Brushed DC motors have their coil windings in the rotor. As the rotor rotates, the brush connections switch between commutators, thereby switching the flow of electrical current through each coil.By switching the direction of electrical current flow at appropriate times, the rotor is able to rotate continuously.Principle of operation of a brushless DC motorA brushless DC motor avoids the need for a commutator and brushes by having its permanent magnets in the rotor. Rotation of the rotor is maintained by detecting the position of the rotor magnetic poles and switching the electric current flow through the coils accordingly. For this reason, a brushless DC motor requires a driver (an electronic drive circuit). The detection of rotor shaft position, meanwhile, is done using a hall effect sensor or other magnetic sensors (although sensorless motors also exist that are able to work without such a sensor).Hall effect sensors uses the hall effect to determine magnetic field strength. By converting this into an electrical signal, the driver is able to detect the position of the permanent magnet (the orientation of its north and south poles) and switches the electric current flow through its coils in such a way that it keeps the motor shaft rotating.