Patent ID: 8851864

Claim:
An electric submersible pump assembly comprising: a rotary primary pump; a motor operationally coupled to the primary pump for driving the pump; a cylindrical stator defining a cylindrical central cavity having an axis, the stator positioned within the motor; a rotor having a length and positioned within the central cavity of the stator; rotor radial bearings positioned along the length of the rotor within the stator to allow rotation of the rotor relative to the stator; wherein rotation of the rotor relative to the stator causes at least one location of high amplitude vibration of the rotor; a thrust bearing comprising a piston positioned to axially support the rotor; a hydraulic pressure chamber positioned axially adjacent the piston so that the piston is axially supported by pressure within the pressure chamber; a capillary tube communicatively coupled to the pressure chamber and extending alongside and upward from the motor; and a hydraulic pressure pump located above the motor and connected to the capillary tube for supplying hydraulic pressure to the pressure chamber in an adjustable amount to adjust an axial position of the rotor and the rotor radial bearings such that none of the radial bearing are located at the location of high amplitude vibration.