Patent ID: 6191561
Filing Date: 2001-02-20
Classification: E21B,H02K,H02P

Abstract:
An apparatus for generating variable downhole electrical energy from a rotating shaft, comprising:a drive shaft having a longitudinal drive shaft axis;a first permanent magnet fixedly attached to said drive shaft and comprising a first plurality of longitudinal permanent magnetic segments having magnetizations circumferentially alternating between north pointing inward toward said drive shaft axis and north pointing outward away from said drive shaft axis;a second permanent magnet movably mounted on said drive shaft axially adjacent to said first permanent magnet and comprising a second plurality of longitudinal permanent magnetic segments having magnetizations circumferentially alternating between north pointing inward toward said drive shaft axis and north pointing outward away from said drive shaft axis;a main armature surrounding at least a portion of each of said first and second permanent magnets and having windings for generating electrical output due to the rotation of said first and second permanent magnets within said main armature; anda regulator operably connected to said second permanent magnet for regulating said electrical output by varying the position of said second permanent magnet with respect to said first permanent magnet;wherein said regulator may vary the axial separation of said second permanent magnet with respect to said first permanent magnet between a first relative position for which said electrical output is a minimum value and a second relative position for which said electrical output is a maximum value.