A downhole electric motor for a submersible pump has at least three phases
and comprises a permanent magnet rotor and a stator bearing phase
windings A, B and C in slots (2206) in the stator. Each phase winding A,
B, C incorporates a coil extending through a respective pair of adjacent
stator slots (2206) and surrounds a respective portion of the stator
between the slots (2206). Furthermore adjacent coils of each pair of
phase windings A, B, C extend through opposite parts of a respective one
of the slots (2206), so that these coils extend alongside one another in
the slot, either being separated by a gap through which cooling fluid may
be pumped to cool the coils, or being separated by a thermally conductive
projection (3110), with which the coils are in thermal contact, extending
at least part of the way across the slot. Such a winding arrangement is
advantageous in ensuring that the motor has a long life.