• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.475-480
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• 2006

In this paper, a new approach for detecting broken rotor bars in a squirrel-cage induction motor is proposed. The air-gap flux variation analysis was done using search coils inserted in stator slots when broken rotor bar occurs. An accurate modeling and analysis of air-gap flux variation in the induction motor are developed using finite-element (FE) software packages, and measurement of the flux are made using search coils. The simulation was done for the induction motor with 380 [V], 5 [HP], 4 Poles, 1,742 [rpm] ratings using the commercial FE analysis tool. The simulation and experiment results can be useful for detecting the broken rotor bar of an induction motor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.370-376
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• 2005

The single-phase induction motor is simple and durable, but the efficiency is low. Therefore, electric motors like HLDC and LSPM(line-start permanent magnet motor) that use the permanent magnet have been studied. The most advantages of single-phase LSPM is having the same stator as the stator of the single-phase induction motor and permanent magnets are just inserted in the squirrel cage rotor of the single-phase induction motor. But the characteristics of single-phase LSPM synchronous motor has very complex characteristics until the synchronization and if the design is not suitable, the single-phase LSPM synchronous motor cannot be synchronized. We designed a single-phase LSPM using the same stator and winding as the conventional single-phase induction motor, but newly designed the permanent magnets considering air gap magnetic flux density. The transient characteristics of the single-phase LSPM is not good because of a magnetic breaking torque, however, it can be improved by redesigning the rotor bars. We are proposed the design method of rotor bar for the single-phase LSPM to start softly and to make synchronization easily.

• 대한전기학회논문지
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• 제40권6호
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• pp.567-573
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• 1991

Full direct digital control of induction motor driver is implemented with a minimal hardware structure. This paper deals with the presentation of a low-cost single-chip microprocessor-based control system for three-phase PWM generation and vector control that control speed of the induction motor using the field-oriented control method. Rotor flux is estimated using the indirect sensing method based on the rotor circuit equation in the synchronously rotation reference frame, and slip angle and rotor position are calculated from rotor angular velocity and stator current. Through simulation and experiment, it is shown that the proposed scheme gives good static and dynamic performance to the induction motor drive.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.379-384
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• 2007

In this paper, a new method for detecting rotor vibrations in a squirrel-cage induction motor is proposed. The air-gap flux variation analysis was done using search coils inserted in stator slots when rotor vibration conditions occurs. An accurate modelling and analysis of air-gap flux variation in the induction motor are developed using finite-element (FE) software packages, and treasuring the flux are made using search coils. In the FE analysis and experiment, the three-phase squirrel-gage induction motor with 380 [V], 7.5 [kW], 4 Poles, 1,768 [rpm] ratings is used. The simulation and experiment results can be useful for detecting rotor vibration of the induction motors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.827-828
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• 2006

This paper proposes a new method for detecting broken rotor bars in a squirrel-cage induction motor. The air-gap flux variation analysis was done using search coils inserted in stator slots when broken rotor bar occurs. An accurate modeling and analysis of air-gap flux variation in the induction motor are developed using finite-element(FE) software packages, and measurement of the flux are made using search coils. The simulation was done for the induction motor with 380 [V]. 7.5 [kW], 4 Poles, 1,760 [rpm] ratings using the commercial FE analysis tool. The simulation and experiment results can be useful for detecting the broken rotor bar of an induction motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.933-935
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• 2003

The single-phase line start permanent magnet motor(LSPM) have a rotor cage bar for induction starting and permanent magnets, providing synchronous torque. So, LSPM is vary complex and difficult to analysis transient characteristics and rotor design. In this paper, F.E.M analysis about single-phase line start permanent magnet motor and compare of the single-phase line start permanent magnet synchronous motor's transient characteristics by size and position of rotor bar.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.802-808
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• 2000

This paper characterizes the electromechanical parameters due to the fault of rotor bars in a squirrel cage induction motor. Simulation is performed to investigate how broken rotor bars have effect on them by solving the time-stepping finite element equation coupled with magnetic field equation, circuit equation and mechanical equation of motion. It shows that the asymmetry of magnetic flux due to the broken rotor bar introduces the beating phenomenon in time domain and the sideband frequencies in frequency spectra, respectively, to the stator current, torque, speed, magnetic force and vibration of a rotor. However, vibration of a rotor would be the most effective monitoring parameters to detect the faults of rotor bars.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.709-712
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• 2003

Recently, high noise problem was experienced during the development of 2-pole squirrel cage motor for industrial compressor. In order to firstly identify the noise characteristics, a variety of measurements were carried out. It was found out that high noise was dominated by linear and nonlinear slot noise components. For the development of low noise indusrial motor, the air gap between rotor and stator in the motor was firstly enlarged. Secondly, it was also modified for the cooling housing to have high absorption features. Consequencely, low noise 2-pole motor having the noise level of less 80㏈(A) was developed. In this paper, a series of noise identification and control process for this motor are introduced.

• 대한전기학회논문지
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• 제41권9호
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• pp.1003-1012
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• 1992

This paper presents and analysis method for designing a squirrel cage induction motor, which is aimed at analyzing the dynamic characteristics of magnetic field. This scheme is capable of estimating the effects of slot harmonics due to the rotation of rotor by utilizing Macro-airgap element combination, Voltage source treatment and Time difference algorithm. Furthermore, this strategy presents and approach which effectively compensates for end-ring of rotor. And direct convergence method is applied for considering a magnetic nonlinearity in core. In addition to the precision and the convergence study of algorithm, comparisons with experimental values prove the accuracy of this analysis method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.41-43
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• 1997

This paper represents the comparison of harmonic loss characteristics of the inverter-driven 3-phase squirrel cage induction motor with slit and U-iron bridge slots of rotor. Two-dimensional time-stepped finite element method is used for electromagenetic field analysis. And spectrums of bar current, phase current, and torque are compared in each case.