Investigation on Eddy Current Braking Systems – A Review

Abstract

The changing magnetic field will induce eddy currents in the conductor. These currents will dissipate energy in the conductor and generate drag force. It is found that Aluminium is the best material as conductor compared to Copper and Zinc. Also, it is found that the larger thickness of disc, more number of turns of electromagnet and higher electrical conductivity of conductor influences the generation of greater braking torque. Conventional braking system relies on adhesion force between rail and wheel. It is found that a brake built up from permanent magnet pieces that combine both magnetic rail brake and eddy current brake permits the most profitable braking action through the whole range of acceptable speeds. Permanent magnet eddy current brake uses Neodymium - Iron - Boron (NdFeB) magnets. The analysis of permanent magnet eddy current shows that the parallel magnetised eddy current topology has the superior braking torque capability. In electrically controlled eddy current braking system subjected to time varying fields in different wave forms, the triangular wave field application resulted in highest braking torque. Electromagnetic brakes were found to interfere with the signalling and train control system. Permanent magnet eddy current brakes are a simple and reliable alternative to mechanical or electromagnetic brakes in transportation applications. Greater the speed greater is the eddy current braking efficiency. Hence, author intends to work on the development and investigation of permanent magnet eddy current braking system.