High-Speed Applications for Electromagnetic Propulsion Technology

In this thesis, different types of the magnetic lead screw systems are considered, and the effects of the key design parameters, such as magnet thickness, air-gap length, pole-pitch, number of pole-pairs, dimension etc. on the force/torque transmission are investigated. Moreover, research into the realisation of helical magnetisation distribution employing a novel impulse magnetisation process is undertaken, in order to reduce the complexity and cost of manufacture. This avoids the complex and/or time-consuming methods, which may require the assembly of a large number of small magnets to approximate helical magnetisation distribution. A prototype reluctance type magnetic screw system is realised, it consists of a double start mechanical screw and a permanent magnet nut equipped with impulse magnetised cylindrical permanent magnets, using purpose designed double-sided impulse magnetising fixture. Furthermore, a test-rig to measure the transmitted force is developed and used to compare the predicted and measured results.