Speed control

A speed control arrangement for a rotatable member driven from an energy source the speed control arrangement including an eddy current brake comprising a rotor of electrically conductive material coupled to the rotatable member to be driven therewith, a magnetic circuit including a magnet and arranged to be coupled to the rotor such that rotation of the rotor causes eddy currents to be induced in the rotor material to produce a braking torque against its rotation and actuation means responsive to a change in driving torque applied to the rotatable member by the energy source to alter the coupling between the magnetic circuit and the rotor to produce a change in the braking torque on the rotor corresponding to the change in driving torque in which the magnetic circuit comprises a permanent magnet attached to a substantially U-shaped magnetic shunt member such that an air-gap exists between the limbs of the member and in which the rotor is a disc.

A speed control arrangement for a rotatable member driven from an energy source the speed control arrangement including an eddy current brake comprising a rotor of electrically conductive material coupled to the rotatable member to be driven therewith, a magnetic circuit including a magnet and arranged to be coupled to the rotor such that rotation of the rotor causes eddy currents to be induced in the rotor material to produce a braking torque against its rotation and actuation means responsive to a change in driving torque applied to the rotatable member by the energy source to alter the coupling between the magnetic circuit and the rotor to produce a change in the braking torque on the rotor corresponding to the change in driving torque in which the eddy current brake includes a plurality of magnetic circuits movable relative to the rotor.

A speed control arrangement for a rotatable member driven from an energy source the speed control arrangement including an eddy current braking comprising a rotor of electrically conductive material coupled to the rotatable member to be driven therewith, a magnetic circuit including a magnet and arranged to be coupled to the rotor such that rotation of the rotor causes eddy currents to be induced in the rotor material to produce a braking torque against its rotation and actuation means responsive to a change in driving torque applied to the rotatable member by the energy source to alter the coupling between the magnetic circuit and the rotor to produce a change in the braking torque on the rotor corresponding to the change in driving torque including a plurality of magnetic circuits fixed relative to the rotor.

A speed control arrangement for a rotatable member driven from an energy source the speed control arrangement including an eddy current brake comprising a rotor of electrically conductive material coupled to the rotatable member to be driven therewith, a magnetic circuit including a magnet and arranged to be coupled to the rotor such that rotation of the rotor causes eddy currents to be induced in the rotor material to produce a braking torque against its rotation and actuation means responsive to a change in driving torque applied to the rotatable member by the energy source to alter the coupling between the magnetic circuit and the rotor to produce a change in the braking torque on the rotor corresponding to the change in driving torque in which the magnetic circuit comprises a permanent magnet attached to a substantially U-shaped magnetic shunt member such that an air-gap exists between the limbs of the member in which the shunt member of each magnetic circuit is shaped such that the relationship between braking torque and magnetic coupling varies in the same way as the relationship between the change of torque of the energy source and movement of the magnetic circuit.