Passive Magnetic Levitation of Rotors on Axial Electrodynamic Bearings

The present paper presents a new modeling approach for null flux axialelectrodynamic bearings. Such approach allows defining stability bounds forrotors supported with this type of passive magnetic suspension. The linearizedmodels are developed using the bond graph methodology to better understandthe multiphysics nature of the magnetic suspension. The adoption of complexvariables together with the bond graph formalism is introduced in order toreduce the complexity of the system's equations. Rules for the use of thisapproach are established and demonstrated.The validation of the proposed models is developed comparing experimentaland analytical results. To this end, a test rig, devised to achieve fullypassive stable magnetic levitation, is described and used to produce the experimentaldata. Furthermore, experimental evidence of stable, fully passive magneticlevitation of a rotor is presented and discussed.The modeling procedure presented and validated experimentally constitutesa valuable tool for the design of magnetic suspensions including electrodynamicbearings