A low loss transformer using a rotating magnetic field

A type of transformer with reduced iron loss, which is excited by a semirotating magnetic field, has been investigated. Factors (method of excitation and slits in the core) affecting iron losses are examined. The iron loss of this type of transformer can be reduced below the material loss as measured for normal AC excitation by introducing a slit which cuts the eddy current path, and by improving the method of excitation.>