How to Select an Electric Actuator？

Choosing the right electric actuator is critical for ensuring the long-term stability of an automated control system. Generally, selection should be evaluated across four dimensions: mechanical parameters, electrical control, application environment, and safety protection.

First, determine the motion required by the equipment:

• Part-turn (90°): Rotation is typically 0 to 90°. Suitable for ball valves, butterfly valves, and dampers.

• Linear: Outputs linear thrust. Suitable for globe valves, diaphragm valves, and gate valves that require a push/pull motion.

• Multi-turn: Rotates continuously for multiple circles. Suitable for gate valves or globe valves that require multiple turns to open/close.

The core goal is to ensure the actuator has enough power to move and seal the valve effectively.

• Output Torque/Thrust: When selecting, the rated torque of the actuator should be 1.2 to 1.5 times the maximum operating torque of the valve. This safety margin accounts for pressure fluctuations or internal scaling/debris that might cause the valve to stick.

• Operating Time/Speed: Choose the speed based on process requirements. Quick-action requirements (like emergency shut-off) differ significantly from slow-regulating needs (to prevent water hammer effects).

This determines how the actuator "talks" to your control system (PLC/DCS):

• Working Voltage: Common options include AC 220V / 380V / 110V or DC 24V.

• Control Mode:

  • On-Off Type: Only two states: fully open or fully closed.

  • Modulating Type

• Feedback Signal

The working environment directly impacts the actuator's lifespan:

• Ingress Protection (IP Rating): For outdoor use, IP67 is the minimum recommendation.

• Explosion-proof Requirements: For chemical, oil, or gas industries, the actuator must have the appropriate explosion-proof certification (e.g., Ex d IIB T4).

• Ambient Temperature: Standard models usually handle -20℃ to +70℃. Extreme cold or high-heat environments require specialized builds.

• Fail-safe Position: Upon power loss, should the valve stay in place, go fully open, or fully closed? (Requires internal battery or supercapacitor).

• Manual Override: Whether a handwheel is equipped for manual operation during power outages or commissioning.

• Intelligent Features: Do you need an LCD display, Bluetooth commissioning, or bus communication (e.g., Modbus, Profibus)?