| 摘要 |
Electric-powered actuating device usable for the positioning control of valves and the like, featuring a motor, mechanical and spring means capable of driving said valve or other attached devices into a predetermined safety position in case of electrical signal or power failure; said actuating device having electrical amplifying means capable of providing pulsed current to drive said motor in one direction, a direct current to hold the motor in a selected position or, no power, to allow the mechanical and spring means to reverse the motor direction. |
