Comparison of two- and three-phase motors

In the manufacture of induction motors considerations of cost make it advisable to build both two- and three-phase motors on the same size of frame. The questions then arise, given two similar frames without windings, how shall the two-and three-phase windings differ in order to secure proper operation? What will be the comparative losses if both machines are given the same rating, or, if not rated the same, how shall their ratings differ?