Trial production and experiments of linear actuator with HTS bulk secondary

To investigate characteristics of a linear actuator with high-temperature s uperconducting (HTS) bulk secondary, a short secondary type linear actuator has been designed and constructed. The actuator is comprised of an YBCO bu lk secondary (mover) and copper windings with iron core (primary). A zero-f ieid-cooled balk located at the center of the actuator plays a role of gene rating thrust, while four field-cooled (trapped field) bulb al e used for l evitation and guidance of the secondary. We measured the starting thrust fo rce and magnetic Weld distribution in the air gap. We developed a simulatio n program based on the finite element method (FEM) taking the voltage-curre nt (E-J) characteristics of the bulk into consideration to investigate elec tromagnetic behaviors within the bulk exposed to a time-varying magnetic fi eld,agreement between experiment and simulation Is good, and it validates t he simulation program and the presented assumptions in the numerical approa ch. Using the simulation program, we investigated the dependency of n-value and critical current density of the bulk material on tile magnetic flux de nsity in the air gap and the starting thrust force. Supercurrent density wi thin the bulk is a key factor for the magnetic flux density and the thrust force.