Abstract: There is disclosed a cylinder wheel connected in rotary engagement with a ball-piston wheel, the cylinder wheel having a multiplicity of cylindrical cavities, each cavity having at least one coil with a plurality of electrically conductive turns circularly disposed therearound. The ball-piston wheel has a multiplicity of balls of magnetic material or permanent magnets which engage the cylindrical cavities. The coils may be periodically activated by selectively applying electric current thereto to sequentially propel each ball into and out of the respective cylindrical cavity thereby turning the cylinder wheel and ball-piston wheel in rotating motion. When the balls are magnets, and the cylinder and ball-piston wheel assembly is rotated by an external driving means, a voltage is induced in each coil as a permanent magnet ball passes therethrough thereby forming an electric generator.