Single-phase or like alternating current electric motors

Claim 1

A VARIABLE SPEED SINGLE-PHASE OR LIKE ALTERNATING CURRENT MOTOR HAVING SHUNT CHARACTERISTICS WHICH INCLUDES ESSENTIALLY (A) AN ARMATURE CIRCUIT ADAPTED TO BE IMPRESSED BY AN ALTERNATING CURRENT VOLTAGE AND INCLUDING AN ARMATURE, ASSOCIATED WINDING, COMMUTATOR SEGMENTS AND BRUSHES, A RESISTOR CONNECTED IN SERIES BETWEEN THE ARMATURE WINDING AND EACH COMMUTATOR SEGMENT FOR IMPROVING COMMUTATION AND MINIMISING DISTORTION OF THE FIELD BY TRANSFORMER VOLTAGES IN PARTS OF THE ARMATURE WINDING BETWEEN THE COMMUTATOR SEGMENTS SHORT-CIRCUITED BY THE BRUSHES, AND A WINDING FOR NEUTRALISING ARMATURE REACTION, (B) A FIELD EXCITING WINDING CONSTRUCTED AND ARRANGED TO PRODUCE MAGNETIC FLUX THROUGH THE ARMATURE, (C) MEANS FOR MAINTAINING THE CURRENT IN AND FLUX OF THE FIELD EXCITING WINDING AUTOMATICALLY SUBSTANTIALLY IN PHASE WITH THE SUPPLY VOLTAGE APPLIED TO THE ARMATURE CIRCUIT COMPRISING, AN AUTO-TRANSFORMER SAID FIELD EXCITING WINDING BEING CONNECTED BETWEEN AN INTERMEDIATE TAP OF THE AUTO-TRANSFORMER AND ONE TERMINAL OF AN ALTERNATING CURRENT SUPPLY VOLTAGE THROUGH A SERIALLY CONNECTED CAPACITOR, SPEED ADJUSTABLE CONTROL MEANS FOR SIMULTANEOUSLY DERIVING FROM SAID SUPPLY VOLTAGE TWO VOLTAGES VARYING IN AMPLITUDE IN OPPOSITE DIRECTIONS AND APPLYING THEM TO THE TERMINALS OF THE AUTO-TRANSFORMER AND TO THE ARMATURE, RESPECTIVELY, TO VARY THE VOLTAGE APPLIED TO THE FIELD EXCITING WINDING IN A DIRECTION OPPOSITE TO THAT OF THE VOLTAGE APPLIED TO THE ARMATURE.