A positive-side heat sink and a negative-side heat sink are both disposed on a generally flat plane perpendicularly intersecting a shaft, the longitudinal direction of the positive-side diodes secured to the radially inner positive-side heat sink being disposed along the radial direction of the positive-side heat sink, and the longitudinal direction of the negative-side diodes secured to the radially outer negative-side heat sink being disposed along the circumferential direction of the negative...

A bearing design for a rotatable assembly includes two freely rotating balls mounted on the axis of rotation of the assembly and axially separated, one near each axial end of the assembly. Each ball is confined by a moving concave (preferably conical or frustro-conical) bearing surface of the rotatable assembly and a corresponding fixed concave bearing surface of a mounting attached to a frame, housing, or similar non-rotating structure. One of the fixed mountings is preferably attached to a com...

An electrostatic actuator having two-dimensional in-plane motion of a monolithic element suspended by flexures which is unstable in the open-loop and uses feedback control to operate. By adding a common bias voltage to each of the stator electrodes when the translator and stator are in the unstable equilibrium position, repulsion can be reduced to zero while the in-plane force remains in unstable equilibrium. Stabilizing the in-plane force at the unstable equilibrium position is achieved by shif...

An electromechanical machine includes a stator fixed with respect to a housing structure and a rotor fixed with respect to a driven shaft. The stator includes a magnetically permeable core having a plurality of parallel winding slots containing conductive windings. Coilheads are located at opposite axial ends of the magnetically permeable core where the windings turn to extend down a parallel winding slot. The motor is equipped with an electrostatic shield arrangement to reduce capacitive coupli...

A spindle motor includes a housing, a rotor hub section arranged rotatably with respect to the housing, a sleeve section, a shaft fit rotatably in the sleeve section, and a thrust plate mounted to the sleeve section opposite to an end surface of the shaft. A thrust dynamic pressure bearing has a dynamic pressure bearing groove formed on the thrust plate, the thrust dynamic pressure bearing including lubricating oil at a relative slide interface between the thrust plate and the end surface of the...

In a stepping motor, stator yokes have a plurality of comb-tooth-shaped magnetic poles 5b, 6b, 7b and 8b in such a manner that the comb-tooth-shaped magnetic poles are opposed to each other coaxially to a rotor portion made from a permanent magnet magnetized to have multiple magnetic poles, and an excitation coil is fitted on the external circumference of the stator yokes and the excitation coil and the stator yokes are surrounded by a frame yoke. Each of the yokes is formed of an Fe--Cr alloy h...

A field replaceable air-gap cartridge armature device for use in rotating electric machines is presented. The cartridge armature includes a plurality of bent-shaped air-gap windings rigidly arranged in a circular fashion to form an inner rim, an outer rim and an active section. The inner and outer rims are formed by end turn sections that are bent toward and away, respectively, from the center of the cartridge device. The windings may be generally arranged into a Z-shaped cross-section that is e...

A media ejection system includes a peripheral unit having a housing, an ejection mechanism, and a memory wire coupled to the ejection mechanism. The system further includes a digital processor for issuing ejection commands, and a controller responsive to the ejection command for controlling a current flow through the memory wire. When sufficient current flows through the memory wire, it contracts to activate the ejection mechanism, thereby ejecting a removable medium (such a PCMCIA card) from th...

A DC driven fan with blades made of magnetized material and permanently magnetized in the radial direction and cooperating with a plurality of electromagnetic stator coils mounted external to the outer fan edges. Adjacent blades have alternate N-S, S-N radial magnetic orientations. In one embodiment, the blades are mounted in a non-ferrous hub and in an alternate embodiment they are mounted in a ferrous hub so that adjacent blades function like a U or V-shaped magnet. Blades can be made of magne...

A motor with small ripple and capable of high-speed rotation includes six stator poles having widths of about 60 degrees, which is less than 60 degrees when converted to rotor rotational angle. Excitation windings (HA3, HA4, and so forth) wound around the stator poles are connected in series with adjacent excitation winding connected in reverse series. Torque windings (HA1, HA2, and so forth) wound around the stator poles have three phases, where each phase winding comprises a pair on opposite s...