the invention relates to a centrifugal separator for separation of at least two components of a fluid mixture which have different densities . the centrifugal separator comprises a rotor arranged for rotation about a vertical axis of rotation and having a rotor wall which surrounds a separating chamber within the rotor , with an inlet adapted to feeding the fluid mixture into the rotor &# 39 ; s separating chamber , and at least one outlet adapted to discharging outwardly from the rotor a component separated from the fluid mixture . a rotor shaft supports the rotor and is drivably connected to a motor for rotation of the rotor about the axis of rotation . a hub is provided outside the rotor , and the hub and the rotor shaft are arranged to be connected together from the outside of the rotor by means of a lockable and releasable fastening which is configured to lock the rotor shaft relative to the hub in both a torque - transmitting and an axial force - transmitting way .