An electric machine comprising a first carrier having an array of electromagnetic elements and a second carrier having electromagnetic elements defining magnetic poles, the second carrier being arranged to move relative to the first carrier. An airgap is provided between the first carrier and the second carrier. The electromagnetic elements of the first carrier include posts, with slots between the posts, one or more electric conductors in each slot, the posts of the first carrier having a post height in mm. The first carrier and the second carrier together define a size of the electric machine. The magnetic poles having a pole pitch in mm. The size of the motor, pole pitch and post height are selected to fall within a region in a space defined by size, pole pitch and post height that provides a benefit in terms of force or torque per weight per excitation level.

A rotor for an electric machine having posts extending partially or completely between end irons. Each end iron is formed of a single piece of magnetic material with the posts extending from it, including the other end iron where the posts extend completely between them. Magnets are arranged between the posts with poles facing the posts to concentrate flux. In order to prevent too much of the flux from being drawn into flux paths through the end irons, the total magnetic flux is made to exceed a saturation flux of at least a portion of the flux path. This may be achieved by using interdigitated posts extending only partially between the end irons to provide gaps in the flux path, by providing flux resistors in the end irons to reduce a saturation flux below the total flux, or by using high aspect ratio magnets or posts so that the magnetic flux exceeds a saturation flux of the posts or end irons.

A system for transferring electric power is provided. A power supply conductor conducts a power supply current that generates a first resultant magnetic field. An electric motor has a power input terminal connected to the power supply conductor and a movable output component. A generator has a movable input component connected to the movable output component such that the movable output component causes movement of the movable input component. The generator converts the movement of the movable input component into a power output current to the power output terminal that generates a second resultant magnetic field. A plurality of field line guides are positioned for field lines of the second resultant magnetic field to couple to the plurality of field line guides and are formed to guide the field lines into a helical shape.

A system for transferring electric power is provided. A power supply conductor conducts a power supply current that generates a first resultant magnetic field. An electric motor has a power input terminal connected to the power supply conductor and a movable output component. A generator has a movable input component connected to the movable output component such that the movable output component causes movement of the movable input component. The generator converts the movement of the movable input component into a power output current to the power output terminal that generates a second resultant magnetic field. A plurality of field line guides are positioned for field lines of the second resultant magnetic field to couple to the plurality of field line guides and are formed to guide the field lines into a helical shape.

A motor-actuator device using a PDL trap system is provided. In one aspect, a motor-actuator device includes: a PDL trap having a pair of diametric magnets, and a levitated diamagnetic rotor in between the diametric magnets, wherein at least a portion of the diamagnetic rotor has a rectangular shape; and an electrode shell having at least one pair of semicircular electrodes which surround, but are in a non-contact position with the levitated diamagnetic rotor and each other. A system including the motor-actuator device and an electrode driver circuit is also provided, as is a method of operating the motor-actuator device.

An apparatus for rotating a shaft by using an electromagnet is provided. Permanent magnets are placed around a shaft to rotate with the shaft, and an electromagnet is placed outside the circumference of the permanent magnets, and a device for activating electromagnet is placed. Two secondary cell batteries are used to activate the electromagnet and the electromagnet makes the permanent magnets rotate. The secondary cell batteries are charged using back-emf which occurs in the electromagnet. Coils are placed around the circumference of the permanent magnets and the rotating permanent magnets generate electricity to the coils.

An electric motor has a first carrier having an array of electromagnetic elements and a second carrier having electromagnetic elements defining magnetic poles. The first and second carriers each define an axis. An airgap is formed between the first and second carriers when in an operational position. An inner thrust bearing connects the first and second carriers and is arranged to allow relative rotary motion of the carriers. An outer thrust bearing connects the first and second carriers and is arranged to allow relative rotary motion of the carriers. The electromagnetic elements of each of the first and second carriers are arranged radially inward of the outer thrust bearing and radially outward of the inner thrust bearing. The inner thrust bearing and the outer thrust bearing are arranged to maintain the airgap against a magnetic attraction of the electromagnetic elements of the first and second carriers.

An electric motor has a first carrier having an array of electromagnetic elements and a second carrier having electromagnetic elements defining magnetic poles. The first and second carriers each define an axis. An airgap is formed between the first and second carriers when in an operational position. An inner thrust bearing connects the first and second carriers and is arranged to allow relative rotary motion of the carriers. An outer thrust bearing connects the first and second carriers and is arranged to allow relative rotary motion of the carriers. The electromagnetic elements of each of the first and second carriers are arranged radially inward of the outer thrust bearing and radially outward of the inner thrust bearing. The inner thrust bearing and the outer thrust bearing are arranged to maintain the airgap against a magnetic attraction of the electromagnetic elements of the first and second carriers.

A compact three-phase permanent magnet rotary machine having minimal reluctance torque and electromagnetic torque ripple, and maximum energy efficiency and starting torque per unit volume of winding, comprises an armature having 3(2n+1) ferromagnetic poles and slots, where n is an integer of 1 or more, and a permanent magnet assembly having either 2, 4 or 6 permanent magnet poles. Each of the three phases of the winding comprises multiple coils, each wound about a respective ferromagnetic pole and occupying a pair of slots located immediately on each side of a respective pole. The coils of a particular phase are located within a sector of the circular array of ferromagnetic poles encompassing 2n+1 poles.

In a hydraulic control device, when the rotational speed of an electric motor is an appropriate rotational speed, a first spool is in a first position, in which communication between a sixth port and a second port is blocked. When the rotational speed of the electric motor exceeds the appropriate rotational speed, the first spool is in a second position, in which the sixth port and the second port are placed in communication.