Damping of mechanical drive train

A shaft sub-assembly of a generator comprising a rotor shaft and a disconnected shaft coaxial with the rotor shaft,

• wherein the shaft sub-assembly includes a damping mechanism for providing vibration damping between coaxially mounted rotor shaft and disconnected shaft of a drive train, the damping mechanism mounted between and connecting a first end of the rotor shaft and a first end of the disconnecting shaft, wherein the damping mechanism comprising:
• a friction disk;
• a Belleville spring;
• and
• an adjustment shim arranged to be mounted under a pre-load force within the rotor shaft exerting a force against the disconnected shaft, the damping mechanism arranged to be secured in the rotor shaft by a locking nut.