High temperature permanent magnet actuator for fail-safe applications

The paper describes the design and experimentally characterised of a high temperature, parallel-polarised permanent magnet electromagnetic actuator developed for fail-safe applications. The actuator is designed to operate in an ambient temperature of 230°C, has a stroke of 2mm and minimum force requirement, which can be maintained with zero current, of 1kN for the entire stroke. To minimise the mass of the final design, thermal modelling has been used to determine the acceptable current rating for the device, features were added to the pole faces to linearise the force characteristic, and high temperature grades of materials were used. A prototype actuator has been constructed and experimentally validated at the rated operating temperature of 230°C.