1053 results about "Rotor magnets" patented technology

A motor providing unidirectional rotational motive power is provided. The motor has a generally circular stator with a stator axis, an outer surface, and a circumferential line of demarcation at about a midpoint of the outer surface. The motor also includes one or more stator magnets attached to the outer surface of the stator. The stator magnets are arranged in a generally circular arrangement about the stator axis and generate a first magnetic field. An armature is attached to the stator for rotation therewith, the armature having an axis parallel to the stator axis. One or more rotors, are spaced from the armature and coupled thereto by an axle for rotation about an axis of each rotor, each rotor rotating in a plane generally aligned with the armature axis. Each rotor includes one or more rotor magnets, with each rotor magnet generating a second magnetic field. The second magnetic field generated by each rotor magnet interacts with the first magnetic field to cause each rotor to rotate about the rotor axis. A linkage assembly drivingly connects each rotor to the stator to cause the armature to rotate about the armature axis thereby providing the unidirectional rotational motive power of the motor.

A low-cost sine-wave drive for a 3-phase permanent magnet synchronous AC machines (PMSM) in open-loop control is based on the measurements of two linear Hall sensors. The two Hall sensors are excited by a magnetic ring with the same pole number as the PMSM rotor magnet and sinusoidal flux distributions. The output signals of the Hall sensors are unified through a two-phase-type phase-lock-loop in order to reduce the impact of the sensor mounting non-uniformity during mass production. The peak torque and speed of motor is simply controlled by adjusting the amplitude of pulse-width-modulation carrier. Smooth torque control is achieved due to sinusoidal 3-phase currents. Such a simple sine-wave drive can be achieved with or without the assistance of a micro-controller unit (MCU). No current sensor is required for the motor phase current detection. This motor can be used in industrial applications where there is no strict requirement on torque response and constant speed control of PMSM machines.

A dynamoelectric machine comprises: a stator that comprises a plurality of stator poles arranged around a stator surface of revolution with a stator axis for the stator surface of revolution; at least one rotor that comprises a plurality of permanent rotor magnets arranged around a rotor surface of revolution with a rotor axis for the rotor surface of revolution that is coincident with the stator axis and with the rotor surface of revolution adjacent the stator surface of revolution; a drive shaft with a drive shaft axis of rotation that is substantially coincident with the stator axis coupled to the rotor for rotating the rotor relative to the stator about the drive shaft axis of rotation; and a at least one actuator for axially displacing the rotor surface of revolution along the drive shaft relative to the stator surface of revolution to change magnetic flux interaction between the stator poles and the rotor magnets; wherein at least one of the surfaces of revolution tilts with respect to the drive shaft axis of rotation.

A very thin fan motor with an attached heat sink that has high heat radiation and air cooling effects in a small, flat, thin package, that has a simple and easily assembled overall structure as a fan motor, and that has superior cooling efficiency. A flat fan mounted in various kinds of electronic equipment that need to radiate heat, and particularly mounted directly on the CPU, characterized by having a fan motor mechanism that comprises a heat plate that supports a rotor fan that can rotate in a central position and that has a contact surface that matches the shape of the external surface of the item (such as a CPU) to be cooled, rotor magnets that are part of the rotor fan and are positioned around the periphery on the surface of the heat plate, and a stator coil substrate, by having multiple metal heat radiation fins with excellent thermal conductivity, which are thin heat-radiating fins, arranged in parallel at a fixed interval on the heat plate pointing outward from the rotor fan as cooling heat-radiation fins, and by combining the function of cooling heat sink with the heat radiation fins that conduct the heat absorbed from the heat plate and radiate it away by the action of the air moved by the rotor fan.

A wave power assembly comprising a hull and a linear electric generator. The rotor is connected to the hull and the stator is arranged to be anchored at a sea / lake bottom. The generator is provided with an electromagnetic damping means in order to keep the pulsations of the axial force exerted by the stator on the rotor at a relatively low level, which damping means comprises geometric arrangement adapted herefor of at least some one of the stator winding, the stator slots and the rotor magnets. The invention also relates to a wave power plant built up from wave power assemblies according to the invention. Furthermore, the invention relates to a use of the wave power assembly and a method for generation of electric energy.

In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

A machine includes a stator and a rotor having a plurality of poles. Each pole is formed at least in part by a plurality of permanent magnets recessed within the rotor at a predetermined distance from an outer surface of the rotor. The distance is predetermined to minimize rotor flux variation near the outer surface during rotation of the rotor relative to the stator. Eddy current losses are thereby reduced.

Embodiments of the present invention effectively control, by a simple structure, floating of a rotor of a fluid dynamic bearing motor mounted in a hard disk drive. In one embodiment, a base is formed of a magnetic material. The attractive force caused by the magnetic force acts between a bottom of the base and a magnet unit that is constituted of a rotor magnet and a back yoke. This makes it possible to attract a rotor to the base against the buoyant force produced by a thrust bearing, and thereby to effectively control the rotation of the rotor. On the bottom of the base, at a position facing the magnet unit, a convex part protruding from the inner surface of the base is formed in a ring-shape. Adjusting the height, or the width, of the convex part makes it possible to control the magnetic back pressure applied to the rotor.

A wave power assembly comprising a hull and a linear electric generator. The rotor is connected to the hull and the stator is arranged to be anchored at a sea / lake bottom. The generator is provided with an electromagnetic damping means in order to keep the pulsations of the axial force exerted by the stator on the rotor at a relatively low level, which damping means comprises geometric arrangement adapted herefor of at least some one of the stator winding, the stator slots and the rotor magnets. The invention also relates to a wave power plant built up from wave power assemblies according to the invention. Furthermore, the invention relates to a use of the wave power assembly and a method for generation of electric energy.

An apparatus for converting between mechanical and electrical energy, particularly suited for use as a compact high power alternator for automotive use and “remove and replace” retrofitting of existing vehicles. The apparatus comprises a rotor with permanent magnets, a stator with a winding, and a cooling system. Mechanisms to prevent the rotor magnets from clashing with the stator by minimizing rotor displacement, and absorbing unacceptable rotor displacement are disclosed. The cooling system directs coolant flow into thermal contact with at least one of the winding and magnets, and includes at least one passageway through the stator core. Various open and closed cooling systems are described. Cooling is facilitated by, for example, loosely wrapping the winding end turns, use of an asynchronous airflow source, and / or directing coolant through conduits extending through the stator into thermal contact with the windings.

A fan (100) has an electronically commutated drive motor (ECM 52) with a stator (50) connected to a bearing tube (54) and a rotor (22) on a shaft (34). The shaft (34) is journaled in the tube (54) using passive radial magnetic bearings (16, 18) to minimize friction and wear, is axially displaceable with respect to the tube (54), and is drivingly connected to a rotor magnet (44) forming a first magnetic yoke (46). A second magnetic yoke (27) is connected to the shaft (34), and has an inner surface (59) defining a substantially cylindrical air gap (57) through which, during operation, a radial magnetic flux (55′) extends. A plunger coil (64) extends into the air gap (57) and is mechanically connected to the tube (54) so that, upon axial displacement of the plunger coil (64), the position of the shaft (34) with respect to the tube (54) changes.