A method for controlling a permanent magnet (PM) synchronous motor in an ESP application is provided. A load angle of the PM motor is estimated. A voltage adjustment value is determined for the PM motor based at least on the estimated load angle of the PM motor. A voltage to be applied to the PM motor is determined based on the voltage adjustment value.

Systems and methods for testing downhole power cables wherein such systems and methods utilize a mounting bracket having a PEEK insulator extending from a first face of said bracket and at least one flexible lead extending from a second face of said bracket. Such systems and methods may accommodate three such flexible leads that are configured to interface with power cables. A shunting block may be incorporated in a protective cap configured to fit over the PEEK insulator extension from said first face of said bracket.

A closed loop heat exchanger system for use with an outboard motor, wherein the heat exchanger assembly is disposed in the housing portion of the lower drive unit of the outboard motor where the propulsion assembly resides. The heat exchanger assembly being in thermal communication with the external surface of the housing of the lower drive unit, thus eliminating the need for an external raw water intake on the lower housing portion and reducing or eliminating components associated with a raw water pump system.

A closed loop heat exchanger system for use with an outboard motor, wherein the heat exchanger assembly is disposed in the housing portion of the lower drive unit of the outboard motor where the propulsion assembly resides. The heat exchanger assembly being in thermal communication with the external surface of the housing of the lower drive unit, thus eliminating the need for an external raw water intake on the lower housing portion and reducing or eliminating components associated with a raw water pump system.

An electrically-propelled marine vehicle and method of making same, including providing a hull of the marine vehicle and mounting a submersible electric thruster to the hull. The thruster includes a stator assembly and a rotor assembly. The rotor assembly forms an internal cavity with a plurality of magnets arranged radially outwardly of the internal cavity. The stator assembly includes electrical windings that are disposed within the internal cavity of the rotor assembly. The thruster is configured to allow the internal cavity to be flooded with water when the thruster is submerged, and the electrical windings are covered by a protective barrier that prevents the flooded water from contacting the windings. The thruster of the marine vehicle is thus water cooled, and the electromotive forces provided by the windings generate sufficient thrust to propel the marine vehicle through the water.

An electrically-propelled marine vehicle and method of making same, including providing a hull of the marine vehicle and mounting a submersible electric thruster to the hull. The thruster includes a stator assembly and a rotor assembly. The rotor assembly forms an internal cavity with a plurality of magnets arranged radially outwardly of the internal cavity. The stator assembly includes electrical windings that are disposed within the internal cavity of the rotor assembly. The thruster is configured to allow the internal cavity to be flooded with water when the thruster is submerged, and the electrical windings are covered by a protective barrier that prevents the flooded water from contacting the windings. The thruster of the marine vehicle is thus water cooled, and the electromotive forces provided by the windings generate sufficient thrust to propel the marine vehicle through the water.

An electric submersible pumping system includes a motor filled with motor lubricant, a pump driven by the motor, and a fluid expansion chamber connected to the motor. The fluid expansion chamber includes a seal bag filled with a seal bag lubricant and a bellows contained within the seal bag. The bellows includes an interior in fluid communication with the motor and an exterior in fluid communication with the seal bag lubricant.

An electric submersible pumping system includes a motor filled with motor lubricant, a pump driven by the motor, and a fluid expansion chamber connected to the motor. The fluid expansion chamber includes a seal bag filled with a seal bag lubricant and a bellows contained within the seal bag. The bellows includes an interior in fluid communication with the motor and an exterior in fluid communication with the seal bag lubricant.

A method comprises operating an electric submersible pump (ESP) motor downhole in a well. The ESP motor is electrically connected to a variable speed drive (VSD) proximate to the well. The operating comprises measuring a revolution rate and a motor current of the ESP motor for a first period of time and performing a first adjustment of a voltage output of the VSD. The method comprises measuring, after the first adjustment, the revolution rate and the motor current of the ESP motor for a second period of time determining a difference between the motor current measured for the first period of time and the motor current measured for the second period of time; and performing a second adjustment of the voltage output of the VSD based on a change in the revolution rate and the motor current between the first period of time and the second period of time.

A method comprises operating an electric submersible pump (ESP) motor downhole in a well. The ESP motor is electrically connected to a variable speed drive (VSD) proximate to the well. The operating comprises measuring a revolution rate and a motor current of the ESP motor for a first period of time and performing a first adjustment of a voltage output of the VSD. The method comprises measuring, after the first adjustment, the revolution rate and the motor current of the ESP motor for a second period of time determining a difference between the motor current measured for the first period of time and the motor current measured for the second period of time; and performing a second adjustment of the voltage output of the VSD based on a change in the revolution rate and the motor current between the first period of time and the second period of time.