Next time your large crane creaks to a halt, consider the solution that QIT FER & TITANE chose for its harbour crane at Sorel-Tracy, Que. There are two cranes used for unloading ilmenite concentrate from ships and loading finished products onto the ships.
The cranes had several problems requiring attention. The brakes and the load trolley demanded too-frequent service and maintenance due to excessive demand on the "hold" and "close" brakes; there was no load distribution system; and brake coils were damaged. Uneven load distribution also led to repeated failure of the motors used to move the cranes. The system had no automation not even alarm indicators.
The solution came from ABB, which is proud of its part in the upgrade project. Phase I was done in 1998-99 by replacing the 600-V busbars with 15,000-V reels with 600-V transformers. Phase II was accomplished during the winter of 2002. It included installing 630-kW ACS600 AC drives on the "hold" and "close" motors. Another 200-kW drive was fitted on the trolley. A specialized AC80 controller was installed to automate the "hold" and "close" operation in tandem. The drives are designed to control activity sharing between the motors, to regulate load speeds up and down, and to optimize load torque and speed ratio (which avoids overheating at low speeds). As well, the boom motor was replaced with a 60-kW ACS600 AC drive.
The upgrade of the first crane is complete, and the benefits are many. The time needed to train an operator has been shortened. Operation is easier thanks to the installation of multi-functional automated levers in place of the old control arms and buttons. Automated control and alarms ensure the cranes run within specified parameters. Maintenance is reduced. QIT is planning to modernize the second crane this winter.
Contact your local ABB Motors & Drives representative or go to www.abb.ca