Steel mill controllers from the operator´s standpoint

The writer discusses control problems from the operator´s standpoint, in connection with bloom mill and rolling mill machinery. The most important consideration is that no provision for emergencies can be allowed, and when the ingot or bloom leaves the furnaces for the rolls it must be kept moving until it reaches the cooling beds. Any interruption in this cycle means scrap material and lost time. To fulfill these requirements the equipment must always stand up to the service and be as nearly fool-proof as possible. The full magnetic controller in the writer´s opinion meets the above requirements better than any other type. The requirements of the different classes of machinery are tabulated and from this tabulation it is shown that the control can be standardized in four distinct types one or the other of which will meet all conditions of mill equipment: 1. Full reverse single-speed type. 2. Full reverse multi-speed type. 2-a. Full reverse multi-speed type with dynamic braking. 3. Non-reverse push-button type. In conclusion the author points out that the conditions to be met and their solution should be kept as uniform as possible and the aim should be towards simplicity. The expense of duplication would be avoided by standardization of parts, and this would also permit comparison of different makes of apparatus on an equal basis.