Abstract: A hand held device with built-in motor for rotational drive of small tools. The hand held device includes an outer housing consisting of a larger diameter rear part which contains an electric driving motor, an intermediate part of small diameter which contains motion transmitting means, and a front part in which is mounted a holder for the tool to be driven. The electric driving motor is a brushless motor having a rotor encapsulated in a sealed insulating enclosure and includes permanent magnets covered with a layer of conducting metal and a stator made up of multi-phase winding coils embedded in a molded plastic material. The motion transmission means consists of non-contacting magnetic coupling means.

Abstract: A brushless electric micromotor comprised of a rotor, a shaft and a tube-like part and permanent magnets rotatably mounted and hermetically sealed in a rotor housing, said shaft being supported in bearings. The permanent magnets have their co-axial surfaces coated with a layer of an electrically conductive metal. The micromotor further comprises a stator co-axially surrounding the rotor housing and comprising field windings regularly arranged with equal angular distances in the stator housing made of magnetic material.