Brushless AC electric motor
A brushless motor is an electric motor without brushes ( sliding contacts ). For brushless motors is between the movable rotor and the stationary stator no electrical contact.
The brushes are used for electrical connection between the rotor and stator via slip rings or commutator and subject by the mechanical abrasion and the brush fire to wear. When brushless electric motor accounts for slip rings or commutator and the brushes, such an engine has a longer life on.
The brushless machines include some types of rotating electrical machines such as the three-phase asynchronous squirrel-cage motors. The rotary motion is caused by the generated in the stationary stator rotating field.
The brushless DC motor, basically, a synchronous machine with electronic phase sequence generation, the magnetic excitation is effected by means of permanent magnets.
Synchronous machines with separate excitation often have slip rings on as part of a static excitation equipment. To avoid the slip rings, there is the possibility of a brushless exciter device.