• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.101-109
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• 2008

Induction motor needs reactive power to sustain the electromagnetic field required for rotating. If reactive power is provided by the load side instead of the source side, power factor will be increased. Power factor of induction motor is usually low and needs to be compensated with power capacitor. In domestic regulations, Capacitor capacity for the power factor correction of induction motor should be complied with the recommended value by the motor output. But, at the same output, characteristics of induction motor is different from each other by the rotation speed and is not suitable for application of regular capacitor value regardless of motor's characteristics. In this paper, we compared to each other with the existing value and new proposed value with rotation speed under the same output condition, confirmed that power capacitor capacity is needed to upgrade for the better power factor.

• 전기의세계
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• v.25 no.4
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• pp.68-72
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• 1976

This study is initiated to solve the problem that the development of an electric machine to drive heavy horse-power load required in the rural district, where only single phase supply is available, is very urgent. As a method for this purpose, the single/three phase converter by single phase induction machine with a tapped auxiliary winding, running unloaded mechanically under single-phase source and supplying three-phase output to a loaded 3-phase induction motor, is devised and the pilot machine is put into test. Analysis based on hybrid equivalent circuit for the phase converter and symmertical component theory for the 3-phase load motor and practical experiment result in that optimum auxiliary winding ratio is to be 1.25 rather than theoretical .root.3/2 in order to keep the voltage unbalance ratio of 3-phase output from the converter as low as possible in both cases of starting and running the load motor.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.660-662
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• 2001

This paper describes the problems generated with the use of PWM ASDs with induction motors. The major effect of harmonic voltages and currents in induction motors is increased the heating due to iron and copper losses at harmonic frequencies. The harmonic components thus affect the motor efficiency and developed the torque. In order to investigate the effect of harmonics which is caused by using of nonlinear load at the low voltage system, we set up simple load system and measured the voltage and current. Measurement results show that additional operation of induction motor at the parallel bus in using nonlinear load such as ASD is helpful to the reduction of harmonic current.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.169-175
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• 2006

This paper describes how an Artificial Neural Network(ANN) can be employed to improve a speed estimation in a vector controlled induction motor drive. The system uses the ANN to estimate changes in the motor resistance, which enable the sensorless speed control method to work more accurately. Flux Observer is used for speed estimation in this system. Obviously the accuracy of the speed control of motor is dependent upon how well the parameters of the induction machine are known. These parameters vary with the operating conditions of the motor; both stator resistance(Rs) and rotor resistance(Rr) change with temperature, while the stator leakage inductance varies with load. This paper proposes a parameter compensation technique using artificial neural network for accurate speed estimation of induction motor and simulation results confirm the validity of the proposed scheme.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.603-605
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• 1994

The Single-Phase induction motor is widely used in home appliances, especially refrigerator, air conditioner and washing machine. Recently many home appliances that use the motor require the speed control to get the various and convenient functions for the customers. Generally it is so hard to control the speed of the Single-Phase induction motor and to get the wide range of the speed variation. In this raper, the speed controller using P-I is designed for the Single-Phase induct ion Motor. The experimental results of the phase controller using P-I show the wide speed control of the Single-Phase induction motor and rebuff control to load change.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.47-48
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• 2005

This paper describes how an Artificial Neural Network(ANN) can be employed to improve a speed estimation in a vector controlled induction motor drive. The system uses the ANN to estimate changes in the motor resistance, which enable the sensorless speed control method to work more accurately. Flux Observer is used for speed estimation in this system. Obviously the accuracy of the speed control of motor is dependent upon how well the parameters of the induction machine are known. These parameters vary with the operating conditions of the motor; both stator resistance(Rs) and rotor resistance(Rr) change with temperature, while the stator leakage inductance varies with load. This paper proposes a parameter compensation technique using artificial neural network for accurate speed estimation of induction motor and simulation results confirm the validity of the proposed scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.6
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• pp.635-640
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• 2014

Detection and diagnosis of incipient bearing fault in an induction motor is important for the prevention of serious motor failure. This paper presents an analysis of the effect of a faulty bearing on the stator current of an induction motor. A bearing fault leads to torque oscillations which result in phase modulation of the stator current. Since the torque oscillations cause specific frequency components at the stator current spectrum to rise sharply, the bearing fault can be detected by checking out the faultrelated frequency. In this paper, a mathematical model of the load torque oscillation caused by a bearing fault is presented. The proposed model can be used to analyze the physical phenomenon of a bearing fault in an induction motor. In order to represent the bearing fault effect, the proposed model is combined with an existing model of vector-controlled induction motors. A set of simulation results demonstrate the effectiveness of the proposed model and represent that bearing fault detection using a stator current is useful for vector-controlled induction motors.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.37-46
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• 1995

Along with the recent trend of complexity and long distance transmission in power system, dynamic analysis of stability considering the load characteristics is an important subject. In this paper, the influence of the induction motor loads on the power system voltage is investigated. The influence of the inductive load ratio and the inertia of induction motor on the voltage response of the power system are examined, and in the case of the high percentage of the induction motor load, induction motors in the power system can lead to transient voltage instability even under the system condition such as switching operation. The application of static condenser(SC) to prevent the transient voltage instability is introduced.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1088-1090
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• 2002

This paper described a robust control of an induction motor using a disturbance cancellation observer of a feedforward control. The speed response of conventional PI controller characteristic is affected by variations of load torque disturbance. In the proposed system. the speed control characteristic using a feedforward control isn't affected by a load torque disturbance.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.137-139
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• 1991

This paper proposes a minimum power factor control for maximum efficiency operation of an induction motor, under low load condition. Minimum input or maximum efficiency operation is achived by properly adjusting the amplitude of the stator voltage, with the three phase AC voltage controller. Through the simulation, the relationships between the delay angle and input power under various load conditions are examined. Experimental results are also given, which show good coincidence with the simulation results.