Abstract: A new and improved linear motor and method of using it for producing a sufficient reciprocating thrusting action to enable well fluids be pumped through the production tubing of a well to the ground surface. The linear motor includes a mover and a stator, said stator including a set of coils for producing a series of electromagnetic field extending at least partially in an axial direction when energized with an electric current and a stator core defining a plurality of spaced-apart transversely disposed coil receiving slots and an annular axially extending mover receiving bore. The mover includes an elongated member mounted telescopically reciprocatively within the mover receiving bore and a plurality of permanent magnets interleaved with low reluctance spacers for helping to reduce core flux density in order to improve overall motor performance.

Abstract: A new and improved control system for monitoring and controlling the operation of a downhole linear d.c. motor-pump assembly and a method of using it for producing a sufficient reciprocating pumping action to lift well fluid through the producing tubing of a well to the ground surface. The system includes a surface monitoring station that is in radio communication with a plurality of remote downhole motor-pump assemblies. Each motor-pump assembly has a surface motor controller, a downhole motor-pump cartridge unit that is adapted to be received in a downhole cartridge sleeve assembly that maintains the cartridge unit in a stationary position for pumping purposes. The motor-pump cartridge unit may be raised or lowered by a control cable within the production tubing for helping to facilitate the repair or replacement of the motor-pump cartridge unit.