Brushless AC electric motor

A Brushless AC electric motor, also known as a permanent magnet synchronous motor

Synchronous motor

A synchronous electric motor is an AC motor distinguished by a rotor spinning with coils passing magnets at the same rate as the power supply frequency and resulting rotating magnetic field which drives it....

 (PMSM), is similar to a brushless DC electric motor

Brushless DC electric motor

Brushless DC motors also known as electronically commutated motors are electric motors powered by direct-current electricity and having electronic commutation systems, rather than mechanical commutators and brushes...

 in that the magnetic field of the rotor is supplied by the permanent magnets rather than by electromagnet

Electromagnet

An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off...

s. However, the stator windings of a brushless AC motor are sinusoidally distributed windings, while those of a brushless DC motor are salient field coil

Field coil

A field coil is a component of an electro-magnetic machine, typically a rotating electrical machine such as a motor or generator. A current-carrying coil is used to generate a magnetic field....

s.