A balancer of a washing machine having improved balancing performance. The balancer includes a balancer housing having an annular channel therein, at least one mass movably disposed in the channel at least one groove recessed in an inner surface of the balancer housing so as to accommodate the mass, and at least one magnet coupled to an outer surface of the balancer housing to restrict the mass accommodated in the groove when an RPM of the drum is within a specific RPM range. The magnet is configured as a plurality of N poles and S poles which are arranged alternately, and the outermost pole of the magnet among the plural N poles and S poles has a relatively shorter length than another adjacent pole.

A coupling for transmitting torque from a drive to a load has a first connection for connection with the drive, a second connection for connection with the load, and an elastic element for vibration damping and between the first and second connections in the energy transmission path therebetween. An actuator carried on the elastic element has a base body and a centrifugal mass body rotatable relative thereto. One of the two bodies carries an electrical conductor and the other of the two bodies carries a permanent magnet. The conductor is in a magnetic field of the permanent magnet. Thus a flow of current through the conductor makes the centrifugal mass body exert an angular force on the base body to compensate for rotational vibrations.

A dynamic damper device includes first and second rotary members disposed in axial alignment, a third rotary member disposed to be rotatable together with and relative to the first and second rotary members, and a magnetic damper mechanism. The first and second rotary members are coupled to be non-rotatable relative to each other. The magnetic damper mechanism is configured to magnetically couple the first and second rotary members and the third rotary member. The magnetic damper mechanism is configured to generate a resilient force when a relative displacement is produced between the first and second rotary members and the third rotary member in a rotational direction, the resilient force serving to reduce the relative displacement.

A balancing device for each rotating piece, the rotating piece defining an axis of rotation, the balancing device including: a fixed portion, a mobile portion defining a central axis. The balancing device constrained to the rotating piece so that the central axis substantially coincides with the rotation axis. The balancing device including at least one eccentric mass, rotatable around the central axis and not balanced with respect to the central axis. The balancing device further including apparatus for movement of the eccentric masses, including a magnetic brake and being able to rotate the eccentric masses, with respect to the rotating piece around the central axis.

Systems and methods are disclosed herein that include providing an active torsion damper control system that includes a rotatable component (206) and a rotatable measurement interface (302) disposed on the rotatable component, the rotatable measurement interface having at least one torsional strain gauge configured to measure a strain of the rotatable component, a torque management (306) computer configured to determine a resonant frequency of the rotatable component and a corrective torque needed to be applied to the rotatable component to excite the resonant frequency as a function of the measured strain, and a correction motor (308) configured to impart the corrective torque on the rotatable component.