Study of a linear Halbach passive magnetic damper

High voltage ultra-fast circuit breakers are operated with fast actuators. They are capable of generating impulsive force to swiftly open electrical contacts in a couple of milliseconds. Opening of the contacts with high velocities implies a need for a timely and controllable damping. An efficient damping mechanism then is crucial to attain an appropriate actuation performance and secure a long lifetime. In this paper a finite element model of a Halbach magnet array based magnetic damper and a corresponding experimental prototype is described. It was found that a uniform and high radial component of the magnetic flux density is necessary in order to achieve high damping force. The radial magnetic field can be controlled via thickness and magnetization direction of the ring magnets which are used to create the Halbach magnet array. Finally, it is also shown that the concept provides a frictionless collision free damping demonstrating its potential to be used in fast circuit breakers.