Control of direct current hoists in iron and steel mills

The control problem discussed in this paper is confined entirely to a typical example of a skip hoist. An outline of the conditions existing in the case of this particular application is given in which the load on the hoist is divided into three parts, namely, the friction load, the inertia of moving parts, and the useful work in hoisting the net load. The proper cycle of operations is determined, which in turn determines the required characteristics for the motor and controller which are together considered as a unit. The details of this d-c. skip hoist control are described and illustrated.