• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2075-2076
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• 2011

The stator winding faults diagnosis technique based on MCSA is as follows. Firstly, collecting the 3 phase motor currents, that signal is transformed by (d-q transform, $i_d$, $i_q$). Park's vector pattern, the circle that is down by d-q transformed currents($i_d$, $i_q$). The circle is widely used for stator winding faults detection. The current distortion ratio(DR), defined by the ratio of max-axis and min-axis of ellipse of Park's vector's pattern. In this study, distortion ratio of Park's vector pattern is suggested for Auto diagnosis of stator winding short fault and usefulness of distortion ratio is verified through simulation using LabVIEW program.

• 전기의세계
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• v.28 no.3
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• pp.65-71
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• 1979

This paper examines the reasonable winding arrangements of designing tapped winding capacitor motors to used in two voltage sources. The approach of this paper is based partly on a hybrid equivalent circuit of a single phase induction motor, together with an experimental method by sample machines. In results, the distribution of etra and main windings ia the stator is to be balanced in each magnetic pole and in order to have the same torque output characteristics for two different voltage sources, the extra/main winding ratio is to be adjusted. Experimental results obtaired with sample macines of about 1/8 hp output rating are used with analysis to predict the favorable winding conditions.

• Proceedings of the KIEE Conference
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• 1983.07a
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• pp.79-82
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• 1983

상변환에 의한 농형유도전동기의 1/3, 2/3 속도제어 방법에 대하여 연구하였고, 종래의 국수변환 방법과 비교하였다. 1마력, 36슬롯을 모델로 하여 1800, 1200, 600rpm을 얻어 내었으며, 국수변환 방법에 비하여 고정자의 크기, 슬롯수, 동량을 줄일 수 있는 장점을 가지고 있었다.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.217-220
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• 2003

In this paper, Inverter drives adopting 2 phase space vector SRP-PWM (Separately Randomized Pulse Position PWM) with fixed switching frequency is proposed. The proposed 2 phase space vector SRP-PWM scheme is based on the 3 phase SRP-PWM. In the proposed SRP-PWM scheme, each of two phase pulses is located randomly in each switching interval. The experimental results show that the voltage and acoustic noise harmonics are spread to a wide band area. Also, the performance of the proposed 2 phase SRP-PWM and the conventional center aligned SVM are compared to each other. In resuit, the speed response is nearly simitar to each other from the viewpoint of the v/f constant control.

• Journal of the Korean Society of Safety
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• v.37 no.4
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• pp.20-27
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• 2022

This article aims to develop an algorithm that detects fire pump defects by analyzing the current signals of an induction motor, which are triggered by changes in the flow rate and pressure of multistage volute pumps that are used for fire services. The operational status of the pumps was categorized into three: first, normal operation; second, a defect that is caused by a change in the current value; and third, a defect occasioned by a change in current, pressure, and flow rate. When a fire pump was in normal operation, the motor's operating current was measured between 5.06 A and 6.9 A, the flow rate was estimated at 0-0.27 m³/min, and the pressure ranged from 0 to 0.47 MPa. In the event that a defect was caused by an abnormal current value in the motor, it was attributed to the pump's adherence. Furthermore, if there was no source of water, the defect was considered to have been induced by phase-loss operation, no-load operation, or run-stop operation, with the current value of each scenario being measured at > 52.8 A, < 4.13 A, > 45.15 A, and < 3.8 A, respectively, placing its overall range between 0 and 50 A. The sources of defects were detected based on an analysis of the flow rate, pressure, and current, which represent the following causes: air inflow into the casing, inadequate suction of water, and reverse-phase operation, respectively. Each cause entailed the following values: when air seeped into the casing, the pressure was measured at 0.24 MPa irrespective of changes in the flow rate; when there was inadequate suction of water, the pressure was recorded between 0 and 0.05 MPa despite changes in the flow rate; and when the power line's reverse-phase loss was the cause of the defect, the pressure was measured at 0.33 MPa for a flow rate of 0 L/min, and a higher flow rate decreased the pressure to nearly 0 MPa. The results of this study will enable engineers to develop a pump defect detection algorithm that is based on an analysis of current, and this algorithm will facilitate the execution of a program that will control a fire pump defect detection system.

• Journal of the Korean Professional Engineers Association
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• v.22 no.4
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• pp.12-16
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• 1989

This paper presents a n analysis of the output voltage waveforms of the double sinusoidal modulated PWM inverter, and are studied on the driving characteristics through the 3 phase induction motor using 6502 microcomputer. The double sinusoidal modulated waves are produced during the interval 4$\pi$/3 [rad] for one cycle, and the switching loss can be reduced. The amplitude of fundamental wave of double sinusoidal modulated PWM inverter is 1.15 times higher than that of the sinusoidal PWM inverter, but the practical measured value by FFT analyzer is 1.13 times.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1887-1891
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• 2008

In this paper, we dealt with a partial discharge (PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage induction motors. The PD measurement system consists of a coupling network, a low noise amplifier, and associated electronics. A shielded box was used to reduce environmental noise. Frequency characteristic of the coupling network was estimated by a sinusoidal signal input, and the low cut-off frequency of the coupling network was 1 MHz (-3 dB). Also, we carried out a calibration test for the PD measurement system. Sensitivity of the system was of 84 m$V_{max}$/pC between stator winding and enclosure. In application test on a low-voltage three phase induction motor (5 HP), we could detect 88 pC at AC 800 $V_{max}$.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2110-2112
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• 1997

The induction motor drive for the spindle of machining center is required to do not only a constant torque operation in low speed region(below base rpm), but also a constant power operation in high speed region(beyond base rpm). Also, control voltage shortage due to high speed operation must be overcome. The vector controlled inverter system with input 3 phase pwm converter is designed for that kind of condition. We experimented the performance of the inverter system with spindle motor made by Hyosung industries co.

• 전기의세계
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• v.28 no.3
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• pp.72-77
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• 1979

The object of this paper is to try to develope Tulular Liner Induction Motor which consists of primary stator that generates traveling magnetic field from the three-phase winding of formed-wound concentric coil, and try to identify the characteristics of starting force. To indentify the theoretical starting force formular we have quoted the conventional Maxwell's basic equation and Poisson's equation which are used in the general machines thereby having obtained the formular of the current with in the conductor and of the air gap magnetic field respectively. General starting force formular is acquired by applying the formular of the current and magnetic field which was theoretically derived above. To this theoretically starting force formula various constants and the values of magnetic flux density resulting from the experimental motor are applied to present theoretically calculated values. Comparing these theoretically caculated values experimentally weighed values, we have proved the validity of theoretical research.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.125-132
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• 2001

This paper proposes integrated safety diagnosis system of motor used in a ship. It carried out the safety diagnosis for insulation-resistor and current. The motor exposed to sea breeze and oil all the time is able to have problems as a over-current, reduction of the insulation-resistor and so on. These problems impact on the safety navigation, and occur a heavy casualties and loss of property. The proposed system is able to sense error of the motor before a accident occur, by verifying and controlling value of the insulation-resistor and current in working area or control room. The validity of the proposed system is verified through experiment results on the 3-Phase induction motor.