Electronically commutated (EC) motors are highly efficient, programmable, brushless DC motors utilizing a permanent magnet rotor and a built-in inverter. Basically, it is a DC motor (in a DC motor the mechanical commutation switches the direction of the current) with a built-in VFD and a DC to AC transformer. However in EC motors, the mechanical commutation and the brushes are replaced by an electrical commutation. The major advantages are that they are extremely efficient, especially at reduced speeds compared to traditional motors. Also, they have a built-in speed controller eliminating the need for a separate VFD. (At this time they are only available up to about 6.5 hp.)