Abstract:
A wind turbine has its blades (1) arranged so that they can pitch towards stall against the action of a spring (15) or other resilient device. The centrifugal loading on the blades (1) acts against the spring (15) in a direction to shed power by pitching the blades (1) towards the stall. The torque loading provided by the generator or other power conversion device acts to pitch the blades (1) in the opposite direction, so as to reduce the amount of load shedding whenever the power is being extracted from the wind turbine.
Abstract:
A permanent magnet electrical machine comprises a first substantially planar member (9, 10) and a second substantially planar member (3) arranged substantially parallel to the first substantially planar member. The first and second members are rotatable relative to each other about a common axis substantially perpendicular to the planes of the first and second members. The first member (9, 10) is provided with an annular array of permanent magnets (7, 8) coaxial with the common axis and configured to provide a substantially axial magnetic field passing through the second member. The second member (3) is provided with a first annular array of flat coils (1) coaxial with the common axis and arranged substantially side-by-side in a first layer and with a second annular array of flat coils (2) coaxial with the common axis and arranged substantially side-by-side in a second layer. The coils (2) of the second array are offset in a circumferential direction relative to the coils (1) of the first array.
Abstract:
A synchronous alternating current generator incorporates a braking mechanism which comprises a coil (21) providing a predetermined inductance and a predetermined resistance, and switch means (22) for connecting the coil across an output of the generator.
Abstract:
A synchronous alternating current generator incorporates a braking mechanism which comprises a coil (21) providing a predetermined inductance and a predetermined resistance, and switch means (22) for connecting the coil across an output of the generator.
Abstract:
A permanent magnet electrical machine comprises a first substantially planar member (9, 10) and a second substantially planar member (3) arranged substantially parallel to the first substantially planar member. The first and second members are rotatable relative to each other about a common axis substantially perpendicular to the planes of the first and second members. The first member (9, 10) is provided with an annular array of permanent magnets (7, 8) coaxial with the common axis and configured to provide a substantially axial magnetic field passing through the second member. The second member (3) is provided with a first annular array of flat coils (1) coaxial with the common axis and arranged substantially side-by-side in a first layer and with a second annular array of flat coils (2) coaxial with the common axis and arranged substantially side-by-side in a second layer. The coils (2) of the second array are offset in a circumferential direction relative to the coils (1) of the first array.