SQM40.255R11 Siemens Actuator

Overview

The Siemens SQM40.255R11 is a high-precision electromotoric rotary actuator designed for the accurate positioning of flow control valves, butterfly valves, and dampers in industrial and commercial burner systems. Engineered for medium to higher capacity oil and gas burners, this actuator provides load-dependent control of gas, oil, and combustion air. It features a robust NEMA 4 weatherproof enclosure, allowing for mounting in any orientation without the need for additional shielding, and utilizes a synchronous motor for reliable, long-term operation in thermal process plants.

Features

• Precise modulation with over 100 steps of resolution to ensure stable set points without hunting or oscillation
• Internal position indication and easily adjustable cam switches for setting high and low fire conditions
• Drive shaft disengagement clutch allows for manual adjustment and positioning during setup
• Durable construction with a die-cast aluminum lower housing and impact-proof, heat-resistant plastic cover
• NEMA 4/IP66 rated enclosure ensures protection against dust and water in demanding environments
• Electronic version supporting analog control signals with integrated zero and span adjustments

Specifications

• Model: SQM40.255R11
• Torque: 90 in-lb (10 Nm)
• Running Time: 25 seconds for 90 degree rotation (at 60 Hz)
• Control Signal: 4-20 mA input with 135 Ohm potentiometer feedback
• Operating Voltage: 110V AC (50/60 Hz)
• Rotation Direction: Counter-clockwise (CCW)
• Shaft Type: 10 mm D-shaft
• Auxiliary Switches: 4 internal switches (including independent Form-C aux switch)
• Temperature Range: -5 F to 140 F (-20 C to 60 C)
• Approvals: UL-listed, CSA, CE, and GL marine approval

Applications

• Load-dependent control of combustion air and fuel flow in industrial burners
• Positioning of butterfly valves and oil pressure controllers in thermal process plants
• Precise damper control in HVAC systems and large-scale boiler applications
• Integration with 3-position or modulating controllers and burner management systems
• Direct coupling or linkage-based control for multiple air/fuel adjustment points