• 전기의세계
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• v.16 no.1
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• pp.1-2
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• 1967

The development of the frequency converter using semiconductor enables to easily control the speed of alternating current machineries. In such case, it is desired to observe how several characteristics are changed, such as primary current, power factor, torque, secondary output, efficiency and transient performance. In this paper, the above characteristics are investigated by means of computational method from various constants relating to the motor which is designed in rated frequency 60 cycles. Transient fluctuations in motor speed are also observed with graphical method. These have been validated by the experimental results. When the frequency is to be varied in order to control the speed, it is seen that some of characteristics are getting better and others worse contrarily. The above characteristics may be applied to the optimum electrical, mechanical design of the motor which puts emphases on speed control.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.8
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• pp.408-416
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• 1999

The characteristics of permanent magnet synchronous motor are defined by airgap flux and circuit parameters. Interior Permanent Magnet Synchronous Motor(IPMSM) has a nonlinear characteristics due to structural speciality of rotor, so it is difficult to analyze circuit parameters and field-weakening characteristics of IPMSM. This paper presents the calculation of circuit parameters by using Finite Element Method(FEM) taken into consideration of nonlinear characteristics. Using the circuit parameters by FEM, IPMSM is analyzed to field-weakening characteristics and is compared with the Equivalent Magnetic Circuit(EMC) in which lumped parameter is consideration.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.682-684
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• 2015

A 12/14 bearingless switched reluctance motor (BLSRM) with hybrid stator poles has been proposed due to the outstanding decoupling characteristics between the torque and suspending force. However, the motor is a two-phase motor. The output torque of the motor has torque dead zone and high torque ripple. Hence, the motor cannot self-start at some rotor positions. To solve the self-starting problems and reduce the torque ripple, a stepped rotor is proposed in this paper. Then, the motor with the stepped rotor is optimally designed. In the new designed motor, the majority parameters are kept the same with those of original motor; only the torque pole arc and rotor pole shape are optimally designed. The characteristics of the redesigned motor, such as inductance, torque and suspending force, are analyzed and compared with those in the original motor. Finally, the effectiveness of the proposed method is verified by the simulation results.

• Journal of Magnetics
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• v.21 no.3
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• pp.413-420
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• 2016

The permanent magnet synchronous motor has high efficiency driving performance and high power density output characteristics compared with other motors. In addition, it has good regenerative operation characteristics during braking and deceleration driving condition. For this reason, permanent magnet synchronous motor is generally applied as a power train motor for electrical vehicle. In permanent magnet synchronous motor, the most probable causes of fault are demagnetization of rotor's permanent magnet and short of stator winding turn. Therefore, the demagnetization fault of permanent magnet and turn fault of stator winding should be detected quickly to reduce the risk of accident and to prevent the progress of breakdown of power train system. In this paper, the fault diagnosis method using high frequency low voltage injection was suggested to diagnose the demagnetization fault of rotor permanent magnet and the turn fault of stator winding. The proposed fault diagnosis method can be used to check the faults of permanent magnet synchronous motor during system check-up process at vehicle starting and idling stop mode. The feasibility and usefulness of the proposed method were verified by the finite element analysis.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.1914-1920
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• 2014

In this paper, characteristics of blushless direct current (BLDC) motor including core loss are analyzed considering pulse width modulation (PWM) of inverter. Input voltage of BLDC motor due to PWM is calculated considering duty ratio and carrier frequency of inverter in order to control torque or speed of BLDC motor. For the calculation of core loss, the input current with harmonics due to PWM voltage is calculated by using equivalent circuit model of BLDC motor according to switching pattern and carrier frequency. Next, core loss is analyzed by inputting the currents as a source of BLDC motor for FEM. Characteristics including core loss are compared with ones without PWM waveform according to reference speed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.70-76
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• 2007

The purpose of this study is to analyze the characteristics of a domestic developed hydraulic axial piston motor. An experimental apparatus was constructed and the output torque, the input oil pressure, the input flow rate, the speed of motor and oil temperature were measured. They were measured under both no load and load conditions. The results are as follows; 1. Motion of motor became steady state conditions after 5 seconds. 2. Output torque of motor was proportional to input oil pressure under both load and unload. 3. Speed of motor decreased with increasing load. 4. Oil temperature was almost constant. The results of this study will offer the basic data in designing and operating hydraulic axial piston motors.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.722-732
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• 2018

Dual type Independent multi-phase BLDC Motor (DI-BLDCM) is designed to be robust to faulty conditions of motor and drive system. Despite the efforts of the motor design, open-switch faults of DI-BLDCM drive system cause the torque ripple of the motor. This torque ripple makes unwanted sound noise and mechanical vibration of associated systems. This paper proposes four methods for compensating the torque ripple and compares the characteristics of each proposed method. All proposed methods are able to reduce the torque ripple to similar level of the healthy condition, although the motor operates in open-switch fault conditions. However, these methods have different characteristics in various fault conditions. Therefore, from the results of the comparison, the suitable method is selected for the various fault conditions. The feasibility of the proposed methods is proved by the several experimental results.

• 전기의세계
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• v.17 no.4
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• pp.7-12
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• 1968

In recent years the development of the SCR has made possible the control of the power system. It is one example that the speed control of the induction motor can be done by changing the frequency with the S.C.R. This paper is devoted primarily to a study of the running characteristics of the single phase induction motor through the experimental and theoretical methods when the speed of the motor is controlled by varying the conduction period in current with S.C.R. under the constant frequency. We conclude from the experiments that the adjustment of the phase angle in current is equivalent to the change of the supply voltage to the motor. Therefore, the speed control of the motor such as a fan duty motor is possibly by this methods.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.5
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• pp.320-326
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• 2000

The canned motor of 3-phase induction is used for main coolant pump(MCP). The type of motor is canned-motor that stator and rotor are welded by sealed can. So, cooling water flows in the air gap of the canned motor as an independent cycling cooling system from the air gap to yoke of the motor to prevent high temperature of stator can and to lubricate bearing. Heat exchange is occurred between cooling water in the air gap and cooling water from the exterior pump to prevent rising of temperature in the motor. I has to analyze the characteristics of can exactly because the loss and the heat in the can are very important to design MCP. Therefore, thermal analysis is studied considering the effect of eddy-current los induced in the can.

• Journal of Advanced Marine Engineering and Technology
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• v.8 no.1
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• pp.72-84
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• 1984

In this paper, the characteristics relating to the stator voltage control of a small three phase squirrel cage induction motor by means of symmetrically trggered triacs instead of antiparallel SCR's is described. A complete model of the system with 220V, $3{\phi}$, 1HP motor and triac gate control circuit has been designed and tested in the laboratory, and the experimental results are compared with the numerical values. As a result of the above investigation, it is found that the range of induction motor speed control by stator voltage control is narrow.