Electromagnetic balancer with flux guides

The performance of an electromagnetically actuated balancer, without and with flux guides, is compared. The electromagnetic balancer is in the shape of a ring, with a number of grooves displaced around the axis of rotation. Steel balls are placed inside the grooves, and the electromagnet is used to generate electromagnetic force to initiate the movement of individual steel balls and consequently to vary the balancing status. The flux guides are placed above and below the grooves. Finite element analysis and experimental results show that the use of flux guides doubles the force/current ratio and thus reduces the required driving current in the electromagnet by 50%. This type of balancer is attractive for use in applications where rotational imbalance varies, for example, in high rotating speed servo track writers.