• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.415-417
• /
• 1989

In this paper we introduce electrical and mechanical properties of PPLP, an insulation system of Cellulose/Extruded Polypropylene/Cellulose Paper, and characteristics of 345KV O.F cable employing the PPLP. This cable shows dielectric loss less than 50% and has excellent impulse breakdown strength higher than 17%, respectively, compared with those of the conventional cables. Accordingly, a more compact cable with reduced thickness of the insulation layer, which has remarkable profits in economics, has been developed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.12
• /
• pp.1128-1133
• /
• 2006

The most important thing to secure safety and reliability of railway vehicles is to verify performance characteristics of equipments, and related companies or research institutes had many efforts to verify performances and functions of equipments synthetically and efficiently. KHST(Korean High Speed Train) has been developed by KRRI (Korea Railroad Research Institute). An electric railway system is composed of high-tech subsystems, among which main electric equipment such as transformers and converter are critical components determining the performance of rolling stock. We developed a measurement system for on-line test and evaluation of performances of KHST. The measurement system is composed of software part and hardware part. Perfect interface between multi-users is possible. A new method to measure temperature was applied to the ]measurement system. By using the system, fault diagnosis and performance evaluation of electric equipment in Korean High Speed Train was conducted during test running.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.05a
• /
• pp.166-171
• /
• 2001

An electric drill is a handy tool used in a machine shop, which consists of motor, gear, bearing, shaft, and case, i.e., a gear driving system. Low level vibration and noise of the electric drill can bring the assurance of the quality and reliability of the machine. The vibration sources of the electric drill should be investigated for the reduction of the vibration and noise of the system. Through the experiments in a laboratory and the various signal processing procedure for the measured vibration and sound signals, the characteristics of the vibration and noise of the electric drill are investigated. And its propagation path is sought using partial coherence technique.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.50 no.1
• /
• pp.75-82
• /
• 2014

In vibration analysis of ships, the principle aim is to determine the natural frequencies and excitation frequencies, and use this information to avoid resonances and vibration damage. The simplest method is to prevent resonance conditions, which is effective as long as the natural frequencies and excitation frequencies can be regarded as independent from environmental conditions. For ships that use electric propulsion systems, the sources of vibration are reduced compared with those caused by a diesel engine or other combustion-based propulsion systems. However, the frequency spectrum of these vibrations may be different; therefore, to understand the characteristics of the electric propulsion, we also should investigate how the ship responds to these vibrations. We focused on a 1,000-ton deadweight (DWT) ocean-research vessel using an electric propulsion system and analyzed the response to vibration.

• Proceedings of the KWS Conference
• /
• 2009.11a
• /
• pp.235-238
• /
• 2009

To study the relationship between spark ignition and the gap in the nano-scale region, the electric potential was applied to between a Pt-Ir tip and a gold substrate. The tip was sharpened by electro-chemical etching process in the solution of $CaCl_2;H_2O$ and acetone. The radius of tip was measured to be around 200nm and attached to the scanning probe microscope to control the gap between the tip and the substrate. The electric potential of 10V to 80V was applied to initialize the spark. The gaps and the current profile were measured to analyze the characteristics of spark ignition. A spark sustaining time was measured to be between 50ns and 200ns depending on the applied electric potential and the gap between the electrodes. The continuous electric discharge was successfully sustained up to 1 second of spark or arc time. The developed process can be applicable to the micro-scale fabrication of automotive sensors as a similar concept of GTAW.

• Proceedings of the KIEE Conference
• /
• 1998.07e
• /
• pp.1650-1652
• /
• 1998

This paper describes characteristics of electric field waveforms associated with multiple-lightning discharges. The electric field measurment system. consists of hemi-sphere antenna 30 cm in diameter. integrator and data acquisition device. The frequency bandwidth is from 200 Hz to 1.56 MHz, and the sensitivity is 0.96 mV/V/m. The detected electric field signal is digitized every 500 ns with the resolution of 12-bit and the length of 2 kilowords and is registered at a personal computer. Also parameters of the electric fields associated with multiple-lightning discharges are ststistically analyzed.

• Proceedings of the KIEE Conference
• /
• 1996.11a
• /
• pp.32-35
• /
• 1996

This paper analyzes characteristics of PMLSM using 3 dimensional equivalent magnetic circuit network method (3-D EMC). PMLSM of which the effective electric-airgap is not only very large, but also the width is finite width lateral edges has much leakage flux. Therefore, 2-D analysis method cannot consider it so carefully that 3-D analysis method must required. 3-D EMC which will be used for analysis of PMLSM performs modeling of it including solt and teeth structure, uses the magnetic motive force of stator winding and permanent magnet as source. and calculates magnetic flux density and force considering nonlinear characteristics of materials. we verified analysis validity by comparing simulation results with expermental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.49-53
• /
• 2006

In this paper the thermal aging characteristics of transformer fluid were considered. First, the temperature rise characteristic in transformer winding was discussed. The temperatures were rapidly increased immediately with applying load and then the temperature was followed the exponential temperature rise model. Next, Capacitance and leakage current characteristics of the transformer fluid were measured during the over-loading operation. The capacitance of vegetable fluid and leakage current were evidently increased wit aging time. So the simple methods could be applied to diagnosis of the transformer aging

• IEMEK Journal of Embedded Systems and Applications
• /
• v.17 no.2
• /
• pp.85-92
• /
• 2022

Currently, various researches on electric vehicle battery systems have been conducted from the viewpoint of safety and performance for SoC, SoH, etc. However, it is difficult to build a precise electrical model of a battery system based on the chemical reaction and SoC prediction. Experimental measurements and predictions of the battery SoC were usually performed using dynamometers. In this paper, we construct a simulation model of an electric vehicle system using Matlab Simulink, and confirm the response characteristics based on the vehicle test driving profiles. In addition, we show that it is possible to derive the correlation between the SoC, voltage, and current of the battery according to the driving time of the electric vehicle in conjunction with the BMS model.

• Journal of ILASS-Korea
• /
• v.29 no.1
• /
• pp.38-44
• /
• 2024

This study investigates the flow characteristics of propane-air premixed flames on AC electric field using the Schlieren method. A voltage was applied to the ring electrode and the burner was grounded to form an electric field, and the applied voltage was fixed at 16 kV (V_pp). Results show that under the application of AC electric fields, flow around the flame oscillated only at frequencies below 50 Hz, and no oscillation was observed above this frequency range. Flame height oscillated with frequency in the range of 25 to 300 Hz, with frequency doubling observed in the range of 25 to 150 Hz. The flammability limit increased with frequency up to 250 Hz, but in the high-frequency range above 250 Hz, the flammability limit did not increased and converged.