# Theory of DC Machines

##### Director of Generator and Motor action
Converter that is used to incessantly transform electrical energy to mechanical energy or the other way around is referred to as electric machines. The method of conversion is understood as mechanical device energy conversion. An electrical machine is thus a link amongst an electrical system network and a machine driven system. In this machine the conversion is revocable. If the transformation is from mechanical energy to electrical energy, then the machine is alleged to performance as a generator. If the transformation is from electrical power to Mechanical power, then the machine is alleged to act as a motor. The above diagram represents both the motor and generator conversion action.
In these machines, transformation of power from electrical to mechanical forms or the other way around results from the subsequent 2 magnetic force phenomena:
• Once a conductor moves in a magnetic field, emf is induced within the conductor. This action is called as Generator action.
• Once a current carrying conductor is placed in a magnetic field, the conductor - experiences a mechanical force.  This action is called as Motor action.
These 2 effects occur at the same time when energy transformation takes place from mechanical to electrical or electrical to mechanical. In driving action (motoring), the electrical system creates current flow over conductors that are engaged within the magnetic fields. A force is made on every conductor. If the conductors are placed on a structure liberal to rotate, a magnetic torque is made, tending to create the revolving structure revolve at certain speed. If the conductors rotate in a magnetic field, a voltage will be induced in every conductor. In generating action, the method is reversed. During this case, the revolving structure, the rotor is driven by a prime mover. A voltage will be induced in the conductors that are spinning with the rotor. If an electrical load is connected in the winding shaped by these conductors, a current will be able to flow, delivering power to the load. Moreover, this passing over the conductor can move with the magnetic field to supply a reaction torque, which can have a tendency to oppose the force (torque) applied by the prime mover.