| 摘要 |
A direct drive rotary generator comprises inner and outer coaxial cylinders 19,20 one of which is stationary whilst the other is rotated by the prime mover, each cylinder carrying a number of interleaved spaced annuli 31,32 which support respective magnets and coils. In an example, cylinder 19 may form the stator and a series of circular/elliptical coils 34,35,36 whose separation is less than 10% of their diameters arranged about each annulus 31, the outer annuli 32 carrying respective axially magnetised permanent magnet 37,38 of ferrite material spaced at the same pitch as the coils. Grooves in the cylinders accept the annuli. Multi- phase generation may be achieved by grouping the coils on each annulus 120º apart and/or circumferentially displacing each annulus 120º with respect to the preceding one (figs12,13 not shown), cogging forces being reduced. The magnets may be circumferentially spaced sufficiently to avoid lateral flux leakage (fig 9 not shown) or the magnet annuli may comprise a an annular ferromagnetic disc with half thickness magnets mounted on either side of the disc (fig11 not shown). The magnets and coils may be encapsulated and a non-magnetic and non-conductive facing disk may be adhered to either side of the coils. |
