Pressurized bearing system for submersible motor

An electric submersible pump assembly for a well, the assembly comprising:

• an electrical motor having a shaft, a bearing located within a housing adapted to be filled with lubricant, and passages communicating the shaft and the bearing;
• a chamber located in a lower portion of the housing for containing a volume of lubricant;
• a flow passage within the shaft leading from the chamber to the bearing;
• first and second centrifugal lubricant pump stages, each pump stage located in the housing and each having an impeller attached to and rotating with the shaft and a mating diffuser for pressurizing the lubricant;
• wherein
• the diffuser in the first pump stage leads to the impeller in the first stage, the impeller of the first stage leads to the diffuser of the second stage, the diffuser of the second stage leads to the impeller of the second stage, and the impeller of the second stage leads to the chamber;
• and
• a pump exterior of the motor and connected to the shaft for pumping well fluid.