Abstract:
A corrugated pallet folded together from two planar blanks, including a pallet top that supports a load above a floor, and a pallet bottom that rests on the floor. Each pallet top and pallet bottom has multiple double thickness interior support ribs folded vertically from the plane of the pallet top and bottom. Ribs from the pallet top intersect with ribs from the pallet bottom perpendicularly and support the pallet top on the pallet bottom. Multiple mechanical vertical locks hold the pallet top in vertically spaced relation with the pallet bottom with middle straps folded vertically from the pallet top and/or pallet bottom into contact with interior surfaces of the pallet and lock directly into sides of the interior support ribs at positions intermediate the pallet top and bottom. Reinforcement tubes are provided over intersections of double thickness ribs at the corners of the pallet while folded doubled thickness ribs provide compression support near the center.
Abstract:
A process for assembly of a brushless air core motor-generator includes assembling a rotor formed from two spaced apart rotor portions having magnetic poles that drive magnetic flux circumferentially through the rotor portions and back and forth across an armature airgap between the rotor portions. An air core armature is made by coating a nonmagnetic armature form with a tacky adhesive layer, and winding armature windings in a winding pattern onto the form with a winding head, using wire comprised of bundled multiple individually insulated conductor strands that are electrically connected in parallel but are electrically insulated from each other along their lengths where located inside the magnetic flux in the armature airgap. The armature windings are adhered to the nonmagnetic form simultaneously as the winding head traverses the winding pattern while applying pressure to the wire against the tacky adhesive, so tack of the tacky adhesive layer holds the wire to the armature form during the winding process, in the winding pattern later required for magnetic torque production. The air core armature is inserted into the armature airgap and mounted to a stator of the motor-generator for production of magnetically induced torque between the rotor and the stator.
Abstract:
A brushless permanent magnet motor has a rotor constructed of spaced ferromagnetic backirons and a circumferential array of alternating polarity magnetic poles that drive magnetic flux back and forth across an armature air gap between the backirons. A stator includes an air core armature in the air gap with three-phase windings. An inverter includes a pulse-modulated semiconductor H-bridge that switches and regulates power to the three-phase windings to drive the rotor. Harmonic losses in the motor caused by ripple currents generated by the higher pulse switching frequency in electronic variable speed drives, due to the inherently lower inductance of air core motors, are substantially reduced by adding serial inductance between the motor and drive. The H-bridge is serially electrically connected to the three-phase armature windings through three inductors that employ a low cost powder core. Each of the inductors provides an inductance that is greater than twice the value of the leg inductance of the three-phase windings.
Abstract:
A high-speed steel flywheel for a flywheel uninterruptible power is constructed by stacking several unpierced steel discs together. Each disc is heat treated prior to assembly. Thin axial thickness of each disc enables complete rapid quenching to attain a fully hardened condition and development of high tensile strength. The individual discs are machined or ground to shape and assembled to form an axially thicker flywheel capable of storing several kilowatts of energy or more. The discs are attached together by welding, brazing, soldiering, bonding or an interference assembly. The stacked disc configuration minimizes chances of catastrophic failure of the flywheel due to initiation of a crack in a single disc by restricting axial crack propagation to that single disc, and supporting the cracked disc by one or more adjacent discs until the flywheel can be safely decelerated.
Abstract:
A wind turbine for generating electrical power from wind energy includes a turbine rotor mounted for rotation in wind, and having multiple blades for converting energy in the wind into rotational energy. A generator is coupled with said turbine rotor such that said turbine rotor drives said generator. The generator has a stationary air core armature that is located in a magnetic airgap between two generator rotor portions. The generator rotor portions have circumferential arrays of multiple alternating polarity permanent magnets attached to ferromagnetic back irons such that the permanent magnets drive magnetic flux back and forth between each rotor portion and through the stationary air core armature. The stationary air core armature has multiple phase windings of multiple individually insulated strand conductor wire that is wound with two separate portions including an active length portion and an end turn portion. The end turn portion is located outside the magnetic airgap and traverses predominately circumferentially, and the active length portion is located in the magnetic airgap and traverses predominately non-circumferentially and perpendicular to the direction of the magnetic airgap. The end turn portion has a thickness that is greater than the thickness of said active length portion in the direction of said magnetic airgap. AC voltage is induced in the multiple phase windings as the turbine rotor rotates.
Abstract:
An inductor alternator flywheel system, for converting between electrical and kinetic energy, includes an annular steel flywheel mounted on bearings for rotation about an axis. The flywheel has an inwardly facing radial surface forming multiple protrusions or teeth extending radially inwardly. A yoke has a field coil for producing homopolar flux which creates magnetic poles in the teeth. A cylinder constructed of substantially high permeability material, and having an outer radial surface, is mounted concentrically in the bore of the annular flywheel and is spaced apart radially from the teeth such that an armature air gap is formed between the teeth and the outer surface of the cylinder. A ring of armature coils is mounted within the air gap such that the flux induces an alternating voltage in the armature coils when the rotor rotates about its axis. A field controller provides field power at a level to the field coil when the flywheel is rotating at normal fill operating speed such that the generator provides full output power under full load to the output at the instant of disruption in primary power. The field controller increases the field power during a continuous disruption of primary power to maintain a substantially constant output voltage at the output as the generator speed decreases.
Abstract:
A composite flywheel rotor includes an annular rim mounted on a hub for high speed rotation in an evacuated flywheel enclosure. A smooth epoxy layer is applied to the rim and is cleaned or maintained clean in preparation for a metal coating on the rim. The rim may be baked in a vacuum furnace to drive off the volitiles and water vapor, and a thin metal coating is applied over the entire rim to retard outgassing from the resin in the flywheel composite rim. The metal coating on flywheel rim is preferably aluminum because aluminum adheres well to epoxy and is economical. The metal coating is deposited on the flywheel rim by physical vapor deposition and may be built up after an initial PVD coating by electroplating. A tough protective polymer is applied over the metal coating to protect metal coating from mechanical damage during handling.
Abstract:
A flywheel energy storage system includes an energy storage flywheel supported for rotation about a substantially vertical axis on a combination bearing system comprised of a mechanical and a magnetic bearing. A motor and generator accelerates and decelerates the flywheel for storing and retrieving energy. The mechanical bearing is located at one axial end of the flywheel and provides axial downward force to the flywheel and is connected to the mechanical rolling element bearing using a low radial stiffness connecting element. The magnetic bearing is located at the axial end of the flywheel opposite the end with the mechanical bearing and provides axial upward force to support the weight of the flywheel, and also provides passive magnetic radial centering force to the flywheel.
Abstract:
An active magnetic thrust bearing, acting on only a single axial side of a rotor, while also having an efficient permanent magnet bias for linearized and highly amplified control, uses two concentric ring poles that axially face a ferromagnetic axial surface of the rotor, creating two annular axial air gaps. A permanent magnet in the stator drives a bias flux through a first path including two radially spaced concentric ring poles and their air gaps, and an annular region of the rotor axially aligned between the two ring poles. The permanent magnet also drives flux through a second high-reluctance flux path in the stator, by-passing the rotor. An electromagnetic coil in the stator drives a control flux in a circuit including the second path, both ring poles and axial air gaps, and the shunt. The bias and control fluxes are therefore superposed in the axial air gaps for amplified response.
Abstract:
A combination mechanical and magnetic support system for a flywheel power supply for storing and retrieving energy in which said power supply includes a flywheel that spins about an axis of rotation inside an evacuated chamber, and an attached motor/generator for accelerating and decelerating the flywheel for storing and retrieving the energy. One or more rolling element bearings and at least one magnetic bearing are mounted in bearing housings attached to the chamber for providing radial and axial support for the flywheel in the chamber. A wire metal mesh spring damper between portions of the rolling element bearings and the bearing housings provide both radial damping and radial centering stiffness to the wheel. The support system has a radial stiffness that allows a cylindrical rigid body resonance of said flywheel to occur at a speed less 30% of the normal operating speed. The magnetic bearings support at least than 80% of the weight of the flywheel, thereby substantially extending the life the of the rolling element bearings.