| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve actuator for closing or opening a valve by using the resilience of a spiral spring wound up by the drive of a DC motor for rotating the rotor of the DC motor in emergency to generate electric power which energizes a reversible DC motor for driving the valve. SOLUTION: The reversible DC motor for driving the valve to be opened/closed and the DC motor for winding up the spiral spring are provided in a casing. The spiral spring wound up by the DC motor is rewound during deenergization for rotating the rotor of the DC motor to generate electric power which energizes the reversible DC motor. Thereby, the valve is closed or opened. COPYRIGHT: (C)2004,JPO
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