Case Study: KAAL Warm Mill Upgrade

Scope: Design, manufacture, install and commission a replacement control and drive system for a four high reversing aluminium rolling mill. The mill consisted of two main drive DC motors, each rated at 2.4MW fed by an MG set, entry and exit coilers powered by three 750kW motors, an edge trimmer, pinch rolls, deflector rolls and belt wrappers.

New Siemens 6RA24 DC converters were used to control the mill DC motors, and for field excitation of the synchronous motor, DC generators and main drive motors. A Siemens S5-135U PLC system was used to interface the converters and provide the necessary tension control, diameter calculations, inertia compensation, strip length measurement, automatic slowdown, threading and coil removal functions. The PLC also interfaced with the mill supervisory VAX via an Ethernet link.

A staged installation and commissioning process was used to ensure that each section of the new system was operational before changeover. This increased mill uptime and minimised the risk of implementing the new system.

Client: KAAL