4 products in this product line
OM Quarter Turn Electric Actuator


Sun Yeh S series spring return electric valve actuators utilizes spring driven pinion and rack mechanism to provide torque ranges from 50Nm to 260Nm 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 fail safe position (either Fail OPEN or fail Closed) in either clock wise (CW, standard) or counter clock-wise (CCW, optional) rotation.

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

A clutch-less manual override is available option to provide manual operation when power outage, no clutch or brake is required to change from electrical control to manual operation. With this outstanding design, spring return valve actuators are patented in Taiwan, USA, China, and Japan.

ModelMax TorquePower
WeightStandard Mounting
N.mlb.inStandardW / Manual 
Mounting FlangeShaftDepth Of Shaft
KglbKglb(ISO 5211)mminchmminch
S-500 50 443 50 27 60 37 82 F07 17 0.67 30 1.18
S-1300 130 1151 130 57 126 74 163 F10 22 0.87 39 1.54
S-2000 200 1771 130 95 209 135 298 F12 27 1.06 45 1.77
S-2600 260 2302 130 95 209 135 298 F12 N/27 1.06 45 1.77
S series