Looking at the photo, you can see there is a shape coming out of the exit side of the mill Shape may include stretched edges or center buckle. The operator can see this when operating the mill. Many shape controls are adjusted by the operator at speeds up to 7,000 FPM.
DC motors can do everything AC drives can do, however, the disadvantage of a DC motor is that it requires brushes and these types of motors are open and require some maintenance. Rolling mills usually run around the clock, and DC motors may cause downtime and are expensive to maintain such as the continuous need to be machined, and of course, the brushes wear. However, the amount of maintenance on a DC motor, if maintained properly, can be infinitesimal.
A pit type coil car receives coils from the rack over a pit. The coil car places the coil onto the single-end hydraulic expanding mandrel uncoiler. The uncoiler is equipped with an electric motor regenerative brake or a water cooled brake system.
Practically all new rolling mills today are equipped with hydraulic screwdowns for hot or cold rolling. A disadvantage of mechanical screwdowns is the fact that you cannot adjust accurately while the screwdowns are under pressure.
