Belimo NMB24-SR Motor Actuator

The Belimo NMB24-SR is a high-performance non-spring return actuator designed specifically for the proportional modulation of dampers in commercial HVAC systems. Delivering a robust 90 in-lb torque, this direct-coupled actuator is capable of controlling damper surfaces up to 22 square feet without the need for complex linkages. It operates on a universal 24VAC/DC power supply and responds to a standard 2...10 VDC modulating signal. For systems requiring current-based control, the unit can be easily adapted for 4 to 20 mA input with the addition of a 500 Ω resistor.

Engineered for longevity, the NMB24-SR features a sensorless brushless DC motor managed by an Application Specific Integrated Circuit (ASIC). This advanced internal logic provides digital rotation sensing (DRS) to protect the motor from damage during stall conditions, eliminating the need for external limit switches. The NEMA 2 rated housing and 18 AWG plenum-rated cable ensure reliable integration into building automation environments. Technicians can utilize the external push-button for manual override and a selectable direction switch to streamline field commissioning and testing.

• High Torque Output: Provides 90 in-lb [10 Nm] of motor torque to handle large damper surfaces.
• Brushless DC Technology: Uses a sensorless motor for maintenance-free operation and electronic overload protection.
• Flexible Control: Supports 2...10 VDC or 4...20 mA (with resistor) control signals and provides a 2...10 VDC feedback signal.
• Simple Installation: Direct-coupled universal clamp fits shafts from 1/4" to 1.05" diameter for rapid mounting.
• Energy Efficient: Features a low power consumption of only 0.4 W in the rest position and 1.5 W during operation.

Common Questions

Can the NMB24-SR be used in 4-20 mA control loops?
Yes, by adding a ZG-R01 500 Ω resistor, the actuator can accept a 4...20 mA signal from your controller.

What happens if the damper jams or stalls?
The integrated ASIC monitors motor rotation and provides electronic overload protection, stopping the motor automatically without requiring limit switches.

Is this a fail-safe actuator?
No, the NMB24-SR is a non-spring return (non-fail-safe) actuator. It will maintain its last position upon loss of power unless manually overridden.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.