A device for positioning a workpiece for machining has a bench, which is mounted movably at a base and to which the workpiece can be fastened. Polysilicon is doped with barium and melted in a silica crucible containing less than about 0. The first inclination refers to a first average angle with respect to horizontal. The commutator is fitted onto the electric motor rotor shaft. The shaft penetrates through the housing and the circuit board and having a first end and a second end.