Control Techniques Drives Continuous Slab Caster at Corus Steelworks

The Challenge

Continuous Caster 3 (CC3) was a completely new operation, designed to increase plant output 25%. Previous contracts for Control Techniques had been upgrades, re-utilising existing DC drives. On this project, the team considered the potential benefits of reduced motor maintenance and the reduced downtime from a switch to AC.

The Solution

Two new AC Drive Motor Control Centres (Form 4 MCCs), employing 60 AC Unidrive variable speed drives and Leroy Somer AC motors were supplied. New AC motors were also supplied by Control Techniques fitted with digital encoders and brakes on the vertical part of the caster. The drive control included onboard intelligence/specific application software, part of which included closed loop to open loop changeover in the event of a feedback device failure, thus ensuring the Caster continues to run.

The Benefits

Key to success was the PID-based load sharing system, pre-programmed into each Unidrive, using the on-board facility of the plug-in application modules. The software’s success, with reduced wear and tear and more consistent casting speed, is evident in the motor current trends. Rethread times are also much faster, with any limitations being factors other than the drives/electrics on the strands, the end result is a much more stable and reliable drive control system and superior speed control, leading to greater productivity and improved product quality.