Siemens SQM Series

Series Overview

The Siemens SQM Series consists of industrial servo actuators designed for precise positioning control in combustion systems.

These actuators regulate air dampers, fuel valves, and ratio control mechanisms to ensure stable and efficient burner operation across different load conditions.

Unlike simple on/off motors, SQM actuators provide controlled rotational movement with defined torque characteristics, enabling accurate air-fuel ratio adjustment in modulating and multi-stage burner systems.

Role in Combustion Control Architecture

In a complete industrial combustion system:

• The burner control unit manages sequencing and safety logic
• The actuator executes positioning commands
• The damper or fuel valve adjusts airflow or fuel supply

The SQM Series performs the critical mechanical adjustment required to maintain optimal combustion performance during ignition, modulation, and shutdown phases.

Typical Applications

SQM Series servo actuators are widely applied in:

• Industrial gas burners
• Oil-fired burners
• Dual-fuel combustion systems
• Boiler air control assemblies
• Ratio control systems
• Process heating equipment

They are commonly integrated into systems requiring continuous modulation or staged combustion control.

Core Functional Characteristics

All SQM Series actuators share the following capabilities:

• Precision rotational positioning: Accurate control of damper angles.
• Defined torque output classes: Ranging from light to heavy-duty loads.
• Adjustable switching cams: Flexible configuration of limit positions.
• Reliable industrial-grade construction: Durable housing for plant environments.
• Continuous duty operation: Designed for modulating control cycles.

Differentiation Within the SQM Series

Although all SQM actuators provide servo positioning, variations exist in:

• Torque rating (Nm)
• Rotation angle range
• Operating voltage
• Feedback configuration (potentiometer type)
• Application classification

Different SQM models are selected depending on burner capacity, damper size, and mechanical load requirements.

Selection Guide

When selecting an SQM actuator, consider:

1. Required Torque: Ensure the actuator can move the damper or valve load.
2. Rotation Angle: Verify the travel range (e.g., 90° or 135°).
3. Electrical Supply: Check voltage (110V / 220V) and control signal.
4. Integration: Confirm compatibility with the burner control unit (LME/LMV).

Integration in Modulating Burner Systems

In modulating burners, the SQM Series enables dynamic airflow and fuel adjustment in response to load demand. This ensures:

• Optimized combustion efficiency
• Reduced fuel consumption
• Lower emission levels
• Stable flame across load variations

The actuator plays a critical role in maintaining consistent air-fuel ratio balance.