SQM21.18502 Siemens Actuator

Overview

The Siemens SQM21.18502 is a high-torque, reversible motorized actuator designed for the precise control of gas or air dampers and other flow control elements in industrial and commercial burner systems. As part of the SQM2 series, this heavy-duty actuator is engineered for use with burner controls and switching devices that feature changeover contacts. It utilizes a synchronous motor to drive a shaft through a geartrain, providing reliable positioning and consistent operation in high-demand combustion environments.

Features

• Reversible synchronous motor that is locking-proof to ensure operational safety
• Heavy-duty geartrain constructed with hardened steel shafts and nitrated gearwheels for extended service life
• Integrated cam stack with 5 adjustable auxiliary switches and 2 end switches for complex control sequences
• External position indicator allows for easy visual monitoring of the actuator’s status
• Die-cast aluminum housing with a heat-resistant, impact-proof plastic cover rated at IP54
• Manual adjustment capability via an enclosed hook spanner or tool for precise switching point setting
• Self-lubricating sinter-bronze bearings in the reduction gearing to eliminate the need for maintenance

Specifications

• Model: SQM21.18502
• Operating Voltage: AC 220 V to 240 V (+10% / -15%) at 50/60 Hz
• Nominal Torque: 20 Nm
• Starting Torque: 20 Nm
• Holding Torque: 12 Nm
• Running Time: 45 seconds for 90 degrees; 66 seconds for 130 degrees (at 50 Hz)
• Direction of Rotation: Clockwise (when facing the drive shaft)
• Drive Shaft Diameter: 12 mm
• Power Consumption: 9 VA
• Protection Rating: IP54 (DIN 40050)
• Operating Temperature: -20 C to +60 C

Applications

• Precise positioning of air and gas dampers in industrial burner systems
• Control of load-dependent fuel-to-air ratios in commercial boiler applications
• Integration with Siemens burner controls such as the LMV5 or LME series
• Automated HVAC systems requiring high-torque motorized actuation for flow control
• Combustion equipment where secondary auxiliary switches are necessary for safety interlocks or remote signaling