The Belimo NMX24-3-F-T is a non-spring-return damper actuator delivering 90 in-lb [10 Nm] of torque with on/off and floating-point control on AC/DC 24 V power. It direct-couples to round or square damper shafts up to 1.05 in. with a universal clamp and holds its last position on loss of power (non-fail-safe, no spring return), making it part of Belimo's configurable NMX platform for large commercial HVAC dampers.
Specifications sourced from the official Belimo NMX24-3-F-T technical data sheet (rev 2026-03-18).
Overview
Belimo NM-Series actuators are non-spring-return drives for commercial HVAC control dampers — they position the damper under power and hold the last commanded position when power is removed (there is no spring-return fail-safe). The NMX24-3-F-T produces 90 in-lb [10 Nm] and mounts directly to round or square damper shafts up to 1.05 in. with its universal clamp (a crank arm and brackets are available for jackshaft and linkage applications); manual positioning uses an external push button. Two-position on/off and 3-wire floating-point control position the damper from a controller or switch.
Best for
- Commercial HVAC control dampers (90 in-lb)
- Non-spring-return applications (no fail-safe required)
- Outdoor-air, mixing-box and zone dampers
- Square-shaft dampers (form-fit 8x8 mm coupling)
- Installations that prefer screw-terminal wiring
Key Features
90 in-lb Torque
Sized for commercial HVAC dampers; uses a form-fit 8x8 mm square coupling.
Non-Spring-Return Design
Holds the last commanded position when power is removed (non-fail-safe). Lower cost and power draw than a spring-return where fail-safe is not required.
On/Off & Floating Point
Accepts two-position on/off or 3-wire floating-point control from a controller, relay or switch.
Form-Fit Square Coupling
A form-fit 8x8 mm coupling drives square damper shafts directly, without a separate clamp.
Push-Button Manual Override
An external push button declutches the gear train so you can position the damper by hand for setup or service.
cULus Listed
Double-insulated (Class 2), cULus listed and ISO 9001 built for long, maintenance-free service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | NMX24-3-F-T |
| Actuator Type | Non-Spring-Return (Non Fail-Safe) Damper Actuator |
| Nominal Voltage | AC/DC 24 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 2 W |
| Torque | 90 in-lb [10 Nm] (minimum) |
| Control Signal | On/Off and Floating Point (3-wire) |
| Shaft Range | Up to 1.05 in. [26.7 mm] via universal clamp; crank arm available |
| Angle of Rotation | 95° (adjustable mechanical stops) |
| Running Time (Motor) | 95 s / 90° — factory default; field-adjustable 35-150 s |
| Behavior on Power Loss | Holds last position (non-spring-return) |
| Manual Override | External push button (self-locking gear) |
| Direction of Motion | Selectable with 0/1 switch |
| Electrical Connection | Screw terminal strip (26-14 AWG) |
| Overload Protection | Electronic, full 0-95° rotation |
| Electrical Protection | Double insulated (Class 2) |
| Enclosure Rating | NEMA 1 / UL Type 1 |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Agency Listing | cULus (UL60730-1A/-2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Weight | 1.4 lb [0.63 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the NMX24-3-F-T, drawn from the actuator datasheet. All are stocked by ZOT Supply as an authorized Belimo distributor.
Mounting & Linkage
Electrical Add-Ons
Frequently Asked Questions
What is the Belimo NMX24-3-F-T?
The Belimo NMX24-3-F-T is a non-spring-return (non-fail-safe) damper actuator for commercial HVAC. It produces 90 in-lb [10 Nm] of torque, uses on/off and floating-point control on AC/DC 24 V power, and holds its last position on loss of power. Its housing is rated NEMA 1.
Is the NMX24-3-F-T a spring-return (fail-safe) actuator?
No. The NMX24-3-F-T is non-spring-return: on power loss it holds its last position rather than driving to a fail-safe position. For fail-safe operation choose a spring-return Belimo actuator (such as the EF-Series) instead.
How much torque does the NMX24-3-F-T provide?
It delivers 90 in-lb [10 Nm] of torque, sizing it for commercial HVAC dampers.
What shaft sizes does the NMX24-3-F-T fit?
It uses a form-fit 8x8 mm square coupling for square shafts. For jackshafts or off-shaft mounting, a crank arm and brackets (ZG-NMA, ZG-JSL) are available.
What control signal does the NMX24-3-F-T use?
It uses on/off and floating-point control. On/Off and 3-wire floating-point control are driven from a controller, relay or switch.
What does the -F suffix mean on the NMX24-3-F-T?
The -F denotes a form-fit 8x8 mm square coupling that drives square damper shafts directly, instead of the round-shaft universal clamp.
What does the -T in NMX24-3-F-T mean?
The -T denotes a screw-terminal strip for field wiring (26-14 AWG) in place of the pre-wired cable. The actuator is otherwise identical.
How do you manually position the NMX24-3-F-T?
Press the external manual-override push button to declutch the gear train, then turn the damper by hand for setup or service.
Is the Belimo NMX24-3-F-T available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the NMX24-3-F-T. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Fail-Safe
- Torque:
- 90 in-lb
- Control Signal:
- On/Off
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 1
- Series:
- NM
- Shaft Coupling:
- Form-Fit 8x8 mm
