In a vertical axis wind generator incorporating a circular turbine supported by an uppermost part of an upstanding support, a stator surrounding and coaxial with the turbine comprises an upper annular body positioned adjacent and or above the upper end of the turbine and having an uppermost surface which over at least a part of its radial width is inclined downwardly towards the vertical axis, a lower annular body positioned adjacent and/or below the lower end of the turbine and, extending lengthwise between the annular bodies, a plurality of circumferentially spaced blades define the venturi. Preferably, the undersurface of the lower annular body over at least a part of its radial width is inclined upwardly towards the vertical axis. The wind energy convertor will convert into mechanical energy the energy of a wind blowing in any direction and is capable of self-starting, irrespective of the direction of the wind.