Synchronous motors

Claim 1

AN A.C. SYNCHRONOUS MOTOR HAVING HIGH EFFICIENCY AND HIGH TORQUE CHARACTERISTICS COMPRISING: A FIELD COIL WOUND IN A CYLINDRICAL FORM AROUND AN AXIS FOR PRODUCING ALTERNATING MAGNETIC FLUX; CIRCULARLY SYMMETRICAL STATOR MEANS OF LOW RELUCTANCE MAGNETIC MATERIAL MOUNTED CONCENTRICALLY WITH SAID COIL AND IN MAGNETIC CIRCUIT RELATION THEREWITH FOR GUIDING SAID FLUX, SAID STATOR MEANS INCLUDING A CUP-LIKE PORTION FORMING A MAGNETIC PATH EXTENDING RADIALLY OUTWARD NEAR AN END OF SAID COIL AND THEN LONGITUDINALLY ALONG SAID COIL OUTSIDE THE SAME TO A SMOOTHLY CONTOURED, OR NON-SALIENT, EDGE REGION, AND A PLURALITY OF SPACED FINGER-LIKE POLE MEMBERS OF THE SAME INSTANTANEOUS MAGNETIC POLARITY EXTENDING FROM THE OTHER END OF SAID COIL LONGITUDINALLY ALONG SAID COIL OUTSIDE THE SAME; THE EDGE REGION OF SAID CUP-LIKE PORTION AND THE ENDS OF SAID POLE MEMBERS OVERLAPPING SO AS TO LEAVE INBETWEEN A NARROW ANNULAR AIR GAP CONCENTRIC WITH SAID COIL; AND A PERMANENT-MAGNETIC DISC-SHAPED ROTOR OF LARGER DIAMETER THAN SAID FIELD COIL HAVING A PLURALITY OF POLES OF ALTERNATE POLARITY SPACED AROUND A PERIPHERAL RING FORMED OF MAGNETIZABLE FERRITE MATERIAL, SAID ROTOR BEING CONCENTRICALLY MOUNTED FOR ROTATION IN THE MAGNETIC FIELD PROVIDED IN SAID AIR GAP BY SAID FIELD COIL AND SAID STATOR MEANS, AND SAID MAGNETIC FIELD BEING DIRECTED TRANSVERSE TO THE AXIS OF SAID FIELD COIL; SAID STATOR MEANS, SAID AIR GAP, AND SAID ROTOR FORMING THEREBY A CLOSED PATH OUTSIDE SAID FIELD COIL OF VERY LOW LEAKAGE FOR SAID ALTERNATING MAGNETIC FLUX.