Abb Limited [Oil and Gas] offers Multi-Ratio Externally Mounted Bushing Current Transformer. Abb Limited [Oil and Gas] is an ISO 9001 certified company. Abb Limited [Oil and Gas] also offers various types of types of transformers and sensors. The Multi-Ratio Externally Mounted Bushing Current Transformer, Model OBCT, is designed for use on existing power transformers or circuit breakers for relaying purposes. The Multi-Ratio Externally Mounted Bushing Current Transformer has minimum installation time since it is not necessary to remove bushings or open the tank for mounting. This Transformer has frequency ranging from 25 to 60 Hz. This Transformer has primary current ranging from 600 to 3000 amperes