Abstract: An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

Abstract: Systems and methods for reclaiming and remagnetizing permanent magnet motors such as may be used in electric submersible pumps. In one embodiment, a method includes removing a permanent magnet rotor assembly from a motor and heating the rotor to burn off the residual oil and evaporate water in between laminations of the rotor and on the rotor surface. The rotor should be heated to a temperature that is above a flashpoint of oil on the rotor and below a Curie temperature of a material of a set of permanent magnets in the rotor (e.g., at least 600° F. for at least 12 hours). The heating may partially or fully demagnetize the permanent magnets in the rotor. The exposed surfaces of the rotor are then cleaned and the permanent magnets in the rotor are remagnetized using a specialized magnetizing fixture.

Abstract: Systems and methods for reclaiming and remagnetizing permanent magnet motors such as may be used in electric submersible pumps. In one embodiment, a method includes removing a permanent magnet rotor assembly from a motor and heating the rotor to burn off the residual oil and evaporate water in between laminations of the rotor and on the rotor surface. The rotor should be heated to a temperature that is above a flashpoint of oil on the rotor and below a Curie temperature of a material of a set of permanent magnets in the rotor (e.g., at least 600° F. for at least 12 hours). The heating may partially or fully demagnetize the permanent magnets in the rotor. The exposed surfaces of the rotor are then cleaned and the permanent magnets in the rotor are remagnetized using a specialized magnetizing fixture.

Abstract: An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

Abstract: An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

Abstract: Systems and methods for reclaiming and remagnetizing permanent magnet motors such as may be used in electric submersible pumps. In one embodiment, a method includes removing a permanent magnet rotor assembly from a motor and heating the rotor to burn off the residual oil and evaporate water in between laminations of the rotor and on the rotor surface. The rotor should be heated to a temperature that is above a flashpoint of oil on the rotor and below a Curie temperature of a material of a set of permanent magnets in the rotor (e.g., at least 600° F. for at least 12 hours). The heating may partially or fully demagnetize the permanent magnets in the rotor. The exposed surfaces of the rotor are then cleaned and the permanent magnets in the rotor are remagnetized using a specialized magnetizing fixture.

Abstract: An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

Abstract: A submersible well pump assembly has a pump driven by an electrical motor. The motor has a number of rotor sections axially separated from each other by radial bearings. Each of the rotor sections has disks stacked together, each of the disks having a central opening and slots circumferentially spaced around the central opening. Metal rods extend through the slots. A center tube extends through the central openings of the disks. The center tube has an outer diameter in an interference fit with the disks. A slot and key arrangement between the inner diameter of the center tube and the motor shaft rotates the motor shaft in unison. The ends of the center tube extend past end rings of the rotor sections and abut with center tubes of adjacent rotor sections.

Abstract: Systems and methods for constructing permanent magnet electric motors in which rotors have magnetically permeable end rings that are active for torque production. In one embodiment, a rotor section has a set of flat, generally annular laminations stacked on an inner rotor sleeve, with a pair of end rings positioned at opposing ends of the lamination stack to secure the stack. One or both of the end rings is made of a magnetically permeable and highly resistive material such as a soft magnetic composite, so that the end ring(s) actively produce torque during operation of the motor without significant increase in core loss at end rings. A set of permanent magnets are installed in or on the rotor core formed by the laminations. These magnets or other magnets may be positioned to axially overlap with the end rings and aid active torque production by the end rings.

Abstract: A subsea pump assembly includes a tubular conduit that has an upstream end plate and an inlet for flowing well fluid into an interior of the conduit. A power cable opening extends through the upstream end plate. An electrical submersible pump and motor are in the interior of the conduit. The motor has a motor assembly housing with an upstream end having an electrical insulator opening. An end connection secures the upstream end to an interior side of the upstream end plate with the insulator opening registering with the power cable opening. An insulated electrical connector is mounted in the insulator opening. A motor wire in the motor assembly housing joins to an inner end of the electrical connector. A power conductor extends from exterior of the conduit through the power cable opening and joins to an outer end of the electrical connector.

Abstract: Systems and methods for reducing vibration in an electric motor using rotor bearing assemblies that are positioned within a bore of the stator to support the motor's shaft and rotor sections so that they can rotate within the stator bore. Each rotor bearing assembly includes an outer bearing and an inner bearing sleeve that rotates within the bearing. The bearing is secured so that its rotation within the stator is inhibited, but it can move axially. Each end of the bearing sleeve has a conically tapered contact surface which contacts and secures the corresponding rotor section and centers the rotor section with respect to the axis of rotation of the bearing. The contact surfaces of the rotor sections may be chamfered at an angle complementary to the tapered contact surface of the bearing sleeve to distribute the contact pressure between them over a greater contact surface area.

Abstract: Systems and methods for constructing permanent magnet electric motors in which rotors have magnetically permeable end rings that are active for torque production. In one embodiment, a rotor section has a set of flat, generally annular laminations stacked on an inner rotor sleeve, with a pair of end rings positioned at opposing ends of the lamination stack to secure the stack. One or both of the end rings is made of a magnetically permeable and highly resistive material such as a soft magnetic composite, so that the end ring(s) actively produce torque during operation of the motor without significant increase in core loss at end rings. A set of permanent magnets are installed in or on the rotor core formed by the laminations. These magnets or other magnets may be positioned to axially overlap with the end rings and aid active torque production by the end rings.

Abstract: Systems and methods for constructing electric motors in which rotor sections are individually keyed to a rotor shaft such that, in a resting position, the rotor sections are circumferentially shifted (“clocked”) with respect to each to mitigate effects of harmonic feedback, torsional flexibility and the like. In one embodiment, a system includes an electric drive, and an ESP coupled to it by a power cable. The ESP motor has a rotor in which multiple permanent-magnet rotor sections are mounted to a shaft. Within each rotor section, permanent magnets are positioned in two or more axially aligned rows. Adjacent rotor sections are clocked with respect to each other so that, in operation, the rows of permanent magnets in the different rotor sections are positioned to counter the harmonic feedback or to use torsional deflection to equalize torque contributions from the different rotor sections.

Abstract: Systems and methods for connecting power cables to downhole equipment such as ESPs using side-exit (radial) connections. In one embodiment, a system includes an electric drive coupled by a power cable to an ESP. The electric drive is positioned at the surface of a well with the power cable coupled to it. The power cable extends into the well bore and is coupled to the downhole equipment which is positioned in the well bore. The power cable has a connector with a first set of radially oriented terminals (the terminals are perpendicular to the conductors of the power cable). These terminals engage a second set of terminals that are installed in the downhole equipment. The radial orientation of the terminals of the connector and downhole equipment allow the power cable to remain axially oriented, thereby facilitating engagement of the terminals and requiring less annular space in the well bore.

Abstract: A submersible well pump assembly has a pump driven by an electrical motor. The motor has a number of rotor sections axially separated from each other by radial bearings. Each of the rotor sections has disks stacked together, each of the disks having a central opening and slots circumferentially spaced around the central opening. Metal rods extend through the slots. A center tube extends through the central openings of the disks. The center tube has an outer diameter in an interference fit with the disks. A slot and key arrangement between the inner diameter of the center tube and the motor shaft rotates the motor shaft in unison. The ends of the center tube extend past end rings of the rotor sections and abut with center tubes of adjacent rotor sections.

Abstract: A subsea pump assembly includes a tubular conduit that has an upstream end plate and an inlet for flowing well fluid into an interior of the conduit. A power cable opening extends through the upstream end plate. An electrical submersible pump and motor are in the interior of the conduit. The motor has a motor assembly housing with an upstream end having an electrical insulator opening. An end connection secures the upstream end to an interior side of the upstream end plate with the insulator opening registering with the power cable opening. An insulated electrical connector is mounted in the insulator opening. A motor wire in the motor assembly housing joins to an inner end of the electrical connector. A power conductor extends from exterior of the conduit through the power cable opening and joins to an outer end of the electrical connector.

Abstract: Systems and methods for reducing vibration in an electric motor using rotor bearing assemblies that are positioned within a bore of the stator to support the motor's shaft and rotor sections so that they can rotate within the stator bore. Each rotor bearing assembly includes an outer bearing and an inner bearing sleeve that rotates within the bearing. The bearing is secured so that its rotation within the stator is inhibited, but it can move axially. Each end of the bearing sleeve has a conically tapered contact surface which contacts and secures the corresponding rotor section and centers the rotor section with respect to the axis of rotation of the bearing. The contact surfaces of the rotor sections may be chamfered at an angle complementary to the tapered contact surface of the bearing sleeve to distribute the contact pressure between them over a greater contact surface area.

Abstract: Systems and methods for constructing electric motors in which rotor sections are individually keyed to a rotor shaft such that, in a resting position, the rotor sections are circumferentially shifted (“clocked”) with respect to each to mitigate effects of harmonic feedback, torsional flexibility and the like. In one embodiment, a system includes an electric drive, and an ESP coupled to it by a power cable. The ESP motor has a rotor in which multiple permanent-magnet rotor sections are mounted to a shaft. Within each rotor section, permanent magnets are positioned in two or more axially aligned rows. Adjacent rotor sections are clocked with respect to each other so that, in operation, the rows of permanent magnets in the different rotor sections are positioned to counter the harmonic feedback or to use torsional deflection to equalize torque contributions from the different rotor sections.

Abstract: Systems and methods for connecting power cables to downhole equipment such as ESPs using side-exit (radial) connections. In one embodiment, a system includes an electric drive coupled by a power cable to an ESP. The electric drive is positioned at the surface of a well with the power cable coupled to it. The power cable extends into the well bore and is coupled to the downhole equipment which is positioned in the well bore. The power cable has a connector with a first set of radially oriented terminals (the terminals are perpendicular to the conductors of the power cable). These terminals engage a second set of terminals that are installed in the downhole equipment. The radial orientation of the terminals of the connector and downhole equipment allow the power cable to remain axially oriented, thereby facilitating engagement of the terminals and requiring less annular space in the well bore.