Electromechanical conversation systems such as motors and generators relay upon magnetic field as their coupling medium due to its low energy. Though electrical field can also be used theoretically in electromechanical conversation, it poses high energy to establish a definite amount of field. This high energy coupling may be threat to mechanical equipment and needs extra insulation without which the shaft may conduct high leakage current. More over the creation of magnetic field some times requires
no energy as permanent magnets can be placed in slots. This reduces the extra consumption of energy for energy conversation.
According to Faraday Law, "when an current carrying conductor is placed in a magnetic field, it produces electo motive force EMF" or simply voltage that drives electrons to form current. The same law also states that "when current carrying conductor is kept in a magnetic field it experiences force or torque". The first law is applicable for generator and the second for the motor but you can observe one same parameter that is magnetic coupling.
Michael Faraday had developed this concept and the later research proved that these electromechanical conversation systems with magnetic coupling are efficient, rigid and reliable when compared with electric field coupling systems.
Venkat Satish Mamidisetti,
Power Plant Operations Engineer.