Fast-acting, long-stroke solenoids with two springs

A device with two oscillating springs controlled electromagnetically is studied both theoretically and experimentally. The mathematical model, based on finite-element analysis, consists of a dynamic model of motion which includes all relevant physical phenomena with the exception of eddy currents, which are then evaluated separately. The tests verify the mathematical model, quantify the possible time-versus-energy-input characteristic for a given stroke and volume, and allow comparison of this concept with a previously studied approach where repulsion forces are exerted on a moving permanent magnet. The latter is superior when the actuator is required to provide mechanical work in addition to fast motion over a long stroke, while the two-spring actuator is faster and uses less energy when motion alone is desired.<>