Description
Belimo NKQB24-SR Electronic Fail-Safe Actuator Overview
The Belimo NKQB24-SR is a high-performance electronic fail-safe damper actuator engineered for reliable, precise control in commercial HVAC and building automation applications. Designed to deliver consistent torque and responsive positioning, this actuator ensures safe, automatic return to a defined fail-safe position upon loss of power — a critical feature for life-safety and energy management systems.
Key Features
- Electronic fail-safe operation — automatically returns to fail-safe position on power loss
- 54 in-lb (6 Nm) torque output for dependable damper control
- Proportional 2–10 Vdc control signal for precise modulating operation
- Dual voltage compatibility: 24 Vac and 24 Vdc power supply
- Fast 4-second fail-safe return time for rapid response in critical applications
- Compact, robust housing suitable for demanding commercial environments
- Direct-coupled design for easy installation without crank arms or linkages
Electrical Specifications
- Power Supply: 24 Vac / 24 Vdc
- Control Signal: 2–10 Vdc (proportional)
- Fail-Safe Return Time: 4 seconds
Mechanical Specifications
- Torque: 54 in-lb
- Actuator Type: Electronic Fail-Safe, Direct-Coupled
- Application: Damper actuator for HVAC air handling and building automation systems
Applications
The NKQB24-SR is ideal for use in variable air volume (VAV) systems, air handling units (AHUs), economizers, and other commercial HVAC damper control applications where fail-safe positioning and proportional modulation are required. Its compatibility with 24 Vac and 24 Vdc systems makes it a versatile choice for new installations and retrofits alike.
Why Choose Belimo?
Belimo is a globally recognized leader in actuator and valve technology for the HVAC industry, known for precision engineering, long service life, and ease of installation. The NKQB24-SR upholds that legacy with dependable fail-safe performance and a straightforward direct-couple mounting system.







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