• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.644-646
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• 2000

An induction motor can be controlled like a separately excited do motor by field oriented control(or vector control). In vector control, Because the transformation of the stator's 3-phase current into two orthogonal current is required. the control scheme is complicated. But, Yamamura proposed a field acceleration method(FAM) without the phase transformation. FAM simplify an implementation control scheme for induction motors. In this paper, the analysis of transient phenomena of a squirrel-cage induction motor was achieved by the spiral vector method and the phase segregation method. It simplified control schemes more than those of vector control.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.702-704
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• 2000

Designing of the squirrel cage AC Traction Motor has many difficulties which has to be small shape in order to be suitable into bogie frame, high efficiency and light weight. It means that induction motor for tractive efforts has to be different magnetic and electric loading ratio from industrial induction motor. This paper is devoted to an examination of how this ratio affects overall design concept and. hence the main design points for traction motor. Also studied is the changed coefficients of the magnetic and electric loading ratio squirrel cage induction motor for the traction purpose, which has been already identified from the referance book for industrial purpose induction motor.

• Smart Structures and Systems
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• v.9 no.4
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• pp.303-311
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• 2012

The possibility of suppressing critical speeds by using electromagnetic actuators (EMAs) is assessed experimentally in this paper. The system studied is composed of a horizontal flexible shaft supported by two ball bearings at one end and one roller bearing that is located in a squirrel cage at the other end. Four identical EMAs supplied with constant current are utilized. The EMAs associated to the squirrel cage constitutes the hybrid bearing. Results obtained, show that the constant current, when applied to the EMAs, produces a shift of the first critical speed toward lower values. Moreover, the application of constant current for a speed interval around the critical speed enables a smooth run-up or run-down without crossing any resonance.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.154-158
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• 2013

Reduction of electromagnetic vibration and acoustic noise from three-phase squirrel-cage induction motors (IMs) is very important, particularly from the standpoint of environmental considerations. Although the electromagnetic vibration of IMs has been studied for several years, the relationships between the radial distribution of the electromagnetic vibration and noise and the electromagnetic forces responsible for them have not yet been analyzed in sufficient detail. In the present study, we investigated this relationship experimentally for a small IM under different load conditions. Our results clearly show that the radial distributions of the dominant electromagnetic vibration and noise components match the mode shape of the dominant electromagnetic force producing these components.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.12
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• pp.704-713
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• 2002

This paper describes operational characteristics of wind turbine induction generators interconnected with distribution networks using PSCAD/EMTDC. Due to the simple and durable structure, induction generators are the most common type used in wind Power generation. Generally, induction generators are classified into two groups according to the shape of rotor, one is squirrel-cage type and the other is wound-rotor type. In this study, we simulate the start-up and the output variation of generators interconnected with distribution networks and compare the operational characteristics of squirrel -cage type and wound-rotor type induction generators located in the unfaulted distribution lines about the disturbance occurred on the associated distribution feeders emanated from the substation to which wind turbine generator is connected. In order to obtain the realistic results, we use the radial distribution network of IEEE 13-bus model.

• Proceedings of the KIEE Conference
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• summer
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• pp.896-898
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• 2004

The lagging reactive power should be supplied for the excitation of isolated squirrel-cage induction generators by external circuit. This paper deals with a technique to drive the equations for analysis of the excitation characteristics and performance of an isolated squirrel-cage induction generator from the conventional equivalent circuit of induction machine, transform the equations into d-q coordinates to use vector control technique, and carry out the simulation of an induction generator system with various conditions using MATLAB. The results of the simulation indicate that moderate reactive power can be controlled effectively to maintain constant voltage over a wide range of the rotor speeds and loads.

• Journal of Power Electronics
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• v.6 no.3
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• pp.245-252
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• 2006

This paper presents a method based on neural networks to detect the broken rotor bars and end rings of squirrel cage induction motors. At first, detection methods are studied, and then traditional methods of fault detection and dynamic models of induction motors by using winding function model are introduced. In this method, all of the stator slots and rotor bars are considered, thus the performance of the motor in healthy situations or breakage in each part can be checked. The frequency spectrum of current signals is derived by using Fourier transformation and is analyzed in different conditions. In continuation, an analytical discussion and a simple algorithm are presented to detect the fault. This algorithm is based on neural networks. The neural network has been trained by using information of a 1.1 KW induction motor. This system has been tested with a different amount of load torque, and it is capable of working on-line and of recognizing all normal and ill conditions.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.48-50
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• 2008

A wind power system with squirrel-cage induction generator has irregular change of output power according to the sudden change of wind speed. This paper describes the development of a active and reactive power compensator, which is composed of a 3-phase inverter and a bidirectional DC/DC converter with super-capacitor. The operational characteristic was analyzed through simulations with PSCAD/EMTDC and experimental works with a scaled model. The developed system can continuously compensate the active power change with energy storage and the reactive power change with 3-phase inverter.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.2
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• pp.62-66
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• 2015

Induction generator is easy to durability and maintenance than the synchronous generator. So, recently Induction generator has been widely applied to small-scale hydroelectric power plant. When the rotor is operating faster than synchronous speed, induction machine can generate electric power. Induction generator has a large inrush currents, such as the starting current of the induction motor. Induction motor has been designed a variety of rotor shape in order to reduce starting current. Since the occurrence of high inrush current cause a voltage drop to the system, it will need to reduce possible. Because the starting current of the squirrel-cage induction motor varies in accordance with the rotor shape, it is necessary to analyze the magnitude of inrush current in order to apply to the generator. In this study, we analyzed the inrush current and the voltage drop caused in accordance with the rotor shape of 1500kw induction generator.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1057-1058
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• 2007

This paper proposes an alternative vibration detection method in a squirrel-cage induction motor using flux sensors. The air-gap flux will be changed when mechanical vibration occurs by bearing fault as well as broken rotor bar and air-gap eccentricity. For detecting those flux variations due to vibration, search coils are installed at stator slots. The induction motor with 380 [V], 7.5 [kW], 4 [Poles], 1,760 [rpm] ratings is used. Magnitudes and distortion of the induced voltage from flux sensors are used to discriminate faulted types. As a result, the flux sensor has been proven to be useful for vibration detection. It is compared to the result with vibration sensor as well.