SQM40.261A21 Siemens Actuator

Overview

The Siemens SQM40.261A21 is a high-precision electromotoric actuator designed for the accurate positioning of flow control valves, butterfly valves, dampers, and other components requiring rotary motion. This counterclockwise-rotating actuator is specifically engineered for load-dependent control of gas, oil, and combustion air in medium to high-capacity burners and thermal process plants. Built with a robust die-cast aluminum lower housing and an impact-proof plastic cover, it provides reliable performance for both industrial and commercial combustion applications.

Features

• High-precision synchronous motor ensures consistent running times and torque
• Manual shaft disengagement via a coupling pin allows for easy alignment during installation
• Adjustable cams with integrated scales enable precise setting of switching points
• Maintenance-free gear train and bearings for long-term service life
• Internal position indication for real-time monitoring of rotation angle
• NEMA 4 rated weatherproof enclosure (on specific versions) suitable for demanding environments
• Electronic self-checking and high repeatability for safety-critical burner operations

Specifications

• Model: SQM40.261A21
• Direction of Rotation: Counterclockwise
• Rated Torque: 10 Nm (approx. 90 in-lb)
• Running Time: 30 seconds for 90 degrees (at 50 Hz)
• Operating Voltage: AC 230 V (+10% / -15%)
• Frequency: 50/60 Hz
• Shaft Type: 10 mm diameter with Woodruff key
• Potentiometer: Single potentiometer included
• Rotation Angle: Adjustable up to 90 degrees
• Protection Rating: IP54 (standard) or IP66/NEMA 4 depending on configuration
• Operating Temperature: -20 C to +60 C

Applications

• Load-dependent control of air and gas dampers in industrial burners
• Positioning of oil pressure controllers and fuel volume control valves
• Integration with 3-position or modulating controllers (e.g., 4-20 mA) for thermal process plants
• Use in medium to large capacity oil and gas burner systems
• HVAC and boiler system air-to-fuel ratio control for optimized combustion efficiency