| 摘要 |
PROBLEM TO BE SOLVED: To provide an actuator for a valve having a lower possibility of failures by holding energization of an excitation brake for a set time in a case of an instantaneous power failure and preventing a power spring from being unwound and wound to elongate life. SOLUTION: In the actuator for an emergency-open/close type valve wherein the power spring is wound to hold a pressure accumulated state by the excitation brake simultaneously when the valve is closed or opened by driving a motor and the valve is closed or opened by a restoration force of the power spring by a shut-off of power, an electric double-layered capacitor is provided in a motor drive circuit, a locked state of the excitation brake holding the pressure accumulated state of the spring is prevented from being unlocked due to the instantaneous power failure by discharge of the capacitor. COPYRIGHT: (C)2004,JPO
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