Electric lifts

This paper deals with the ground covered by the electrical rather than the mechanical side of lift engineering. The evolution of the lift is outlined, and a description is given of the most suitable types of installations for various conditions of service. The component parts are discussed in some detail, especially the electric drive and control, and the conclusion is drawn that the Board of Trade will exercise more control in the future, particularly with regard to the mechanical design of safety devices. The use of squirrel-cage motors is considered, and it is shown that there is a big future for the " double-deck " type, which has a speed-torque characteristic similar to that of a slip-ring machine. Floor-levelling devices, too, are coming more into use as a result of the higher cage speeds now prevalent.