Three-phase alternator with a positive non-flexibly coupled fan wheel

A three-phase alternator adapted to be driven by an internal combustion engine at variable speeds, comprising:

• a V-belt pulley (22);
• a rotor shaft (18,21) to which said V-belt pulley (22) is joined firmly to rotate together with the rotor shaft;
• a fan wheel (23), driven by the V-belt pulley (22) by a force-transmitting coupling, including
• a hub for holding a ball bearing internally thereof;
• means for axially resiliently connecting said hub to said fan wheel;
• two ball bearings, each having an inner ring (25,28), an outer ring (26,29), and interposed rolling balls (24,27);
• the inner ring (24) of the first one of said ball bearings (24,25,26) being seated on the shaft (18,21);
• the outer ring (26) of said one ball bearing being fitted into the fan wheel;
• the inner ring (28) of the second ball bearing (27,28,29) being seated on the shaft (28,21);
• the outer ring (29) of the second ball bearing (27,28,29) being seated in said hub;
• and adjustable means (34) for bearing against said inner ring (20) of said second ball bearing (27,28,29) for producing a predetermined bias force, through said bearings, for said axially resilient connecting means.