Alternating-current controllers for steel mills

The induction motor with either squirrel cage or wound rotor is practically the only type of alternating current motor used for general industrial purposes in this country and therefore the author has confined his paper to considerations of the control problems offered by induction machines. The various types of alternating current controller in use are described and illustrated and the advantages and disadvantages of each type as well as its limiting capacities are discussed. A number of typical examples of installations of alternating-current controllers in mill work and allied industries is described.