A motor control apparatus for controlling a power supply to an electrical motor (M) connected to an output terminal (3) of the motor control apparatus (1) comprising: an overcurrent protection circuit (1A) having a power switch (5) through which the electrical motor (M) receives an electrical load current (I.sub.L) and having a sensor component (4) connected in series with the power switch (5) and adapted to generate directly a voltage drop (?U.sub.4) corresponding to the current rise speed of the electrical load current (I.sub.L) flowing from an input terminal (2) of the motor control apparatus (1) via the sensor component (4) and the power switch (5) to the output terminal (3) and having a driver circuit (6) adapted to detect an occurring overcurrent depending on the voltage drop (?U.sub.4) generated by the sensor component (4) and/or depending on a voltage drop (?U.sub.5) along the power switch (5) and adapted to switch off said power switch (5) upon detection of an overcurrent within a switch-off period of less than one millisecond; and/or comprising a power supply control circuit (10) having a sensor component (9) adapted to measure at the input terminal (2) a supply voltage notified to a control unit (8) of the motor control apparatus (1) adapted to control an electrical power supplied to the electrical motor (M) depending on an operation mode of the electrical motor (M).

A load protection apparatus for protecting an electrical load connected to an output terminal of the load protection apparatus against overcurrent, includes an overcurrent protection circuit having a power switch through which the electrical load receives an electrical load current via the output terminal and having a sensor component connected in series with the power switch. The sensor component is adapted to directly generate a voltage drop corresponding to the current rise speed of the electrical load current flowing from an input terminal of the load control apparatus, via the sensor component and the power switch to the output terminal. The sensor component further includes a driver circuit adapted to detect an occurring overcurrent depending on the voltage drop generated by the sensor component and depending on a voltage drop along the power switch adapted to switch off said power switch upon detection of an overcurrent within a switch-off period.

A tool includes a device including a housing and a rotor, the rotor to rotate about a longitudinal axis, and an axial gap generator including a stator assembly positioned adjacent to the rotor. The axial gap generator generates a voltage signal as a function of a gap spacing between the stator assembly and the rotor, the gap spacing being parallel to the longitudinal axis.

A downhole-type system includes a rotatable shaft, a downhole-type magnetic bearing coupled to the rotatable shaft, a downhole-type sensor, a surface-type controller, and a surface-type amplifier coupled to the magnetic bearing. The magnetic bearing can control levitation of the rotatable shaft. The downhole-type sensor can detect a position of the rotatable shaft in a downhole location and generate a first signal based on the detected position. The surface-type controller can receive the first signal, determine an amount of force to apply to the shaft, and generate a second signal corresponding to the determined amount of force. The surface-type amplifier can receive the second signal, amplify the second signal to a sufficient level to drive the magnetic bearing to apply force to the rotatable shaft to control the levitation of the rotatable shaft at the downhole location, and transmit the amplified second signal to the magnetic bearing.

A fluid rotor is configured to move or be rotated by a working fluid. A fluid stator surrounds the fluid rotor. The fluid stator is spaced from the fluid rotor and defines a first annular fluid gap in-between that is in fluid communication with an outside environment exterior the downhole-type pump. A radial magnetic bearing includes a first portion coupled to the fluid rotor and a second portion coupled to the fluid stator. The first portion is spaced from the second portion defining a second annular fluid gap in-between that is in fluid communication with the outside environment exterior the downhole-type pump.

A downhole-type system includes a rotatable rotor, a magnetic thrust bearing coupled to the rotor, and a mechanical thrust bearing coupled to the rotor. The magnetic thrust bearing is configured to support a first portion of an axial load of the rotor during rotor rotation, and the mechanical thrust bearing is configured to support a second portion of the axial load of the rotor during rotor rotation.

A fluid module includes a fluid rotor configured to rotatably drive or be driven by fluid produced from a wellbore. A first shaft is coupled to the fluid rotor. The first shaft is configured to rotate in unison with the fluid rotor. A thrust bearing module includes a thrust bearing rotor. A second shaft is coupled to the thrust bearing rotor. The second shaft is configured to rotate in unison with the thrust bearing rotor. The second shaft is coupled to the first shaft. An electric machine module includes an electric machine rotor. A third shaft is coupled to the electric machine rotor. A third shaft is configured to rotate in unison with the electric machine rotor. The third shaft is coupled to the second shaft. The third shaft is rotodynamically isolated from the first shaft and the second shaft.

A device includes a rotor to rotate about a longitudinal axis, a magnetic bearing actuator, and an axial gap generator including a stator assembly adjacent to the rotor, the axial gap generator to generate an amount of power as a function of a gap spacing between the stator assembly and the rotor, the gap spacing parallel to the longitudinal axis, and the axial gap generator to supply the amount of power to a control coil of the magnetic bearing actuator.

A downhole-type system includes a rotatable shaft; a sensor that can sense an axial position of the shaft and generate a first signal corresponding to the axial position of the shaft; a controller coupled to the sensor, in which the controller can receive the first signal generated by the sensor, determine an amount of axial force to apply to the shaft to maintain a target axial position of the shaft, and transmit a second signal corresponding to the determined amount of axial force; and multiple magnetic thrust bearings coupled to the shaft and the controller, in which each magnetic thrust bearing can receive the second signal from the controller and modify a load, corresponding to the second signal, on the shaft to maintain the target axial position of the shaft.

A system to provide power to a downhole-type tool includes a downhole-type electric motor that can be positioned in a wellbore and a variable speed drive electrically connected to the electric motor, in which the downhole-type electric motor can operate at rotary speeds of at least 6,000 rotations per minute (rpm), the variable speed drive can control and supply power to the electric motor when the electric motor is positioned at a downhole location inside the wellbore, and the variable speed drive can be at a surface of the wellbore.