A quick overview on rotatory Brush and Brushless DC Motors

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INTRODUCTION
The electric motor in its simplest terms is a converter of electrical energy to useful mechanical energy. It operates on the principle that two magnetic fields within certain prescribed areas react upon each other. One field is produced by a permanent magnet assembly while the other field is produced by an electrical current flowing in the motor windings. These two fields result in a torque which tends to rotate the rotor. As the rotor turns, the current in the windings is commutated to produce a continuous torque output.

DC Brushed motors
DC brushed motors consist of a permanent magnet or a fixed electromagnet for a stator and a rotor with an armature with a set of windings[3].
Current is conducted to the windings through a set of slip-rings and brushes. The brushes make mechanical contact with a set of electrical contacts on the rotor (the commutator), forming an electrical circuit between the DC electrical source and the armature coil-windings.


DC Brushless Motors
All problems of brushed technology are eliminated in DC brushless motors (also known as BLDC). In these motors, the brush-system/commutator assembly is replaced by an electronic controller[5]. Magnets rotate and the current-carrying coils are stationary and energized sequentially to cause the rotor to turn. This introduces the need of an electronic drive controller to generate torque, which means more complex and sometimes expensive systems