The Belimo GMX24-3 is a high-torque non-spring-return damper actuator delivering 360 in-lb [40 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 GMX platform for large commercial HVAC dampers.
Specifications sourced from the official Belimo GMX24-3 technical data sheet (rev 2025-10-06).
Overview
Belimo GM-Series actuators are high-torque non-spring-return drives for the largest 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 GMX24-3 produces 360 in-lb [40 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
- Large, high-torque commercial HVAC dampers (360 in-lb)
- Non-spring-return applications (no fail-safe required)
- Big outdoor-air, mixing-box and industrial dampers
Key Features
High 360 in-lb Torque
Belimo's largest non-spring-return class — drives big commercial and industrial dampers, direct-coupling to round or square damper shafts up to 1.05 in..
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.
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 | GMX24-3 |
| Actuator Type | Non-Spring-Return (Non Fail-Safe) Damper Actuator |
| Nominal Voltage | AC/DC 24 V |
| Nominal Frequency | 50/60 Hz |
| Power Consumption (Running) | 4 W |
| Transformer Sizing | 6 VA |
| Torque | 360 in-lb [40 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) | 150 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 | 18 AWG plenum cable, 3 ft [1 m], 1/2" NPT connector |
| Overload Protection | Electronic, full 0-95° rotation |
| Electrical Protection | Double insulated (Class 2) |
| Enclosure Rating | NEMA 2 / UL Type 2 |
| Ambient Temperature | -22 to 122°F [-30 to 50°C] |
| Agency Listing | cULus (UL60730-1A/-2-14, CAN/CSA) |
| Quality Standard | ISO 9001 |
| Plenum Rated | UL 2043 (suitable for air plenums) |
| Weight | 3.7 lb [1.7 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the GMX24-3, 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 GMX24-3?
The Belimo GMX24-3 is a high-torque non-spring-return (non-fail-safe) damper actuator for large commercial HVAC. It produces 360 in-lb [40 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 2.
Is the GMX24-3 a spring-return (fail-safe) actuator?
No. The GMX24-3 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 GMX24-3 provide?
It delivers 360 in-lb [40 Nm] of torque — Belimo's largest non-spring-return class, sized for big commercial and industrial dampers.
What shaft sizes does the GMX24-3 fit?
It direct-couples to round or square damper shafts up to 1.05 in. using its universal clamp (K-GM20). For jackshafts or off-shaft mounting, a crank arm and brackets (ZG-JSA-1, ZG-GMA) are available.
What control signal does the GMX24-3 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.
How do you manually position the GMX24-3?
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 GMX24-3 available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the GMX24-3. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Fail-Safe
- Torque:
- 360 in-lb
- Control Signal:
- On/Off
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 2
- Series:
- GM
