5 using a cage and counterweight arrangement. These ar e often confgur ed for use with push button cage contr ol. Drum hoists, both single drum and double drum, ar e the most fr equently used type of hoisting system. W ith multi-layer coiling the double drum hoist is fr equently used for lengths of wind to 2500 metr es, but can be used for lengths of wind gr eater than 3000 metr es. Although normally winding in balance, the range of brake tor que r equir ed during emergency braking r equir es some form of brake contr ol system to pr ovide acceptable r etar da - tion levels under all winding condi - tions. The contr ol of emergency braking r etar dation for single drum hoists is particularly pr oblematic due to the high out of balance loads and gr eat variation in the natural rates of r etar dation for dif fer ent hoisting conditions. FLSmidth has extensive experience in the design of suitable brake contr ol systems.