The geometry of regulating transformers

Ferroresonant, ballast, and current-limiting transformers are similar in geometxy. Optimization of weight, losses, or cost can result in different choices for the shape (core or shell) and proportions of the lamination. In the ferroresonant transformer, the problem of saturation losses, noise and stray flux can be alleviated by altering the geometry to produce a magnetic circuit with nonuniform flux density.