LARGE-AMPLITUDE LOW-FREQUENCY VIBRATOR

摘要

The vibrator acting on low frequency vibrations on a frame in a predetermined direction X'X comprises: a) a first structure having cylindrical pole pieces cylindrical about said axis X'X and provided at their peripheries with coils, and at least one means for creating a magnetic field for causing a magnetic flux to be established between the cylindrical pole pieces; b) a second structure essentially comprising a cylindrical ferromagnetic mass coaxial about the axis X'X and having cylindrical pole pieces whose peripheries are situated facing respective ones of the coils, and enabling magnetic flux to be established through the ferromagnetic mass; c) radial active magnetic bearings for holding the second structure radially relative to the first structure without making contact therewith; d) at least one detector for detecting vibrations along the axis X'X: and e) circuits for servo-controlling the current flowing in the coils as a function of signals delivered at least by the detector.