An electric machine, for example, a motor, is provided. The machine or motor includes a stator, a rotor, at least one main bearing for supporting the rotor relative to the stator in a main range of speeds and at least one secondary bearing suitable for supporting the rotor relative to the stator when the first main bearing is faulty. Each secondary bearing is a passive electrodynamic bearing and includes at least one permanent magnet and a moveable electric conductor element.

The present disclosure relates to a stiffness enhancing mechanism for a magnetic suspension bearing, a magnetic suspension bearing including the stiffness enhancing mechanism, and a blood pump. The magnetic suspension bearing comprises a stator with stator teeth and a rotor disposed within the stator. The stiffness enhancing mechanism comprises: a rotor permanent magnet, a stator permanent magnet, and an axial driving body. The rotor permanent magnet and the rotor of the magnetic suspension bearing form a rotor assembly, which has an asymmetric structure with respect to the main plane (P) of the rotor. The stiffness enhancing mechanism is configured such that the stator permanent magnet generates a radial attractive force to the rotor permanent magnet, and the axial driving body generates an axial repulsive force to the rotor permanent magnet, wherein the magnitude of the axial repulsive force is variable with a change of an axial distance between the axial driving body and the rotor permanent magnet. The stiffness enhancing mechanism can increase the torsional stiffness of the rotor of the magnetic suspension bearing and facilitate the miniaturization of the magnetic suspension bearing.

A vertically mounted and magnetically driven power generation apparatus has multiple shelves vertically arranged and spaced apart. Each shelf has a through hole tapering downwards. A spindle is mounted through the multiple through holes. A motor driving the spindle and a primary power generator driven by the spindle and located below the motor are mounted around the spindle. Because of the weight of the primary power generator, adding additional weight is not need. A magnetic driven member is mounted around the spindle and located within a corresponding through hole. Multiple magnetic drive assemblies are mounted on inner walls of the multiple through holes. Each magnetic driven member is subject to forces of magnetic repulsion caused by first and second magnetic drive members of a corresponding magnetic drive assembly for the spindle to be rotated under a friction-free condition to enhance torque and rotation speed of the spindle.

An electric machine comprises a rotor from which a magnetic field emanates and a stator that produces a magnetic field that interacts with the magnetic field emanating from the rotor. The stator comprising a pair of windings symmetrically positioned with respect to the rotor. A displacement of the rotor causes an increase in magnitude of a magnetic flux induced by the rotor in one winding of the pair of windings and a decrease in magnitude of a magnetic flux induced by the rotor in the other winding of the pair of windings. A driver can make the electric machine operate in an active electromagnetic bearing mode and in a passive electromagnetic bearing mode. In the active electromagnetic bearing mode, the driver applies a suspension signal component to at least one winding of the pair of windings. This causes the magnetic field produced by the stator to have a component that exerts a suspension force on the rotor through interaction with the magnetic field emanating from the rotor. In the passive electromagnetic bearing mode, the driver interconnects the pair of windings of the stator with each other so that the increase in magnitude of the magnetic flux in the one winding and the decrease in magnitude in the other winding of the pair of windings generates a suspension current in the pair of windings. The suspension current causes the magnetic field produced by the stator to have a component that exerts a restoring force on the rotor counteracting the displacement.

The invention provides a way re-center a rotor's central longitudinal rotational axis with a desired system longitudinal axis. A pair of planar semicircular permanent magnets are pieced together to form a circle. The flux from each magnet is pointed in in opposite directions that are both parallel with the rotational axis. A stationary shorted circular winding the plane of which is perpendicular to the system longitudinal axis and the center of curvature of the circular winding is positioned on the system longitudinal axis. Upon rotation of the rotor, when a transverse displacement of the rotational axis occurs relative to the system longitudinal axis, the winding will experience a time-varying magnetic flux such that an alternating current that is proportional to the displacement will flow in the winding. Such time-varying magnetic flux will provide a force that will bring the rotor back to its centered position about the desired axis.

A kinetic energy recovery system may include a first rotatable assembly, attachable to and jointly rotatable with a vehicle wheel assembly, and a second rotatable assembly, rotatably mountable on a wheel axle of the vehicle wheel assembly and independently rotatable about the wheel rotation axis with respect to the first rotatable assembly. The first and second rotatable assemblies may include a first and a second plurality of magnets, respectively. The second rotatable assembly may be rotatable about the wheel rotation axis by a magnetic field produced between the first plurality of magnets and the second plurality of magnets. The system may include a stator, mountable about the wheel axle. The second rotatable assembly may produce an electrical current in the stator responsively to a rotation of the second rotatable assembly about the wheel rotation axis.