• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2237_2238
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• 2009

This paper describes the design process of three-phase squirrel cage induction moter. stator and rotor were modelled with the result obtained from loading distribution on the provided specification. For proving validity of the result obtained from loading distribution, through Maxwell simulator the first test target values, output and efficency, synchronous speed and etc, were compared with the design result.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.805-807
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• 2002

In this paper, a method for an accurate and fast transient analysis, which employs a single slot model for the rotor, is presented. The equivalent circuit parameters are extracted from a combined method of F. E. M and equivalent circuit on 1 slot rotor boundary condition. Two kinds of circuit parameters for each slip are applied to equivalent circuit controlled by variable-voltage variable- frequency. One is the constant parameters at rated speed, and the other is the parameters varying in accordance with slip-frequency. The computer characteristics of the suggested method for four-pole 1.5KW induction motor are compared with those of Equivalent circuit for the transient analysis.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.106-113
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• 2014

Rotor eccentricity is one of the major factors that directly influence the security of horizontal electrical machines, and the critical speed of the shaft has a close relationship with vibration. This paper deals with the influence of thermal expansion on the rotor eccentricity and critical speed in large dry submersible motors. The dynamic eccentricity (where the rotor is still turning around the stator bore centre but not its own centre) and critical speed of a three-phase squirrel-cage submersible induction motor are calculated via hybrid analytical/finite element method. Then the influence of thermal expansion is investigated by simulation. It is predicted from the study that the thermal expansion of the rotor and stator gives rise to a significant air-gap length decrement and an inconspicuous slower critical speed. The results show that the thermal expansion should be considered as an impact factor when designing the air gap length.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.179-186
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• 1998

Three phase squirrel cage induction motor is generally adopted as a traction motor to drive high speed trains because of its robustness for surrounding environment and easy maintenance. In the design of traction molar, reduction of weight is very important in order to reduce kinetic energy to accelerate the vehicle. Therefore, in this paper, design variables of a preliminary designed traction motor to minimize its weight is determined using the optimization technique. Before the optimization process, rotor slot number is determined to reduce vibration and noise by the analysis of magnetic force. As a result, a design example to reduce weight by 12% than that of the preliminary designed motor is presented.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.779-780
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• 2006

This paper describes the effects of rotor-bar broken in induction machines. The analysis has been made on 7.5kW, 4P, 1,768[rpm], three-phase induction motors in a healthy and broken-rotor bars fault conditions at rated loading conditions. The effects of the rotor-bar broken, magnetic force are investigated by finite element method (FEM) and experiment. The results can be useful for real-time on-line monitoring of an induction motor.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.891-895
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• 2004

This paper suggests the techniques in determining the values of the steady-state equivalent circuit parameters of a three-phase squirrel-cage induction machine using immune algorithm. The parameter estimation procedure is based on the steady state phase current versus slip and input power versus slip characteristics. The proposed estimation algorithm is of a nonlinear kind based on clonal selection in immune algorithm. The machine parameters are obtained as the solution of a minimization of least-squares cost function by immune algorithm. Simulation shows better results than the conventional approaches.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2004.10a
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• pp.21-25
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• 2004

This paper suggests the techniques in determining the values of the steady-state equivalent circuit parameters of a three-phase squirrel-cage induction machine using immune algorithm. The parameter estimation procedure is based on the steady state phase current versus slip and input power versus slip characteristics. The proposed estimation algorithm is of a nonlinear kind based on clonal selection in immune algorithm. The machine parameters are obtained as the solution of a minimization of least-squares cost function by immune algorithm. Simulation shows better results than the conventional approaches.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1558-1565
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• 2015

In this paper, we propose a new method for detecting bearing faults using vibration signals. The proposed method is based on support vector machines (SVMs), which treat the harmonics of fault-related frequencies from vibration signals as fault indices. Using SVMs, the cross-validations are used for a training process, and a two-stage classification process is used for detecting bearing faults and their status. The proposed approach is applied to outer-race bearing fault detection in three-phase squirrel-cage induction motors. The experimental results show that the proposed method can effectively identify the bearing faults and their status, hence improving the accuracy of fault diagnosis.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1482-1484
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• 1996

To apply Magnetic wedges to the motor, comparing with not applying, showes its performance change of efficiency increse, reduction of temperature rise, harmonics, and magnetic noise. The motor specification and test condition are 37kW-4P-380V-60Hz,squirrel-cage, three phase induction motor with semiclosed type slots. The result of load test to compare with nonmagnetic wedges showed 1.5% increment of efficiency at 100% load and $8.0^{\circ}C$ decrement of temperature rise at stator coil. And for developing the magnetic wedge matrial, its manufacturing process was setting and TG-DTA, optical microscope, SEM, bending strength and permeability were investigated into the material made of through the process.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1989.10a
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• pp.51-58
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• 1989

In this paper, the technique of particular harmonics elimination in three-phase PWM Inver-ter output waveform and the method for speed control of a squirrel cage I.M. are introduces. The required switching patterns are determind on personal computer and the results are stored in look-up table in EPROM for controlling the switching of the Inverter devices. In this system, the microprocessor(Intel 8086)computes the actual Motor speed from the pulses generated in a Incremental Encoder, compares the actual speed with the reference speed. And the PI(Proportional-Integral) controller is used to adjust the frequency of the Inverter that feeds the Motor.