| 摘要 |
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.
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