ABSTRACT
This chapter discusses the direct-current generators, driven by AC motors called 'motor-generator', used to convert alternating current into direct current. The development of reliable and inexpensive solid-state rectifier devices, direct-current generators is superseded by alternating-current generators that changes from AC to DC. In a DC generator, the rotating armature loop is connected to its external load by a split-ring commutator and spring-loaded carbon brushes. The purpose of the springs is to hold the carbon brushes against the rotating commutator. All the energy losses that occur in a DC generator must be dissipated by heat transfer away from the machine in order to limit the rise in the machine's temperature. The function of machine's magnetic circuit is to support the armature windings into which the generator's output voltage is induced. The chapter applies Fleming's right-hand rule to the active conductors as they rotate clockwise and the load current flows through the conductors in the directions shown by the 'cross/dot' notation.
