Abstract: An inductor-alternator provides highly efficient conversion between mechanical and electrical energy. The inductor-alternator produces increased output by providing armature coils in a single air gap formed between two halves of a toothed rotor. In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within the rotating rotor. Airgap armature coils are mounted with the field coils to form a stationary assembly that is placed within the single air gap in the rotor so that the changing flux density (due to the rotating teeth) induces an output voltage in the armature coils. The rotor and stationary assembly are mounted in a housing by bolts that may also be used as terminals for the armature coils to reduce assembly complexity and production cost. The combined assembly provides high energy and power density because tip speed of the rotor is maximized and the use of air gaps is minimized.

Abstract: An inductor-alternator provides highly efficient conversion between mechanical and electrical energy. The inductor-alternator produces increased output by providing armature coils in a single air gap formed between two halves of a toothed rotor. In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within the rotating rotor. Airgap armature coils are mounted with the field coils to form a stationary assembly that is placed within the single air gap in the rotor so that the changing flux density (due to the rotating teeth) induces an output voltage in the armature coils. The rotor and stationary assembly are mounted in a housing by bolts that may also be used as terminals for the armature coils to reduce assembly complexity and production cost. The combined assembly provides high energy and power density because tip speed of the rotor is maximized and the use of air gaps is minimized.

Abstract: A replaceable bearing cartridge assembly for use in a flywheel energy system and methods and apparatus for installing and removing the assembly are provided. The assembly includes a hollow bearing cartridge, an annular bearing, and an annular bearing retaining ring. The cartridge has an outer surface which is mounted at a port of a flywheel housing end plate. The annular bearing is mounted in the cartridge and held in place by the annular bearing retaining ring. The retaining ring acts as a backup bushing if the primary bearing fails.

Abstract: An uninterruptible power supply (UPS) provides improved reliability by extending the useful life of a bank of batteries that provide backup power to the UPS in the event of an extended power outage. In the preferred embodiment, battery life is extended by switchably isolating the bank of batteries from the DC buss that is coupled to the critical load. Backup power for short duration outages, on the order of about ten seconds or less, is provided by a flywheel energy storage unit. Once the outage becomes extended, the isolation circuit is triggered to electrically connect the bank of batteries directly to the DC buss. In this manner, the bank of batteries does not experience AC ripple or the common, short duration outages that would otherwise cause the batteries to experience a discharge/recharge cycle.

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: A high inertia inductor-alternator energy storage device provides backup energy in a simple, compact device. The inductor-alternator stores an acceptable level of energy via an improved rotor that provides a high level of rotational inertia. The improved rotor can be manufactured at a reduced cost due to reduced milling requirements. Moreover, the inductor-alternators of the present invention have reduced complexity and increased reliability as a result of the geometry of the improved rotor.

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: A flywheel energy conversion device provides highly efficient conversion between kinetic and electrical energy. The flywheel produces increased output by providing armature coils in an air gap formed about the flywheel (both radial and axial embodiments are described). In preferred embodiments, field coils of a magnetic circuit are energized with DC drive current that creates homopolar flux within a rotating solid rotor having teeth cut from a flat disk. The total reluctance of the magnetic circuit and total flux remain substantially constant as the rotor rotates. The flux may travel radially outward and exit the flat disk through the teeth passing across an armature air gap. Airgap armature coils are preferably utilized in which the changing flux density (due to the rotating teeth) induces an output voltage in the coils.

Abstract: An electrical generator has at least one rotating ring of field magnets which produce a circular array of magnetic fields, and a ring of generator output coils which are in the magnetic fields. The field magnets are permanent magnets. The generator output coils are movable in a displacement path toward and away from a null position at which they are exposed to zero net flux from the magnetic fields. Movement of the coils by an actuator varies the amplitude of the voltage induced in these coils by the rotating field magnets. The actuator is energized by an alternating current to create a mechanical oscillation of the generator output coils in their displacement path. The coils provide a raw amplitude-modulated signal that has a carrier frequency which is a function of the rotational velocity of the field magnets and a modulation frequency that is proportional to the mechanical oscillation of the generator output coils.

Abstract: A brushless generator provides increased output by providing air-core coils (936,956) in place of ferrous coils in regions of the generator which operate at high frequencies. The air-core coils (936,956) enable the generator to rotate at speeds in excess of 24,000 rpm while continuing to operate efficiently because core losses, due to the use of traditional iron cores (e.g., hysteresis and eddy-currents), are virtually eliminated. In preferred embodiments, rotating air-core coils (936) pass through stationary electromagnet fields (920) that induce amplified AC currents in the coils. The AC currents are rectified (950) and fed to rotating electromagnets (922) which create rotating fields. A second set of air-core coils (956) is oriented such that they pass through the rotating fields, which induce an AC voltage which may be used as the output of the generator.

Abstract: An uninterruptible power supply provides improved reliability by supplying temporary standby power to a critical load and startup power to a backup power source from a single energy storage system. In the preferred embodiment, a flywheel energy storage device that produces three-phase AC voltage is used to provide temporary power to a critical load while a backup power supply, such as a diesel generator set (GENSET), is accelerated to full speed. The startup power for the GENSET is also provided from the flywheel energy storage device through a circuit that converts the AC voltage at one level to DC voltage at a lower level (e.g., 12 or 24 volts). Therefore, backup power will be provided from the GENSET unless a catastrophic failure occurs in the GENSET itself.