Abstract: Installations of this type generally comprise an electron-beam generator connected to a chamber for receiving the workpieces to be welded in which a vacuum can be created by a vacuum pump. According to the invention, the vacuum chamber comprises a first workpiece chamber (5) of small volume and a second workpiece chamber (15) of substantially greater volume. The two chambers are connected by a slide valve (10) in region of the path of the beam (I) generated by the electron-beam generator (2). The ratio of the volume of the two workpiece chambers (5, 15) lies preferably between 5 and 1000, for example at approximately 100.

Abstract: An electric multiphase motor with a closed ring housing and a pole piece star which is inserted therein after being wound from the outside, the pole piece star having axially integral pole pieces which are arranged in star-like fashion around a hollow cylinder and inserted therein in which great strength of the pole star is achieved while at the same time ensuring good electrical data by inserting the radially inner ends of the pole pieces into the hollow cylinder as individual parts up to the bore of the hollow cylinder so that after the assembly of the motor no further finishing operations are required and welding the radially outer ends of the pole pieces to the inside to the surrounding ring housing by electron beam welding starting at the outer circumference of the ring housing.