A Parametric Analysis of Magnetic Braking - The Eddy Current Brakes - For High Speed and Power Automobiles and Locomotives Using SIMULINK

Abstract

Eddy Current braking technique is a classical example of how effective and efficient braking be obtained from application of magnetic field. Eddy current braking is based on the principle of relative motion between a magnetic source and a metal. In this paper, eddy current braking system is modeled in SIMULINK and effects of various parameters are observed over the overall braking. This would provide a comparative study between the various parameters involved and understand the braking system. I.INTRODUCTIONBraking forms an important part of motion of any automobile or locomotive. Effective braking ensures the safety of the passengers and goods an automobile or a locomotive is carrying. Hence, new and effective braking techniques are required which increase the efficiency of the existing braking system by either replacing the older systems or by providing an auxiliary support whenever required. The main advantage of eddy current brakes lies over the fact that, more the relative motion between the metal and the magnetic source, more would be the braking force observed by the metal disc. Owing to their efficiency at very high speeds these brakes are used in high speed locomotives and their scope can be further increased to high performance/racing automobiles. Another important advantage is that it has no loses due to friction and thus improves the overall efficiency of the system. Thus, it is important to understand the various parameters that affect the braking force. II.BACKGROUNDCurrent is induced when a conductor is introduced in a variable magnetic flux. This can be achieved by either exerting a time varying magnetic field over a static conductor or a static magnetic field over a moving conductor. In Eddy current braking system, a conducting disc is rotated in the air gap of the magnetic field produced by a permanent magnet or an electromagnet. Using electromagnets is a much efficient method since; the setup can be activated as per requirement. When the disc rotates in the magnetic field, eddy currents are induced into the conductor in such a manner that they oppose the cause producing it. As a result of the interaction between the magnetic field produced by the induced eddy currents and the magnetic field of the electromagnet, a braking force is experienced which causes braking or retardation of the disc. This braking force is dependent upon the velocity of rotating disc. The braking force increases as the velocity of disc increases. When the metal plate enters the magnetic field, a Lorentz force,The force experienced by the electron in the disc causes induced current which in such a way that it opposes the cause producing it. Thus, induced current flows in closed paths. Certain papers [2] mention about the proposed models and the equations regarding the eddy current braking. They propose W.R. Smythe"s Model, D.Schieber"s Model and J.H. Wouterse"s Model.