An electric motor is used for almost all mechanical movements nowadays. These are basically machines for producing mechanical energy from electrical energy. It can be broadly classified into DC Motors and AC Motors. Few examples where motors are used are: robots, automobiles, hand power tools etc. where small motors are used where as large motors are used in electric trains, hoists, heavy metal rolling mills etc. We shall be confining our discussion to small DC Motors here. Thus, as we know DC Motors (or Direct Current motors) are devices that covert direct current i.e., electrical energy into any form of mechanical energy (mostly rotation).