Speed control circuit for electronically commutated dc motor

Claim 1

A SPEED CONTROL CIRCUIT FOR AN ELECTRONICALLY COMMUTATED DC MOTOR HAVING A FIRST PHASE AND A SECOND PHASE, A FIRST PHASE STATOR WINDING AND A SECOND PHASE STATOR WINDING, SAID FIRST PHASE STATOR WINDING BEING DIVIDED INTO TWO WINDING PORTIONS, SAID SECOND PHASE STATOR WINDING BEING DIVIDED INTO TWO WINDING PORTIONS, FIRST CONNECTING MEANS CONNECTING ONE OF THE WINDING PORTIONS OF SAID FIRST PHASE STATOR WINDING TO ONE OF THE WINDING PORTIONS OF SAID SECOND PHASE STATOR WINDING, SECOND CONNECTING MEANS CONNECTING THE OTHER OF THE WINDING PORTIONS OF SAID FIRST PHASE STATOR WINDING TO THE OTHER OF THE WINDING PORTIONS OF SAID SECOND PHASE STATOR WINDING, THIRD CONNECTING MEANS CONNECTING A COMMON POINT OF SAID FIRST CONNECTING MEANS WITH A COMMON POINT OF SAID SECOND CONNECTINT MEANS, A PLURALITY OF SWITCHING TRANSISTORS EACH HAVING EMITTER, COLLECTOR AND BASE ELECTRODES, AN EMITTERCOLLECTOR PATH AND AN EMITTER-BASE PATH, A FIRST OF SAID TRANSISTORS BEING CONNECTED WITH ITS EMITTER-COLLECTOR PATH IN SERIES WITH ONE OF THE WINDING PORTIONS OF SAID FIRST PHASE STATOR WINDING, A SECOND OF SAID TRANSISTORS BEING CONNECTED WITH ITS EMITTER-COLLECTOR PATH IN SERIES WITH THE OTHER OF THE WINDING PORTIONS OF SAID FIRST PHASE STATOR WINDING, A THIRD OF SAID TRANSISTORS BEING CONNECTED WITH ITS EMITTER-COLLECTOR PATH IN SERIES WITH ONE OF THE WINDING PORTIONS OF SAID SECOND PHASE STATOR WINDING, A FOURTH OF SAID TRANSISTORS BEING CONNECTED WITH ITS EMITTER-COLLECTOR PATH IN SERIES WITH THE OTHER OF THE WINDING PORTION OF SAID SECOND PHASE STATOR WINDING, OPERATING VOLTAGE MEANS FOR APPLYING A DC OPERATING VOLTAGE BETWEEN ONE OF SAID FIRST AND SECOND TRANSISTORS AND ONE OF SAID THIRD AND FOURTH TRANSISTORS, FIRST AND SECOND HALL GENERATORS POSITIONED IN DETERMINED RELATION IN A MAGNETIC FIELD OF SAID DC MOTOR