PERMANENT MAGNET BRUSHLESS D.C.
DC motors are highly efficient and their characteristics make them suitable for
use as servomotors. However, their only drawbacks that they need a commutator
and brushes which are subject to wear and require maintenance.
functions of commutator and brushes were implemented by solid state switches,
maintenance free motors were realized. These motors are known as brushless DC
motors. The function of magnets is the same in both brushless motor and the dc
commutator motor. The motor obvious advantage of brushless configuration is the
removal of brushes. Brush maintenance is no longer required, and many problems
associated with brushes are removed.
advantage of the brushless configuration in which the rotor inside the stator
is that more cross sectional area is available for the power or armature
winding. At the same time conduction of heat through the frame is providing
greater specific torque. The efficiency is likely to be higher that of a
commutator motor of equal size and the absence of brush friction help further
in this regard.