11-01-2016, 03:50 PM
ABSTRACT
This paper presentation explores the working principle of eddy current brake mechanism, which can be analyzed by Maxwell 3D Transient solver. An eddy current brake, like a conventional friction brake, is responsible for slowing an object, such as a train or a roller coaster etc. Unlike the friction brakes, which apply pressure on two separate objects, eddy current brakes slow an object by creating eddy currents through electromagnetic induction which create resistance, and in turn either heat or electricity. In this paper, linear Halfback magnetized mover is applied to eddy current braking system for high speed. For such a breaker, we give analytical formulas considering end effects for its magnetic field, eddy current distribution, forces according to the secondary relative permeability, and conductivity. The results given here are purely analytic & applicable.
INTRODUCTION
The term “EDDY”
Focault Bae J. S.(2004) found that when magnetic flux linked with a metallic conductor changes, induced currents are set up in the conductor in the form of closed loops.
These currents look like eddies or whirl pools and likewise are known as eddy currents. They are also known as Focault’s Current.
When a time-varying magnetic flux passes through a conductive material, eddy currents are generated in the conductor. These eddy currents circulate inside the conductor generating a magnetic field of opposite polarity as the applied magnetic field. Bae J. S.(2004) The interaction of the two magnetic fields causes a force that resists the change in magnetic flux. However, due to the internal resistance of the conductive material, the eddy currents will be dissipated into heat and the force will die out. As the eddy currents are dissipated, energy is removed from the system, thus producing a damping effect. There are several different methods of inducing a time-varying magnetic field, and from each method arises the potential for a different type of damping system. Therefore, the research into eddy current and magnetic damping mechanisms has led to a diverse range of dampers. The majority of the eddy current damping has taken place in the area of magnetic braking that has received significant interest is the use of eddy current dampers for the suppression of structural vibrations. However, much of this research is not concentrated in one area, but has been applied to a variety of different structural systems in a number of distinct ways.