Transformer Eddy Current Dampers for the Vibration Control of Rotating Machines

Eddy current dampers are promising devices for the passive and semi-active vibration control of mechanical structures. Among them “motional” eddy current dampers are based on the Lorentz forces between a moving conductor and a stationary magnetic field. “Transformer” eddy current dampers are based on the forces that develop in a voltage driven electromagnet when part of the magnetic circuit is movable. Considering the simplicity of the layout, transformer configurations seem to be very promising as alternative to traditional rubber or squeeze film dampers to control the lateral vibration of rotating machines. The aim of the present paper is to investigate the dynamic behavior of “transformer” eddy current dampers integrated in a mechanical structure. To this end the bond graph formalism is adopted with the aim of evidencing the causality effects between the mechanical and electromagnetic parts. The modeling approach allows to propose a design procedure of the damper. The mathematical models have been validated experimentally using two test benches with different layouts and geometrical characteristics of the magnetic circuit.Copyright © 2006 by ASME