Siemens Thermax Boiler Burner Servomotor

Product Details

Siemens burner servomotors (actuators) are the industry standard for controlling the air-to-fuel ratio in combustion systems. They are categorized into two main technologies: Electromechanical (SQN) for traditional linkage-based burners and Electronic/Stepper (SQM) for modern linkageless (LMV) systems. 1. SQN Series (Electromechanical) The SQN series uses reversible synchronous motors with adjustable mechanical cams.1 They are used with controllers like the LME, LMO, or LGB.2 +1   Series Torque Running Time (90∘) Key Features SQN30/31 $1.0 - 3.0$ Nm $4.5 - 30$ s Compact, clockwise (SQN30) or CCW (SQN31) rotation. SQN70/71 $1.5 - 2.5$ Nm $4 - 30$ s High-duty cycles, common in Riello and Weishaupt burners. SQN90/91 $0.8 - 3.0$ Nm $4 - 24$ s Reversible, often used for small gas/oil burners. Details: Adjustment: Uses color-coded cams (Red: Max, Blue: Min, Orange: Ignition). Manual Release: Features a clutch to disengage gears for manual commissioning. Protection: Typically IP40. 2. SQM Series (Electronic & Stepper) The SQM series is more robust, offering higher torque and precision. They are divided into "Analog" (cams/potentiometers) and "Digital" (CAN bus stepper). A. Analog/Modulating Models (SQM10, 20, 50) Used for standalone modulating control (e.g., with RWF55) or traditional linkages. SQM10/20: Up to $20$ Nm torque. Aluminum housing. SQM50/53/56: The industrial workhorses. Torque up to $40$ Nm. $100\%$ duty cycle. B. Linkageless Stepper Models (SQM33, 45, 48, 91) Specifically for LMV2/3 and LMV5 systems. No mechanical cams; positioning is handled via CAN bus. Model Torque Controller Feedback Type SQM33 Up to $3$ Nm LMV2 / LMV3 Stepper/Internal SQM45 $3$ Nm LMV5 Hall Sensor (B9 versions) SQM48 $20 - 35$ Nm LMV5 Hall Sensor (B9 versions) SQM91 Up to $60$ Nm LMV5 High-torque Stepper 3. Technical Comparison: SQN vs. SQM Specification SQN Series SQM Series Drive Shaft Plastic or light metal ($8-10$mm) Steel ($10, 12, 14$mm) Housing Plastic / Composite Die-cast Aluminum Positioning Mechanical Cams Digital (CAN) or Potentiometer Precision $\approx 1^\circ$ $0.1^\circ$ (Stepper models) IP Rating IP40 IP54 / IP66 4. Key Selection Factors When choosing or replacing a Siemens servomotor, you must verify: Direction of Rotation: Clockwise (e.g., SQN30) vs. Counter-clockwise (e.g., SQN31). Running Time: $90^\circ$ travel must match the burner controller's sequence (e.g., $12$s vs $30$s). Shaft Type: Square, D-shape, or Woodruff key. Interface: 3-position relay (SQN) vs. CAN bus (SQM33/45/48) vs. $4-20$ mA (SQM40/41).