Brushless DC motor having multiple stator windings

Claim 1

In a brushless d-c motor of the type having a permanent magnet rotor and a stator winding made up of several phase windings with the phase windings Y-connected on one side and provided to one side of a voltage source with the other side of the phase windings coupled through individual power transistors to the other side of the voltage source with each power transistor controlled by a separate control device which is responsive to a rotor position transducer, an improved arrangement for providing such a motor with a power rating in excess of that obtainable through the use of a single transistor in each phase winding the improvement comprising: a. each phase winding sub-divided into an equal number of winding legs with the winding legs belonging to a phase winding arranged in the stator in two groups of equal size diametrically opposite each other with said two groups electrically connected in such a manner that the magnetic fluxes generated by them act in the same direction; b. the power transistors coupling said phase winding including a separate power transistor coupling each of the winding legs to the other side of the voltage source; and c. the separate control device for each phase winding coupled to simultaneously energize and deenergize all transistors associated with the legs making up an individual phase winding.