Producing 30t of frozen chips an hour, the McCain Food’s plant in Peterborough was looking to cut its energy consumption and update its old refrigeration facility. The on-site cold store, which operates 24/7, accounted for 60% of the site electrical loading. McCain also wanted more control of the refrigeration and to reduce the potential impact of harmonics.
The new refrigeration plant cut the compressors from 20 to seven. To run them, ABB installed seven variable-speed drives, with ratings ranging from 350 to 650kW.
The new drives helped to cut the site's loading by around 1MW. “They also enable us to over-speed the motor to get more refrigeration capacity, which we cannot do with traditionally controlled refrigeration plant,” says Paul Derbyshire, McCain electrical, control and automation engineer for Central Engineering.
The direct connection to the network removes the need for a complex multi-winding transformer and external filter equipment.