Hyun-June Park

Influence of the Construction of Secondary Reaction Plate on the Transverse Edge Effect in Linear Induction Motor

In this paper, linear induction motor is analyzed by 3-D finite-element method (3-D FEM) to consider influence of construction of secondary reaction plate on the transverse edge effect. A effective 3-D analysis model for considering the transverse edge effect caused by the finite widths of the primary and the secondary is not only proposed, but also the simple method measuring the transverse edge effect by using the patterns of currents induced in the secondary reaction plate is proposed. With this effective analysis method, various models with overhang and cap have been analyzed to consider the relationship between the construction of secondary reaction plate and the transverse edge effect.

Exit end effect reduction of a linear induction motor for the deep-underground GTX

The end effect of a linear induction motor has been well known for several decades, especially for high speed operation. Nevertheless, exit part of the primary is not dealt with relatively compared with the entry part because of its minor effect. However, exit part is one of keys to weaken the dolphin phenomenon which occurs in the high speed operation. In this paper, concept of the virtual primary core is introduced and chamfering of the outlet teeth is proposed to minimize the longitudinal end effect at the exit zone. For this, LIM for the high-speed deep-underground GTX is designed and analyzed by using finite element method. From the results, it is confirmed that the chamfering is effective without losing thrust force.

Air-gap control system of a linear induction motor for a railway transit

In order to realize a traction system with high efficiency and performance for a railway transit, many researchers have continued to study on a linear induction motor (LIM). However, most of researches are limited in LIM unit design. On a moving LIM, the change of an air-gap (it occurs by a construction tolerance of a secondary reaction plate) can lead to decrease a smoother ride and efficiency of the railway transit system. Therefore, a uniform air-gap operation of the LIM is important issue to improve the system efficiency. However, the researches about the air-gap length control of the LIM have been not advanced a lot due to a technical and high-cost problem. Therefore, in this research, the authors introduce an air-gap control system to control the air-gap length which depends on the flatness of the secondary reaction plate when the LIM is been operating. Then, through a dynamic modeling and analysis of the system, the authors analyze characteristic variations of some parameters (spring coefficient, damping coefficient, displacement, and exiting force) which compose the system, and conduct a research on feasibility of the system.

Implementation of Optical-based Measuring Instrument for Contact Wire Geometry in Electric Railway

We propose an optical-based measuring instrument of catenary system in electric railway. This system was made to utilize line scan camera as inspecting system to measure the stagger and height of overhead contact wire in railway and composed with optical type source and FPGA-based image acquisition system with PCI slot. Vision acquisition software has been used for the application to programming interface for image acquisition, display, and storage with a frequency of sampling. To check the validity of our approach for the intended application, we monitored height and stagger in the overhead wire of a high-speed catenary system in Korea. The proposed optical-based measuring instrument to measure the contact wire geometry such as the hight and stagger shows promising on-field applications for online condition motoring. We expect that a new generation of real-time instruments with demanding various conditions motoring requirement in railway can be easily integrated into optical-based measuring instrument system.

Influence of flatness of the secondary reaction plate on performance of a linear induction motor

This paper presents the influence of flatness of the secondary reaction plate on performance of a linear induction motor. Construction tolerance of the plate affects directly to the cost and performance of the Linear metro. Detailed simulation of the flatness has been done by using FEM.