Abstract: A drive support unit of a turbo compressor includes at least one bearingless motor. The at least one bearingless motor includes a rotor-stator pair constituted by a rotor and a stator, and is configured to rotationally drive a drive shaft and to support a radial load of the drive shaft in a contactless manner. Accordingly, it is possible to provide a turbo compressor to which a bearingless motor is applied.

Abstract: An electric motor system includes a drive shaft, a first electric motor, a second electric motor, a first inverter, a second inverter and a control unit. The drive shaft is rotatable around an axis. The first electric motor and the second electric motor rotate the drive shaft. The first inverter supplies power in order to generate a torque to the first electric motor. The second inverter supplies power in order to generate a torque to the second electric motor. The control unit controls the first inverter and the second inverter. The controller is configured to be able to change a ratio between an output torque of the first electric motor and an output torque of the second electric motor.

Abstract: An electric motor includes a rotor and a stator having a stator core, a suspension winding group, and an armature winding group. The stator core includes a back yoke and a plurality of teeth. The suspension winding group includes a plurality of suspension windings wound on the teeth. The suspension windings generate an electromagnetic force that supports the rotor in a non-contact manner, and generate a magnetic pole inside the stator. The armature winding group includes a plurality of armature windings wound on the teeth. The armature windings generate an electromagnetic force that rotationally drives the rotor, and generate a magnetic pole inside the stator. One of the suspension or armature winding groups includes a plurality of series winding sets with a plurality of series connected windings of a same phase. Each series winding set is connected in parallel with an other one of the series winding sets.

Abstract: An electric motor system includes a drive shaft configured to rotationally drive a load, a bearingless motor and a radial magnetic bearing arranged side by side in an axial direction of the drive shaft, and a thrust magnetic bearing disposed between the bearingless motor and the radial magnetic bearing. A radial load on the drive shaft is supported in a non-contact manner by the bearingless motor and the radial magnetic bearing.

Abstract: The stator includes a stator core, a support electric wire formed by one or more conductive wires, and a drive electric wire formed by one or more conductive wires. The stator core includes an annular shaped back yoke and a plurality of teeth on an inner periphery of the back yoke. The support electric wire is disposed so as to pass through a plurality of slots respectively formed between the teeth, and forms a winding portion that generates an electromagnetic force for supporting the rotor in a non-contact manner by being energized. The drive electric wire is disposed so as to pass through the plurality of slots, and forms a winding portion that generates an electromagnetic force for rotating the rotor by being energized. A cross-sectional area per conductive wire of the support electric wire differs from a cross-sectional area per conductive wire of the drive electric wire.

Abstract: An electric motor system includes a drive shaft, a first electric motor, a second electric motor, a first inverter, a second inverter and a control unit. The drive shaft is rotatable around an axis. The first electric motor and the second electric motor rotate the drive shaft. The first inverter supplies power in order to generate a torque to the first electric motor. The second inverter supplies power in order to generate a torque to the second electric motor. The control unit controls the first inverter and the second inverter. The controller is configured to be able to change a ratio between an output torque of the first electric motor and an output torque of the second electric motor.

Abstract: A rotor includes a rotor core having a plurality of magnetic poles. At least one magnetic pole includes a first magnetic pole having three or more circumferentially arranged magnet holes, and a plurality of permanent magnets housed corresponding magnet holes. A portion of the rotor core between adjacent magnet holes has a radially extending region. A maximum radial dimension of each magnet hole is greater than a minimum radial dimension of a portion of the rotor core between a magnet hole radially outer surface and a rotor core outer peripheral surface. The first magnetic pole has a smaller amount of harmonic components in a radial flux density distribution on the rotor core outer peripheral surface, compared to a magnetic pole having a plurality of magnet holes arranged at equal circumferential intervals and a plurality of permanent magnets having substantially the same magnetic flux and number.

Abstract: A hydroelectric generation system includes a fluid machine disposed in a penstock or channel, a generator driven by the fluid machine, and a control unit configured to generate a predetermined torque in the generator. Fluid flows through the penstock or channel. The penstock or channel has a main path in which the fluid machine is disposed, and a detour disposed in parallel with the main path. The detour includes an on-off valve. The on-off valve is opened when not electrified, and closed when electrified.

Abstract: An electric motor system includes a drive shaft that rotationally drives a load, a bearingless motor, a power source unit, and a control unit. The bearingless motor includes a rotor and a stator having armature and support windings. The bearingless motor rotationally drives the drive shaft and supports a radial load of the drive shaft in a contactless manner. The power source unit applies a voltage to the armature and support windings. The control unit controls the power source unit so that a radial support force that is a sum of a radial support force caused by a support current and a radial support force caused by both the support current and an armature current is output, and so that one of an armature voltage across the armature winding and the support current is increased and the other of the armature voltage and the support current is decreased.

Abstract: A drive support unit of a turbo compressor includes at least one bearingless motor. The at least one bearingless motor includes a rotor-stator pair constituted by a rotor and a stator, and is configured to rotationally drive a drive shaft and to support a radial load of the drive shaft in a contactless manner. Accordingly, it is possible to provide a turbo compressor to which a bearingless motor is applied.

Abstract: An electric motor system includes a drive shaft that rotationally drives a load, a bearingless motor, a power source unit, and a control unit. The bearingless motor includes a rotor and a stator having armature and support windings. The bearingless motor rotationally drives the drive shaft and supports a radial load of the drive shaft in a contactless manner. The power source unit applies a voltage to the armature and support windings. The control unit controls the power source unit so that a radial support force that is a sum of a radial support force caused by a support current and a radial support force caused by both the support current and an armature current is output, and so that one of an armature voltage across the armature winding and the support current is increased and the other of the armature voltage and the support current is decreased.

Abstract: An electric motor system includes a drive shaft that rotationally drives a load, a bearingless motor, a power source unit, and a control unit. The bearingless motor includes a rotor and a stator having armature and support windings. The bearingless motor rotationally drives the drive shaft and supports a radial load of the drive shaft in a contactless manner. The power source unit applies a voltage to the armature and support windings. The control unit controls the power source unit so that a radial support force that is a sum of a radial support force caused by a support current and a radial support force caused by both the support current and an armature current is output, and so that one of an armature voltage across the armature winding and the support current is increased and the other of the armature voltage and the support current is decreased.

Abstract: The stator includes a stator core, a support electric wire formed by one or more conductive wires, and a drive electric wire formed by one or more conductive wires. The stator core includes an annular shaped back yoke and a plurality of teeth on an inner periphery of the back yoke. The support electric wire is disposed so as to pass through a plurality of slots respectively formed between the teeth, and forms a winding portion that generates an electromagnetic force for supporting the rotor in a non-contact manner by being energized. The drive electric wire is disposed so as to pass through the plurality of slots, and forms a winding portion that generates an electromagnetic force for rotating the rotor by being energized. A cross-sectional area per conductive wire of the support electric wire differs from a cross-sectional area per conductive wire of the drive electric wire.

Abstract: A hydroelectric generation system includes a fluid machine disposed in a penstock or channel, a generator driven by the fluid machine, and a control unit configured to generate a predetermined torque in the generator. Fluid flows through the penstock or channel. The penstock or channel has a main path in which the fluid machine is disposed, and a detour disposed in parallel with the main path. The detour includes an on-off valve. The on-off valve is opened when not electrified, and closed when electrified.

Abstract: A magnetic bearing which would reduce a leakage magnetic flux to be generated between teeth is provided. A predetermined one of its teeth (24) is configured so that a pitch (P1) between the predetermined tooth (24) and one of two adjacent teeth (24) that are located on clockwise and counterclockwise sides thereof in the circumferential direction is broader than a pitch (P2) between the predetermined tooth (24) and the other tooth (24) and that a magnetic flux flows in the same radial direction through the predetermined tooth (24) and the tooth (24) spaced from the predetermined tooth (24) by the narrower pitch (P1) but flows in two different radial directions through the predetermined tooth (24) and the tooth (24) spaced from the predetermined tooth (24) by the broader pitch (P2).

Abstract: A magnetic bearing body supports a rotating shaft using a combined electromagnetic force of a pair of control electromagnets without contact. A controller detects a control index value based on a first coil current passed through a coil of a first control electromagnet of the pair of control electromagnets which generates an electromagnetic force in the same direction as that of a load exerted on the rotating shaft, the control index value being an index of the degree of margin for error in control depending on a value of the first coil current. And the controller controls a middle value of a pair of coil currents passed through the respective corresponding coils of the pair of control electromagnets so that the control index value approaches a predetermined target index value.

Abstract: A stator is provided which exerts a combined electromagnetic force of a plurality of electromagnets on a drive shaft having a fluctuating load. A controller is provided which controls a current difference between a first coil current passed through a coil of the electromagnet generating an electromagnetic force in a direction opposite to that of the load and a second coil current passed through a coil of the electromagnet generating an electromagnetic force in the same direction as that of the load to perform a position control on the drive shaft. The controller adjusts the second coil current to reduce an average value of the second coil current.

Abstract: A magnetic bearing which would reduce a leakage magnetic flux to be generated between teeth is provided. A predetermined one of its teeth (24) is configured so that a pitch (P1) between the predetermined tooth (24) and one of two adjacent teeth (24) that are located on clockwise and counterclockwise sides thereof in the circumferential direction is broader than a pitch (P2) between the predetermined tooth (24) and the other tooth (24) and that a magnetic flux flows in the same radial direction through the predetermined tooth (24) and the tooth (24) spaced from the predetermined tooth (24) by the narrower pitch (P1) but flows in two different radial directions through the predetermined tooth (24) and the tooth (24) spaced from the predetermined tooth (24) by the broader pitch (P2).

Abstract: In a fuel injection valve, it is intended to enhance valve-closing responsivity while maintaining durability (anti wear property) of a collision portion between a stationary core and a movable core and valve-opening responsivity. An annular end face 106A of the movable core 106 in the fuel injection valve is provided with a collision portion 106C that collides to a stationary core 107 when the movable core is magnetically attracted toward the stationary core side and a non-collision portion that keeps a fluid gap between both cores at an area of an outer side or an inner side from the collision portion. The annular end faces of the stationary core and the movable core are coated with platings 30, 31 having anti wear property, and at least one of the platings of the stationary core and the movable core is formed in such a manner that the thickness thereof at the collision portion 106C is to be thicker and the thickness thereof at the non-collision portion is to be thinner.

Abstract: A magnetic bearing body supports a rotating shaft using a combined electromagnetic force of a pair of control electromagnets without contact. A controller detects a control index value based on a first coil current passed through a coil of a first control electromagnet of the pair of control electromagnets which generates an electromagnetic force in the same direction as that of a load exerted on the rotating shaft, the control index value being an index of the degree of margin for error in control depending on a value of the first coil current. And the controller controls a middle value of a pair of coil currents passed through the respective corresponding coils of the pair of control electromagnets so that the control index value approaches a predetermined target index value.