walues obtained obtained by actual load test.

• 품질경영학회지
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• 제23권4호
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• pp.52-57
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• 1995

Testing problem of equality between two linear regressions is considered. Chow test is discussed and likelihood ratio test(LR test), F-test and Score test are derived. Score test are compared with other tests and show they are asymptotically equivalent.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.1928-1934
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• 2014

Induction motors are widely used due to their rugged, robust and easy to care features. Since they are heavily used in industry, testing of three phase induction motors have play a vital role. In order to determine motor equivalent circuit parameters, efficiency of motor, squirrel caged laboratory sized an induction motor test setup is prepared. It is suitable for the induction motor with the frame size of 100 and 112. A virtual Instrumentation typed engineering workbench (called as LabVIEW) software packet, is utilized as a graphical user interface program. Motor input power is measured by measuring the input voltage, current and power factor with the help of hall effect typed voltage and current transformers. Also, the output power is measured by measuring the speed and torque with the help of an encoder and torque sensor. All outputs of the voltage and current transformer, encoder and temperature, torque sensors are given to the Data Acquisition Card (DAQ) which acquires the data for processing and then the equivalent circuit parameters, efficiency, performance and loading characteristics are found out, using LabVIEW based user interface. It is suggested to use this test rig for the quality control of produced motors in industry, and an educational experiment setup in the school laboratories.

• 전기학회논문지P
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• 제57권2호
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• pp.153-159
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• 2008

We have developed an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) without any precise standard CT by measuring four parameters in a CT equivalent circuit. The excitation admittance in the CT equivalent circuit can be obtained by employing standard resistors with negligible reactive component. The secondary leakage impedance in the CT equivalent circuit can be measured using a universal impedance bridge. The method was applied to CTs under test with the wide current ratios in the range of 5 A / 5 A - 5,000 A / 5 A and 5 A / 1 A - 5,000 A / 1 A. The ratio error and phase displacement of the CT under test obtained in this study are consistent with those measured at the national institute in Canada using the same CT under test within an expanded uncertainty (k = 2) in the overall current ratios.

• 대한전기학회논문지:전력기술부문A
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• 제52권11호
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• pp.632-638
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• 2003

Modern power systems are very complex and to model them completely is impractical for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of frequency dependent equivalent. The s-domain rational function form of frequency dependent equivalent does not need refitting if the simulation time-step is changed in the electromagnetic transient program. This is because the s-domain rational function coefficients are independent of the simulation time-step, unlike the z-domain rational function coefficients. S-domain rational function fitting techniques for representing frequency dependent equivalents have been developed using Least Squares Fitting(LSF). However it does not suffer the implementation error that exited in this work as it ignored the instantaneous term. This paper Presents the formulation for developing 1 Port Frequency Dependent Network Equivalent(FDNE) with the instantaneous term in S-domain and illustrates its use. This 1 port FDNE have been applied to the CIGRE Benchmark Rectifier test AC system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the 1 port (FDNE) developed with Thevenin and Norton Equivalent network. The study results have indicated the robustness and accuracy of 1 port FDNE for electromagnetic transient studies.

• Journal of Welding and Joining
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• 제31권6호
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• pp.112-118
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• 2013

In this study, constant loading test (CLT) was performed to evaluate the hydrogen embrittlement resistance for multipass FCA weld metals of 600MPa tensile strength grade. The microstructures of weld metal-2 having the smallest carbon equivalent (Ceq=0.37) consisted of grain boundary ferrite and widmanstatten ferrite in the acicular ferrite matrix. The weld metal-1 having the largest Ceq=0.47, showed the microstructures of grain boundary ferrite, widmanstatten ferrite and the large amount of bainite (vol.%=19%) in the acicular ferrite matrix. The weld metal-3 having the Ceq=0.41, which was composed of grain boundary ferrite, widmanstatten ferrite, and the small amount of bainite (vol.%=9%) in the acicular ferrite matrix. Hydrogen desorption spectrometry (TDS) used to analyze the amount of diffusible hydrogen and trapping site for the hydrogen pre-charged specimens electrochemically for 24 hours. With increasing the current density of hydrogen pre-charging, the released amount of diffusible hydrogen was increased. Furthermore, as increasing carbon equivalent of weld metals, the released diffusible hydrogen was increased. The main trapping sites of diffusible hydrogen for the weld metal having a low carbon equivalent (Ceq=0.37) were grain boundaries and those of weld metals having a relatively high carbon equivalent (Ceq: 0.41~0.47) were grain boundaries and dislocation. The fracture time for the hydrogen pre-charged specimens in the constant loading test was decreased as the carbon equivalent increased from 0.37 to 0.47. This result is mainly due to the increment of bainite that is vulnerable to hydrogen embrittlement.

• 대한토목학회논문집
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• 제30권2A호
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• pp.121-129
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• 2010

본 연구에서는 고감쇠 고무받침 시험체의 다양한 특성실험을 통하여 전단특성 의존성을 파악하였다. 파악하고자 하는 고감쇠 고무받침의 특성은 변위의존성, 면압 의존성, 주파수 의존성, 온도 의존성 등이다. 특성실험결과 고감쇠 고무받침의 특성치는 온도에 가장 큰 영향을 받는 것으로 나타났으며, 주파수가 증가할수록 전단강성과 등가감쇠비 모두 증가하나 반복횟수가 증가 할수록 고무의 온도상승으로 인하여 그 값들은 감소하였다. 그리고 면압이 증가할수록 유효강성은 감소하고 등가감쇠비는 증가하는 것으로 타나났다. 본 실험결과에 의하면 고감쇠 고무받침의 설계의 주요한 변수인 전단강성과 등가감쇠비를 산정함에 있어 설계변위와 가진속도 및 온도의 면밀한 검토가 필요하다고 판단된다.