The electrodynamic exciter system designed for the frequency range from 10 Hz to 50 kHz (cylindrical moving coil) has been equipped with an air bearing (diameter: 50 mm; air gap: about 20 µm) two versions of which have proved their worth (one or two rings of orifices) as has been observed with other state-of-the-art air-borne vibration exciters: Any rocking and transverse motion as well as resonance effects can widely be suppressed at frequencies up to about 5 kHz. As suppression is not sufficient at higher frequencies, the system was equipped with a special two-channel laser-interferometric measurement system. This allows for a determination and later elimination of the disturbing rocking motion.
High-frequency acceleration exciter
(air-borne moving part with calibration object)