In constructing large rein-forced-concrete buildings, usually a separate hoist is used to hoist the steel and lumber for the forms. This hoist may be equipped with either an electric motor or an engine, depending upon the general arrangement of the plant. These hoists are usually of the single-drum type.

Fig. 137. Regulating and Reversing Controller for Motor of Fig. 136.

Fig. 137. Regulating and Reversing Controller for Motor of Fig. 136.