K-factor Rated Transformers are wound magnetic devices that are de-rated per an ANSI Standard that establishes the Transformers capability when supplying nonsinusoidal load currents. This de-rating has been incorporated to handle the dramatic growth in the use of equipment incorporating switching power supplies. Equipment such as electronic ballasts, UPS systems, variable speed drives, fax machines, personal computers and monitors, and so on. This type of equipment creates harmonic currents that generate heat in distribution equipment and Transformers.