Commonly, freight cars have no available source of electric power, thus preventing the use of any electronic devices that could improve convenience, performance, and efficiency of railroad operations. The devices introduced in this paper are motion-based electromagnetic energy harvesting systems. Similar in size and shape to a conventional damper or shock absorber, the systems are to be placed in the coil spring of the suspension to convert part of the energy usually wasted as heat into useful electric energy. This paper will present the design, development and testing of such devices. Tests of prototype devices on a shock dynamometer show that more than 20 Watts RMS of power can be produced with motions that can be encountered in train suspensions. The devices presented, although primarily developed for railroad applications, are not limited to use in freight cars and could be similarly applied in various vehicles with suspension like tractor-trailers, buses or automobiles.
A low frequency rotational energy harvesting system
