Abstract: Electric machine in which parts subject to magnetostrictive forces are sized and configured in a particular manner. Such parts (1) have radial dimensions that vary along the axial direction. The pads are formed by laminations (12) that are assembled in an alternated arrangement, either individually or by groups, and have differing inner and/or outer dimensions and/or shapes. Such a solution is instrumental in reducing the noise caused by vibrations brought about by the electromagnetic forces generated by the machine.

Abstract: A pump driven by an electric motor includes a stator, a rotor cooperating with the stator, a rotating drive-shaft associated to the rotor, a hermetically sealed chamber, and a disk wheel within the sealed chamber and joined to the drive-shaft. The sealed chamber is sealed by a first ring gasket around the drive-shaft and in the sealed chamber and a second ring gasket fixed to the drive-shaft and against the first ring gasket. The first and second ring gaskets are pressure coupled to each other. At start-up of the motor, the rotor or the stator is allowed to turn freely for a certain initial arc without torque being applied to the coupling so that inertia can be accumulated to overcome resistance of the coupling when the torque is subsequently applied to the coupling.