Actuator (1) for a medical device (100), comprising an electromotor, a mechanical transmission, and magnetic coupling means arranged for transmitting a mechanical torque from the electromotor to the mechanical transmission when said electromotor is powered by an energy source, wherein said electromotor and a first part of the magnetic coupling means kinematically linked to the electromotor are arranged and hermetically sealed in a first casing module, and wherein said mechanical transmission and a second part of the coupling means kinematically linked to said mechanical transmission are arranged in a second casing module, said first and second casing modules comprising each complementary fastening means such that said first and second casing modules can be removably connected to each other in such a way that said first and second parts of the magnetic coupling means magnetically couple together upon connection of said first and second casing modules.
