Drives & Controls June 2022

41 www.drivesncontrols.com June 2022 / SYSTEM INTEGRATION AND PANEL-BUILDING n Planning ensures that trawler switchboard is shipshape T he Scottish marine electrical services business NU-Design needed help when designing a switchboard for a distribution and motor control centre (MCC) that was being installed in a new trawler, the Endeavour V. The MCC panels feed all of the electric motors on board the vessel. The main switchboard feeds-out to two 415V distribution boards and 415/230V transformers which, in turn, supply loads on board the vessel. The Endeavor V was designed by Macduff Shipyards and its hull was built at the Finomar shipyard in Szczecin, Poland. The specifications and requirements for the vessel’s motor control centre were very specific. They had to comply with marine regulations, as well as being sized and configured to fit in a small onboard switchroom. An added pressure was that the project needed to be completed within a tight timeframe because the switchboard could only be installed while the Endeavour V was being built on land. Once this build was completed, the window of opportunity to install the switchboard would be lost. Maritime switchboards are different from land-based switchgear, mainly because of the need to be powered by generators. The Endeavor V’s switchboard had to accommodate two on-board generators as well as an onshore mains supply connection, with a full capacity of around 500A. To help design the switchboard, NU-Design contacted Rittal. According to NU-Design electrical design engineer, Peter Buchan, the reasons for choosing the enclosure-maker as a partner included its ability to supply marine- approved equipment, and the ease of assembling its modular designs. Rittal created an initial design using its own in-house configuration software. After an initial review, the design was reconfigured into an L-shape, so that it could be located in a tight corner inside the Endeavour V’s switchroom. To complete the build within the tight project timeframe, the installation and commissioning were completed by specialist electricians from RD Downies, a Scottish marine electrical and engineering company which is based in Fraserburgh. For this project, the design engineers needed to comply with further rules for the busbar design, including achieving fault-rating certification and ensuring that the copper busbar met a minimum cross-sectional area. In addition, the power distribution and motor-control sections needed to be separated within the L-shaped switchboard, both to provide clarity for the operator and to simplify routine maintenance. Once the busbar systemhad been installed, with a bus coupler and a special connection for the onshore mains connection, the engineers had to develop a system that would accommodate the out-going cable connections within the limited space available in the switchboard. The final design included the ability to monitor the power of the generators, a set of synchronising controls, and specific marine requirements, such as clear labelling of the controls and circuit feeders, interlocking of components, the provision of handrails, achieving high IP ratings, and producing an easy-to-followmaintenance guide. Following the success of the switchboard for the Endeavour V project, a second switchboard was ordered for another NU- Design fishing trawler. n There are different requirements when designing switchboards for use on board sea-going vessels, compared to land-based installations. A recent project involving a new-build Scottish trawler illustrates some of these challenges. The switchboard had to be configured into an L-shape to fit into a tight corner in the vessel’s switchroom (above) Designing and building the switchboard for the Endeavor V trawler (left) posed some challenges