US Patent 6856053 Cooling of electrical machines

A stator for a high power density air gap electrical machine comprises an outer annular laminated iron stator core and a stator winding comprising a plurality of coils having linear conductor portions extending substantially parallel to a longitudinal axis of the machine. Support teeth for the coils are fabricated from a non-magnetic material, with each support being interposed between two adjacent ones of the linear conductor portions of the coils. The supports not only supplement the mechanical strength of the winding but also define channels for the flow of coolant to extract heat from the coils.