• 한국음향학회지
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• 제10권3호
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• pp.72-82
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• 1991

3상농형유도전동기에서 발생되는 소음중 자기소음을 해석하였다. JEM-1313 규격과 반확산 음장법을 이용하여 전체의 소음을 측정하였으며, fk={K+$\frac{Z_s}{P}$(1-S)}f[Hz]의 실험식을 도출하였다. 고정자 권선의 자기소음만을 도출하기 위해서 회전자를 제거하고 고정자권선에 정격전압, 정격주파수를 가한 상태에서 자기소음을 측정하여 비교, 검토하는 소음해석방법을 제시하였다. 이론치와 실험치는 1440[Hz], 1560[Hz]에서 근사하였고 가장 큰 자기고조파는 1560[Hz]에서 발생되는 것을 알 수 있다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.498-503
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• 2000

A safety-related equipment for use in Nuclear Power Plant should be needed an Equipment Qualification. This paper presents the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5&6 Nuclear Power Plants. In this paper, the method of qualification is a combination of type test and analysis method, which is composed of Radiation exposure test, Seismic simulation test, Thermal aging analysis for non-metallic materials and Seismic analysis. It is found that the motor performs its safety function with no failure mechanism under postulated service conditions.

• 한국정밀공학회지
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• 제24권6호
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• pp.72-77
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• 2007

A safety-related equipment for the nuclear power plant should be needed an equipment qualification. In this paper, the approach, methods, philosophies, and procedures for qualifying the large squirrel-cage induction electric pump motors for use in ULCHIN 5, 6 Nuclear Power Plants were presented. The method of qualification is a combination of experimental test and analytic method, which is composed of radiation exposure test, seismic simulation test, thermal aging analysis for non-metallic materials, and seismic analysis. The results showed that the motor performed its safety function with no failure mechanism under postulated service conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.929-931
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• 1993

The design sensitivity analysis based on the finite element method is presented for the eddy current problem with a voltage source. Since, in this problem, the complex variable is used as the state variable, new approach to the sensitivity calculation for the complex variable system is required. Its result is applied to the design of the rotor slot shape of squirrel cage induction motor. As a analysis model, only one slot pitch of rotor is analyzed by using a Periodic boundary condition. The use of this minimal modelling method leads to much saving of calculation time. The design objective is to obtain the desired slip-torque characteristic. Because the shape of rotor slot has much influence on the slip torque characteristic, the design variables are taken on the interface shape between rotor core and rotor bar. The initial shape of rotor slot is the trapezoidal type with rounding corners. The obtained final shape is quite similar to the double squirrel cage type.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.665-673
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• 2017

This paper proposes a field weakening control method for operating an induction motor with a variable DC input voltage condition. In the variable DC voltage condition such as a battery, the field weakening method are required for the maximum output power. The conventional field weakening control methods can be used for operating the induction motor over the rated speed in a constant DC-link voltage condition. However, the conventional methods for operating the motor with the variable DC voltage is not suitable for the maximum output power. To overcome this problem, this paper proposes the optimized field weakening control method to extend the operating range of the induction motor with a rated power in a limited thermal and a wide DC input voltage conditions. The optimized d-axis and q-axis current equations are derived according to the field weakening region I and II to extend the operating region. The experimental results are presented to verify the effectiveness of the proposed method.

• Journal of Power Electronics
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• 제11권2호
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• pp.163-172
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• 2011

Oxidation models of a rotor bar and end ring segment in an induction motor are presented to simulate the behavior of an induction machine working with oxidized rotor parts which are modeled as rotor faults in progress. The leakage inductance and resistance of the rotor parts arc different from normal values because of the oxidation process. The impedance variations modify the current density and magnetic flux which pass through the oxidized parts. Consequently, it causes the rotor asymmetry which induces abnormal harmonics in the stator current spectra of the faulty machine. The leakage inductances of the oxidation models are derived by the Ampere's law. Using the proposed oxidation models, the rotor bar and end ring faults in progress can be modeled and simulated with the motor current signature analysis (MCSA). In addition, the oxidation process of the rotor bar and end ring segment can motivate the rotor asymmetry, which is induced by electromagnetic imbalances, and it is one of the major motor faults. Results of simulations and experiments are compared to each other to verify the accuracy of the proposed models. Experiments are achieved using 3.7 kW, 3-phase, and squirrel cage induction motors with a motor drive inverter.

• Journal of Magnetics
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• 제18권2호
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• pp.212-215
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• 2013

This paper deals with torque harmonic characteristics and its reduction design of induction motors for electric vehicle (EV) propulsion. For calculating the stator harmonic flux of squirrel-cage induction motor, the numerical methods have been employed on the structural configuration design of stator and rotor teeth. In particular, torque ripples including spatial harmonics are obtained by Finite Element Method (FEM), and their individual harmonic components are identified with Fast Fourier Transform (FFT). In this paper, design modification on the teeth surface gives rise to the significant reduction of torque ripples including spatial torque harmonics, which have been obtained with FEM.

• Journal of Advanced Marine Engineering and Technology
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• 제6권1호
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• pp.25-33
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• 1982

The characteristics of the stator current and torque of a small three- phase squirrel cage induction motor and studied experimentally under the situation of a single-phase operation due to various causes. Through the experiments, the torque-slip and current-slip curve of single-phase circuit as well as three-phase circuit are obtained and the needed constants are determined. The stator current and torque are calculated by the current and torque equations derived by the unbalanced circuit theory. The numerical values obtained from the above methods are compared with the experimental values under the same conditions. The results of the study are summerized as follow; 1) The values computed by the unbalanced circuit theory generally come to approach the values recorded through experiments. 2) Near the rated load, speed drop is less than 1.2 per cent of the speed of three-phase induction motor and torque reduces less than 3 per cent of it of three-phase induction motor when three-phase induction motor is run under a single-phase. On the other hand, the stator current in a single-phase circuit is more than 1.9 times of it in three-phase circuit. 3) The stalling torque in a single-phase circuit is reduced to about 41 per cent of it in three-phase circuit while the corresponding slip is moved toward the synchroneous speed and the corresponding stator current is increased.

• 전기학회논문지
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• 제58권3호
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• pp.509-515
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• 2009

When a squirrel cage induction motor is loaded, the magnetic noise can increase depending on the load current. It is due to the variation of air gap harmonic fluxes from the rotor current induced by loading. This unfavorable noise can be anticipated by analysing the radial force waves in the air gap, the mode shapes of them, and stator core natural frequencies at each mode. With the experimental tests with the different rotor slot numbers, the variation of magnetic noise depending on the load current is studied and the method to reduce the magnetic noise is suggested with the newly developed magnetic noise analysis program.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.886-887
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• 2011

본 논문에서는 농형 유도전동기의 회전자 도체 형상을 변화시켜 토크 특성을 살펴본다. 회전자의 변화에 의한 영향만을 고려하기 위해 고정자룰 간단히 모델링 하고 전압일정조건을 인가했으며 그에 해당하는 토크 식을 유도했다. 회전자 도체는 가장 기본적인 Canned 형상으로부터 시작하여 복잡한 슬롯 형상까지 도입하여 해석하였다. 해석된 결과들을 이용해 각 도체 형상에 의한 자계 분포와 함께 고찰한다.