The Belimo GM24SR.1B is a high-torque non-spring-return damper actuator delivering 360 in-lb [40 Nm] of torque with modulating 2-10 VDC 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 a Belimo GM-Series actuator for large commercial HVAC dampers.
Specifications sourced from the official Belimo GM24SR.1B technical data sheet (rev 2026-06-05).
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 GM24SR.1B 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. A 2-10 VDC signal (or 4-20 mA with the ZG-R01 resistor) modulates the damper, with 2-10 VDC position feedback.
Best for
- Modulating control of large 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.
Modulating 2-10 VDC
Accepts a 2-10 VDC (or 4-20 mA with ZG-R01) signal with 2-10 VDC position feedback.
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 | GM24SR.1B |
| 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 |
| Transformer Sizing | 5 VA |
| Torque | 360 in-lb [40 Nm] (minimum) |
| Control Signal | Modulating |
| Operating Range (Y) | 2-10 VDC (4-20 mA with ZG-R01 resistor) |
| Position Feedback (U) | 2-10 VDC (max. 1 mA) |
| 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° |
| 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 | 3.5 lb [1.6 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the GM24SR.1B, 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 GM24SR.1B?
The Belimo GM24SR.1B 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 modulating 2-10 VDC control on AC/DC 24 V power, and holds its last position on loss of power. Its housing is rated NEMA 2.
Is the GM24SR.1B a spring-return (fail-safe) actuator?
No. The GM24SR.1B 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 GM24SR.1B 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 GM24SR.1B 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 GM24SR.1B use?
It uses modulating 2-10 VDC control. The 2-10 VDC input also accepts 4-20 mA with the ZG-R01 resistor and provides 2-10 VDC feedback.
Is GM24SR.1B a current Belimo part number?
The GM24SR.1B uses Belimo's legacy GM type-reference numbering. It remains available and is functionally a 360 in-lb non-spring-return GM actuator; ZOT Supply can help cross-reference it to the current GMB/GMX equivalent if needed.
How do you manually position the GM24SR.1B?
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 GM24SR.1B available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the GM24SR.1B. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Spring-Return
- Torque:
- 360 in-lb
- Control Signal:
- Modulating
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Enclosure:
- NEMA 2
- Series:
- GMB
- Feedback Signal:
- 2-10 VDC
