摘要 |
An electric motor, for powering downhole tools, comprises a stator and a rotor connectable to a rotatable device, a permanent magnet and a series of coiled windings or laminations having a connection to a DC supply, the permanent magnet and the laminations being arranged annularly with respect to each other, characterised in that the laminations and coil windings are potted in a potting material impervious to wellbore fluids. The potting material are introduced under a vacuum, and the motor housing confines the potting material, acting as a mould. |