The electric motor has a stator (4b), a rotor (4a) with a rotor magnet (4c) and a medium through-opening (4e) between the stator and the rotor. The smallest inside diameter of the stator is as large as the largest outside diameter of the rotor magnet. The electric motor is a permanent magnet synchronous motor. The rotor magnet comprises of rare-earth material, particularly of neodymium iron boron and samarium cobalt.
