This motorized spring stored energy mechanism is adopted for high-speed automatic operation. The closing time is less than 1.5 seconds after sending the signal from a control unit. Tripping time is less than 100ms after sending the signal from the control unit. The closing spring is charged by a motor and discharged instantaneously. This mechanism can be operated by battery (24VDC) for emergency when the usual power supply is disconnected. The control unit supplied by Yaskawa can be used for local operation and has a provision for RTU and radio communication for remote control.