GTW88 series intelligent air breaker is applicable for distribution network of AC 50Hz , rated voltage of 400V and 690V , and rated current of 630A～3200A , to distribute electric energy protection circuit and prevent power equipments from harm of overload , under-voltage , short circuit and single-phase earth etc. Provided with intelligent protecting function and precise selective protection , breaker can enhance the dependability of power supply and avoid unwanted power cut.