Patent ID: 7119471

Claim:
A synchronous motor ( 10 , 110 ) comprises: a housing ( 20 , 120 ); a stator assembly ( 30 , 130 ) mounted within the housing ( 20 , 120 ); a rotor assembly ( 40 , 140 ) rotationally mounted within the housing ( 20 , 120 ); a rotor shaft ( 50 , 150 ) having an upper mounting surface ( 52 , 152 ) and attached to the rotor assembly ( 40 , 140 ); a bearing assembly ( 60 , 160 ) coupled to the housing ( 20 , 120 ) and the rotor shaft ( 50 , 150 ), wherein the bearing assembly ( 60 , 160 ) is positioned axially between the rotor assembly ( 40 , 140 ) and the upper mounting surface ( 52 , 152 ); a slip ring assembly ( 70 , 170 ) supported by the housing ( 20 , 120 ) and positioned axially at least partially within the stator assembly ( 30 , 130 ) and the rotor assembly ( 40 , 140 ); and an encoder assembly ( 80 , 180 ) adjacent the slip ring assembly ( 70 , 170 ), wherein the outer diameter of the motor ( 10 , 110 ) is no greater than about 24″ and a height of the motor ( 10 , 110 ) is less than about 20″.