Description
The Belimo EFB24-SR-S is a high-torque spring return damper actuator delivering 270 in-lb (30 Nm) for precise modulating airflow control in HVAC systems. It operates on AC/DC 24 V power and features integrated auxiliary switches for position indication and control sequencing.
Technical Specifications
| Condition |
New/Never Used Surplus |
| Brand |
Belimo |
| Category |
Actuators & Dampers |
| Part Number |
EFB24-SR-S |
| Subcategory |
Damper Actuators |
| Nominal Voltage |
AC/DC 24 V |
| Nominal Frequency |
50/60 Hz |
| Voltage Range |
AC 19.2…28.8 V / DC 21.6…28.8 V |
| Power Consumption (Operation) |
8 W |
| Power Consumption (Rest) |
4.5 W |
| Transformer Sizing |
14 VA |
| Control Signal |
2…10 V (4…20 mA with resistor) |
| Input Impedance |
100 kΩ (2…10 V), 500 Ω (4…20 mA) |
| Position Feedback |
2…10 V |
| Torque Output |
270 in-lb (30 Nm) |
| Angle of Rotation |
35…95°, adjustable |
| Running Time (Motor) |
95 s / 90° |
| Running Time (Fail-Safe) |
<20 s @ -20…50°C |
| Auxiliary Switches |
2x SPDT |
| Electrical Connection |
Dual 18 GA cables, 1 m, 1/2" NPT |
| Degree of Protection |
IP54 / NEMA 2 |
| Ambient Temperature |
-30…50°C |
| Weight |
11 lb (5.2 kg) |
Information About EFB24-SR-S
The EFB24-SR-S is part of Belimo’s EFB series of spring return damper actuators designed for demanding HVAC airflow control applications. It incorporates electronic overload protection throughout the full rotation range and a double-insulated design to support safe and reliable operation. The actuator includes two factory-installed auxiliary switches to provide accurate position indication and support interlocking or safety-related control logic. Reversible fail-safe direction, selectable motor rotation, and adjustable mechanical end stops offer flexibility during installation and commissioning.
Key Features
- Spring Return Fail-Safe Operation: Integrated spring mechanism ensures automatic return to a predefined safety position during power loss for reliable system protection.
- High Torque Performance: Delivers a constant 270 in-lb (30 Nm) torque suitable for large or high-pressure air damper applications.
- Modulating Control Capability: Accepts a 2…10 V control signal with optional 4…20 mA configuration for precise proportional airflow regulation.
- Dual Auxiliary SPDT Switches: Includes two adjustable switches for damper position indication, sequencing, and safety interlocks.
- Electronic Overload Protection: Protects internal components throughout the full 0…95° rotation range against mechanical obstruction or overload.
- Manual Override Function: Supplied hex crank allows manual damper positioning during commissioning, testing, or maintenance.
- Adjustable Mechanical End Stops: Enable precise limitation of rotation angle to match damper requirements.
The EFB24-SR-S delivers the reliability and precision required for modulating airflow control with dependable fail-safe operation in HVAC systems.
