Abstract: A tubular stator capable of creating a magnetic field having both linear and rotary components comprises a tubular magnetic frame formed from longitudinal magnetic elements which are angularly spaced. The magnetic elements have teeth which extend radially inwardly. Circular induction coils are disposed between the teeth and undulating coils are disposed longitudinally between the magnetic elements. A magnetic sleeve surrounds the magnetic frame.An electric motor comprises a cylindrical rotor mounted within the tubular stator so as to be rotatable and translatable.

Abstract: A device for maintaining a vacuum in a compartment of a rotating member includes a collector which is mounted over an orifice of the rotating member. The collector has an end wall with an annular aperture extending axially of the rotating member. The aperture is selectively sealed by an annular valve member which permits communication of the compartment with a high-vacuum pump. The valve member may be of a magnetizable material and may be moved axially by a fixed control coil. Sealing members are provided for sealing the compartment of the rotating member with respect to a fixed member when the compartment is in communication with the vacuum pump.