Abstract: A method and system for magnetically levitating a load is disclosed. One embodiment of the invention is a system for magnetically levitating a load, the system comprising at least two lift generators, each comprising a source of magnetic flux configured to induce a magnetic flux in a rail via a leg on either side of the rail, at least one magnetically permeable beam connecting the lift generators, and control circuitry configured to generate and modulate a magnetic current flux through the crossbeam so as to maintain gaps between the legs and rail, wherein the gaps defined by the legs on either side of the rail are of unequal size.

Abstract: This disclosure describes an ancient mechanical device which has been improved by modern machine tools, lubricants, ball bearings, and now by electromagnetics. A gear reducer/increaser with the use of magnetic bearing technology changes a friction dominated device into an element that can operate efficiently indefinitely in any environment with a range of operation heretofore impossible. Backlash, an inherent weakness of prior precision geared systems is small and controllable. This device can convert linear or rotational motions at specific force or torque levels to larger or smaller displacements with reciprocal changes in force or torque to preserve conservation of energy. It can be constructed in a variety of forms, with circular and concentric form gaining advantages of symmetry mechanically, less stray magnetic flux, and better “copper” utilization electrically.

Abstract: This disclosure describes an electronically commutated linear d.c. motor with an armature and field source fixed relative to each other and a third element on which motor action takes place, consisting of a salient pole structure into which magnetic flux is impressed with no physical contact and little or no reluctance change with axial motion. This machine retains all the virtues of conventional d.c. motors as efficient bilateral mechanical to electrical force transducers, with conventional or ironless armatures and permanent and electromagnet fields. It has a completely passive salient pole element which may be either the stationary or moving part of the motor. This disclosure also illustrates how the newly invented form of linear d.c. motor can be designed in such a way that the magnetic circuit is part of a suspension system. This dual functional use of the magnet and permeable iron minimizes weight and cost.

Abstract: This disclosure describes a new means for suspending and/or centering bodies without physical contact while avoiding some of the characteristic destabilizing forces between ferrous surfaces of prior magnetic bearings. It allows more linear control and produces bidirectional forces while retaining the wearout free and environmental and speed independence obtainable only by magnetic suspension. Single degree of freedom bearings are shown first. Axial, then two types of radial (2 axis) implementations, then four and five axis systems which can be motorized. Finally a “best mode” in which all six degrees of freedom are combined illustrating a uniquely practical configuration is shown. In all cases displacement sensors and conventional electronic control systems are needed and their use is implied since their availability unquestioned as are power supplies.

Abstract: A plurality of identical modules are serially connected together with each module including a base plate and a top plate interconnected by a universal joint assembly so that the top plate is adapted to pivotally nutate around the base plate to describe a cone in space. An array of twenty-four electromagnets, sequentially energized in sets of three, are arranged in a ring around the periphery of the base plate. Selective energization of the eight sets of electromagnets causes the rim of the top plate to be magnetically attracted to the energized electromagnets. The tilt of the top pivot plate is detected and controlled over a range of 360.degree., thus permitting a series string of modules to assume any desired elongated configuration.

Abstract: A brushless DC motor is disclosed wherein armature forces can be produced and controlled as both radial forces and as torque couples. A structure is described in which the normal radial destabilizing forces due to the high levels of magnetic flux linking the stator and rotor are reduced and the force gradient is moderated. This is accomplished by locating the rotor between two concentric stator coil assemblies either of which may be used for bearing or torquing to join the rotor magnets via magnetically "soft" iron, thereby reducing the rotor mass and inertia with the consequent improvement in dynamic performance. Since the forces on the rotor are the sum of the forces produced by each individual stator coil, it is possible to combine groups of stator coils in various ways and independently control them to achieve the dual purpose.

Abstract: A three axis attitude control system for an orbiting body, such as a spacecraft, comprises a motor driven flywheel supported by a torque producing active magnetic bearing. Free rotation of the flywheel is provided about its central axis and together with limited angular torsional deflections of the flywheel about two orthogonal axes which are perpendicular to the central axis. The motor comprises an electronically commutated DC motor, while the magnetic bearing comprises a radially servoed permanent magnet biased magnetic bearing capable of producing cross-axis torques on the flywheel. Three body attitude sensors for pitch, yaw and roll generate respective command signals along three mutually orthogonal axes (x, y, z) which are coupled to circuit means for energizing a set of control coils for producing torques about two of the axes (x and y) and speed control of the flywheel about the third (z) axis.

Abstract: A single degree of freedom suspension element exhibiting substantially zero natural frequency of vibration with electronically controllable response comprising the combination of a mechanical spring and an "electromagnetic spring" which axially supports a mass located on a base. The electromagnetic spring includes two identical and symmetrical permanent magnet circuits having adjacent like-polarity poles joined by a permeable magnetic shunt member. The magnet circuits include an air gap between pairs of pole faces and within which prominences of a magnetically permeable armature extend therein and partially short each of the air gaps. An electromagnetic coil is located inwardly of the magnetic shunt between the magnetic circuits and encircles the armature between the prominences. The mechanical spring is coupled to the armature and acts to center the prominences in the air gap.

Abstract: A magnetic bearing including a circular stator member having a plurality of circumferential pole faces and a suspended annular ring member with corresponding number of inward facing circumferential pole faces separated by respective air gaps. A source of DC magnetic flux circulates flux between the circumferential pole faces of the stator and the ring to provide axial stability along a central longitudinal axis. Flux coil means are included on the stator member for providing variable flux density along predetermined radial paths to provide active radial stabilization. Additionally, flux coil means are included on the stator to actively modulate the magnitude of the magnetic forces as well as their direction of differential flux control involving the DC magnetic flux to produce torquing moments about a pair of mutually orthogonal axes which are perpendicular to the central axis.

Abstract: A vibration free fluid compressor particularly adapted for Stirling cycle cryogenic refrigeration apparatus comprising a pair of identical opposing ferromagnetic pistons (10, 12) located in a housing (22) and between a gas spring including a sealed volume (52, 54, 60) of a working fluid such as gas under pressure. The gas compresses and expands in accordance with movement of the pistons (10, 12) to generate a compression wave which can be vented out to other apparatus, for example, a displacer unit in a Stirling cycle engine. The pistons (10, 12) are urged outwardly due to the pressure of the gas; however, a fixed electromagnetic coil assembly (56), located in the housing adjacent the pistons, is periodically energized to produce a magnetic field which interlinks the pistons (10, 12) in such a fashion that the pistons are mutually attracted to one another.

Abstract: A counter-rotating machine, such as a positive displacement pump having a pair of meshed, non-contacting helical screws (10,12), subjects its rotating members to axial and radial thrust forces when used for such purposes as compression of liquid or gaseous phase fluids while transporting them through a pump cavity (11,13). Each helical screw (10,12) has a shaft (17,17') which is actively suspended at opposite ends (11a,11b) of the pump cavity by a servo-controlled magnetic bearing assembly (19) and a servo-controlled rotary drive motor (20). Both bearing assemblies and drive motors are mounted on the outside of the pump cavity (11,13). Opto-electric angular position sensors (250) provide synchronization between radial orientation of the drive motors. The bearing assemblies and drive motors conjugately provide axial stabilization and radial centering of the helical screws during volumetric compression of aspirated liquid or gaseous phase fluids.

Abstract: A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications comprised of a compressor section (10) centrally aligned end to end with an expansion section (12) and respectively including a reciprocating compressor piston (14) and displacer (16) radially suspended in interconnecting cylindrical housings (18, 20) by active magnetic bearings (26, 28, 30, 32) and having adjacent reduced clearance regions (82, 84, 108) so as to be in non-contacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston (14) and displacer (16) are reciprocated in their housings (18, 20) by linear drive motors (48, 52) to vary the volume of respectively adjacent compression and expansion spaces (44, 46) which contain a gaseous working fluid and a thermal regenerator (95) to effect Stirling cycle cryogenic cooling.

Abstract: A linear magnetic bearing includes a stator member (16) stationary relative to x, y and z axes and having a longitudinal axis on the z axis as well as a member (15) longitudinally translatable relative to said axes. The translatable member (15) is controlled to have a longitudinal axis coincident with the z axis. Permanent magnets (36 and 37) on one of the members positions the translatable member (15) in a plane defined by the x-y axes relative to the stationary member (16). The position of the translatable member (15) is sensed by sensors (41 and 42) relative to the stationary member (16) in the plane defined by the x-y axes. Electro-magnets (38 and 39) on one member (23) responds to the sensor (41 and 42) to center the longitudinal axis of the translatable member (15) on the z axis. First low reluctance magnetic flux paths for the permanent magnets (36 and 37) exist through both of the members and a radial air gap (32, 33, 34 and 35) between the members.

Abstract: A magnetic bearing assembly (10) has an intermediate rotatable section (33) having an outer cylindrical member (30) coaxially suspended by a torsion wire (72) around an axially polarized cylindrical magnet (32). Axial alignment between the pole faces (40-43) of the intermediate section (33) and end surfaces (50-53) of opposed end bells (20, 22) provides a path of least reluctance across intervening air gaps (60-63) for the magnetic flux emanating from magnet (32). Radial dislocation increases the reluctance and creates a radial restoring force. Substitution of radially polarized magnets 107 fixed to a magnetically permeable cylinder (32') and insertion of pairs of armature coil windings (109-112) between the cylinder pair (33') provides an integral magnetic bearing and torsion motor (100) able to provide arcuately limited rotational drive.

Abstract: A transformer (20) for coupling AC electrical energy from a stationary element (22) to a rotating element (24) without the use of sliding contacts. The transformer (20) is of the rotary type and includes a ferrite core (39) and two primary windings (70 and 72) which are stationary with respect to a secondary winding (88) which rotates within an annular cavity (48) adjacent an axial bore (58) in the core. The core (39) is comprised of two cup type core halves (40 and 42). Electrical connection to the secondary winding (88) is made through a split bobbin assembly (89) which couples to a coaxial shaft assembly (59) located in the axial bore (58). The electrical coupling to the coaxial shaft assembly is made through a continuous transverse channel (68) connecting the axial bore (58) with the annular cavity (48). The transverse channel (68) forms a single air gap; however, it is not open directly to free space but is shielded by the magnetic permeable material of the core halves (40 and 42).

Abstract: A linear magnetic motor/generator (10) is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator (10) includes an axially movable actuator mechanism (12). A permanent magnet mechanism (14) defines a first magnetic flux path (16) which passes through a first end portion (18) of actuator mechanism (12). Another permanent magnet mechanism (20) defines a second magnetic flux path (22) which passes through a second end portion (24) of actuator mechanism (12). A drive coil (26) defines a third magnetic flux path (28) passing through a third central portion (30) of actuator mechanism (12). Drive coil (26) selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux paths (16) and (22), respectively, for supplying an axial force to the actuator mechanism (12).

Abstract: An energy storage device comprises a flywheel rotor in the form of a spokeless ring of filamentary, composite material rotating around a ring-shaped stator. Along the inner rim of the rotor, there is a layer of magnetically soft iron that forms homopolar, salient pole pairs. An ironless armature winding mounted on the stator extends into an air gap formed between the pole pairs. To bring the rotor up to speed, alternating current is supplied to the armature winding using electronic commutation. The armature current interacts with flux in the air gap to create a force acting to rotate the rotor. During coast down, current may be tapped from the rotor using commutation diodes. The rotor and stator are maintained in axial alignment to each other by magnetic flux produced by a permanent magnet in the stator. An electromagnet incorporated in the stator modulates permanent magnet flux to compensate for any eccentricity between the stator and the rotor that may develop during rotation.

Abstract: A three phase decoder for DC motors is disclosed which employs an extremely simple six transistor circuit to derive six properly phased output signals for fullwave operation of DC motors. Six decoding transistors are coupled at their base-emitter junctions across a resistor network arranged in a delta configuration. Each point of the delta configuration is coupled to one of three position sensors which sense the rotational position of the motor. A second embodiment of the invention is disclosed in which photo-optical isolators are used in place of the decoding transistors.

Abstract: A single magnetic, radial bearing having a disc with an axis coincident with the bearing or shaft axis, the bearing passively supporting an annulus which forms a radial gap between its inner circumferential edge and the circumferential edge of the disc. The disc has a relatively large diameter compared to its length along the axis.