Patent ID: 7777386

Claim:
A stator assembly adapted for use in an external rotor electric motor, said assembly comprising: a stator core having a hub, a plurality of teeth extending radially outward from the hub, a root tooth diameter and an outer diameter, each tooth of said plurality of teeth having a root, a neck extending from the root and a head opposite the root, said neck having a maximum width, and each adjacent pair of teeth of said plurality of teeth has a pitch measured at the roots of the corresponding teeth; and a winding wrapped around each tooth of at least three teeth of said plurality of teeth of the stator core; wherein the outer diameter of the stator core is between about 220 mm and about 300 mm; wherein a ratio of the root tooth diameter of the stator core to the outer diameter of the stator core is less than about 0.7; and wherein a ratio of the maximum tooth neck width to the tooth pitch measured at the root of the teeth is greater than about 0.36.