Patent ID: 8047306
Filing Date: 2011-11-01
Classification: H02K

Abstract:
1. A top drive drilling system, comprising: an electric motor capable of producing sufficient torque to rotate a drill string and a drill bit during drilling operations, wherein the electric motor includes a hollow shaft; a stator assembly comprising a plurality of stator laminates compressed into a plurality of stator packs, the stator packs being longitudinally spaced to form radially directed channels for the movement of cooling air or fluid; a rotor assembly comprising a plurality of rotor laminates compressed into a plurality of rotor packs, the rotor packs being longitudinally spaced to form radially directed channels for the movement of cooling air or fluid; a pulse width modulated variable speed drive for generating a signal to drive the electric motor at the desired speed of the drill bit, thereby avoiding speed reduction equipment; and a cooling system of one or more cooling fans with output directed to supply cooling air, said cooling air is passed through the said radially directed channels in said stator and rotor assemblies.