ABB motors and drives are an integral part of an advanced new SCADA controlled ventilation system for the Clyde Tunnel. The new ventilation system is controlled by a SCADA controller communicating over a fibre optic network with the drives controlling the fans.
Bob McKinnon, Tunnel Master for the Clyde Tunnel, says: "The new drives give us fine control of the ventilation fans. In the event of a fire, we need to switch on all 18 fans at once, which the previous system could not do. Using the SCADA system, we can monitor the carbon dioxide levels in the tunnel and tune the speed of the drives to give the right tunnel air conditions at the minimum speed, saving electricity.
Previously, speed control of the fans was achieved using seven-speed motors controlled by resistance banks. We had numerous problems with stepping relays burning out and the old starters could only switch on one motor at a time, so it was clear we needed a complete new system."
McKinnon asked Paul Ducker Systems (PDS) to design a new ventilation system, using the existing fans but incorporating a more advanced control network. PDS chose ABB motors and drives, 12 to drive the supply fans and six for the exhaust fans. Supplied and installed by ABB Drives Alliance and Motor Service partner EDC (Scotland), the ABB drives were chosen because they were one of the few variable speed drives that could be operated using a SCADA based control system. The ventilation system is a semi transverse system, in which half the exhaust air is extracted by the exhaust fans and half leaves through the tunnel portal.
Built in 1957, the 760m long tunnel links Govan south of the River Clyde with Whiteinch in the north. A twin tube design, it was built to carry 9,000 vehicles a day but currently handles 60,000.