An electric machine comprises a sealed outer casing defined by a body and by a cover coupled to the body, a stator and a rotor the latter two being mounted inside the casing; the stator is of a wound type and comprises a core having at least two pole pieces and a plurality of windings each defined by a conductor wire wound in a plurality of coils around the pole pieces; the electric machine further comprises a plurality of plastic components located inside the casing and made of a plastic material whose moisture absorption at saturation is less than 0.8%, having insulating and/or supporting and/or cooling functions.