Siemens Burner Servo Motor SQM40.235A20

Product Details

The Siemens SQM40 and SQM41 series are electromotoric actuators designed for driving gas or air dampers, as well as oil control valves, on medium to large burners. These actuators are highly versatile, offering versions for both Linkageless (LMV) systems and Standalone Modulating systems. 1. SQM40 vs. SQM41 Series While they look nearly identical, the primary difference is the torque and rotation direction capability: Series Rotation Nominal Torque Max Torque SQM40 Clockwise (CW) $5$ Nm $10$ Nm SQM41 Counter-clockwise (CCW) $10$ Nm $15$ Nm 2. All Model Variants The SQM40 series is divided into three main control categories based on the internal electronics: A. Stepper Motor Versions (For LMV2/LMV3 Systems) These are controlled via the system's bus and offer $0.1^\circ$ precision. SQM40.244... SQM41.244... Key Detail: These do not have internal cams; the LMV controller handles all positioning electronically. B. Analog Versions (4-20 mA / 0-10 V) These include an integrated electronic module that allows for modulating control without a complex burner management system. SQM40.245... SQM41.245... Key Detail: Used for standalone industrial applications where a PLC or RWF55 temperature controller provides the setpoint. C. 3-Position Versions (Relay/Contact) Standard versions used for "Open/Stop/Close" logic or High/Low fire control. SQM40.241... SQM41.241... 3. Technical Specifications Parameter Specification Mains Voltage AC $230$ V or AC $110$ V (depending on version) Operating Voltage DC $24$ V (for Stepper versions via LMV) Running Time $5 \dots 30$ seconds (adjustable via controller) Protection Class IP54 (Optional IP66 with extra gaskets) Ambient Temp $-20\text{°C}$ to $+60\text{°C}$ Duty Cycle $100\%$ Shaft Diameter $10$ mm (Various ends: D-shape, Woodruff key, or Square) 4. Key Functional Features Double-Ended Shaft: The SQM40 often features a drive shaft extending from both the front and rear, allowing for flexible mounting or the addition of external potentiometers. Integrated Potentiometer: Analog versions usually include a $1 \text{ k}\Omega$ or $5 \text{ k}\Omega$ conductive plastic potentiometer for high-accuracy position feedback. Robust Housing: The body is made of die-cast aluminum, providing superior durability compared to the plastic SQN series. Adjustable Cams (Non-stepper models): Standard versions use mechanical cams similar to the SQN series but with higher-precision microswitches. 5. Wiring and Connections The SQM40 series uses RAST connectors or screw terminals depending on the variant. Stepper versions use the RAST2.5 system common to the LMV series, while standalone versions use standard PG cable glands. 6. Selection Tip When replacing an SQM40, pay close attention to the shaft end. Common types include: Woodruff Key (91): For heavy-duty industrial linkages. D-Shape (92): Standard flat-sided shaft for set-screws. Square (93): For specialized mechanical adapters.