Variable voltage control systems as applied to elevators

K. L. Hansen: Because of the fact that the inherent speedtorque characteristic of the induction motor makes it less suitable than the direct-current motor to applications where masses of considerable inertia have to be accelerated and retarded at frequent intervals, the application of alternating-current power to certain classes of elevators presented a formidable problem. It appears that the system of control described in Mr. Bouton´s interesting paper was first thought of in connection with elevators as a solution to this problem.