5 products in this product line
S Series Spring Return Fail-Safe Electric Actuators


Sun Yeh S series spring return electric valve actuators  (also called fail safe electric actuators) and tunnel damper valve actuator utilize spring-driven pinion and rack mechanism to provide torque ranges from 50N‧m to 360N‧m mechanical fail-safe quarter-turn electric actuators. When power is supplied, the spring mechanism is compressed to store energy for movement. Once the power is lost or removed, the controlled valve or damper will be driven to a fail-safe position (either Fail OPEN or fail Closed) in either clockwise (CW, standard) or counter clock wise (CCW, optional) rotation.

In addition to standard open/close (two-position) control, floating(except S-3600) and modulating control(except S-3600) are available for option per application requirements. The open/close control is equipped with a buffer to reduce damages caused by the water hammer which is resulting from sudden starting or stopping of flow.

A clutch-less manual override is an available option of our spring return electric actuators which provide manual operation when power outage, no clutch or brake is required to change from electrical control to manual operation. If you are interested in our spring return valve actuators, feel free to send an inquiry to us!

ModelTorqueMotor PowerWeightMounting Interface
Nmin‧lbStandardW / Manual OverrideFlange TypeOutput DriveDepth of Output Drive
KglbKglbISO 5211mminchmminch
S-500 50 445 50 27 37 60 82 F07 17 0.669 30 1.181
S-1300 130 1150 130 57 77 126 170 F10 22 0.866 41 1.614
S-2000 200 1770 130 93 131.5 205 290 F12 27 1.062 45 1.772
S-2600 260 2300 130 95 133.5 210 295 F12 27 1.062 45 1.772
S-3600 360 3185 130 103 152 228 336 F12 36 1.417 43 1.693
S series Fail Safe Electric Actuator