The Belimo LMX24-SR-T is a compact non-spring-return damper actuator delivering 45 in-lb [5 Nm] of torque with modulating 2-10 VDC control on AC/DC 24 V power. It direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp) and is non-fail-safe, with no spring return, making it part of Belimo's configurable LMX platform for small to mid-size commercial HVAC dampers. Field wiring is via a screw-terminal strip (26-14 AWG).
Specifications sourced from the official Belimo LMX24-SR-T technical data sheet (rev 2025-10-06).
Overview
Belimo LM-Series actuators are compact non-spring-return drives for small and mid-size commercial HVAC dampers — they position the damper under power and have no spring-return fail-safe function. The LMX24-SR-T produces 45 in-lb [5 Nm] and mounts directly to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp). A 2-10 VDC (or 4-20 mA with the ZG-R01 resistor) signal modulates the damper, with 2-10 VDC position feedback.
Best for
- Modulating damper control without fail-safe return
- Small to mid-size damper and louver positioning (45 in-lb)
- Direct shaft mount, 1/4-5/8 in. (to 3/4 in. with accessory clamp)
- Installations that prefer screw-terminal wiring
Key Features
Non-Spring-Return Design
No fail-safe spring return. Belimo does not publish a defined position on loss of power for this model; specify a spring-return actuator where a fail-safe position is required.
45 in-lb Torque
Sized for small and mid-size dampers; direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp).
Modulating 2-10 VDC
Accepts a 2-10 VDC (or 4-20 mA with ZG-R01) signal with 2-10 VDC position feedback.
Screw-Terminal Wiring
Field wiring lands on a screw-terminal strip (26-14 AWG) instead of a pre-wired cable.
cULus Listed & Quiet
cULus listed, ISO 9001 built, UL 2043 plenum-rated for long, maintenance-free service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Belimo |
| Part Number | LMX24-SR-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) | 1.5 W |
| Transformer Sizing | 3 VA |
| Torque | 45 in-lb [5 Nm] |
| Control Signal | Modulating |
| Operating Range (Y) | 2-10 VDC (4-20 mA with ZG-R01 resistor) |
| Position Feedback (U) | 2-10 VDC (max. 0.5 mA) |
| Shaft Range | 1/4 in. to 5/8 in. (to 3/4 in. with accessory clamp) |
| Angle of Rotation | Max. 95° (adjustable mechanical stop) |
| Running Time (Motor) | 95 s / 90° |
| Running Time Note | constant, independent of load |
| Variable Running Time | 35, 45, 60, 150 s |
| Behavior on Power Loss | Non fail-safe — no fail-safe spring return function |
| Manual Override | External push button |
| Direction of Motion | Selectable with 0/1 switch |
| Electrical Connection | Screw terminal strip (26-14 AWG) |
| Overload Protection | Electronic, full 0-95° rotation |
| Power Source | UL Class 2 Supply |
| 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 |
| Plenum Rated | UL 2043 (suitable for air plenums) |
| Weight | 0.76 lb [0.35 kg] |
| Warranty | 5 Years |
Documentation
Related Products
Accessories & Mounting
Common Belimo accessories for mounting, linkage, signaling and powering the LMX24-SR-T, drawn from the actuator datasheet. All are stocked by ZOT Supply as an authorized Belimo distributor.
Mounting & Linkage
Electrical Add-Ons
Enclosures & Weather Shields
Frequently Asked Questions
What is the Belimo LMX24-SR-T?
The Belimo LMX24-SR-T is a compact non-spring-return (non-fail-safe) damper actuator for commercial HVAC. It produces 45 in-lb [5 Nm] of torque, uses modulating 2-10 VDC control on AC/DC 24 V power. It is non-fail-safe: Belimo does not publish a defined position on loss of power for this model. Its housing is rated NEMA 1.
Is the LMX24-SR-T a spring-return (fail-safe) actuator?
No. The LMX24-SR-T is non-spring-return: it has no fail-safe spring, so it will not drive to a predetermined position when power is lost. Where a defined position on power loss is required, select a spring-return actuator sized to the damper manufacturer's specifications.
What happens to the LMX24-SR-T when power is lost?
There is no spring return, so the actuator does not drive itself to a fail-safe position. Belimo's datasheet for this model does not publish a defined power-loss position; if your sequence depends on a specific position during a power failure, specify a spring-return actuator.
What shaft sizes does the LMX24-SR-T fit?
It direct-couples to round or square damper shafts from 1/4 in. to 5/8 in. (up to 3/4 in. with an accessory clamp) using its universal clamp.
What control signal does the LMX24-SR-T 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.
What is the running time of the LMX24-SR-T?
Motor running time is 95 s / 90°. Belimo also publishes variable running-time values of 35, 45, 60, 150 s.
What does the -T in LMX24-SR-T mean?
The -T denotes a screw-terminal strip for field wiring (26-14 AWG) in place of the pre-wired cable and conduit connector. Other specifications are not identical — LMX24-SR-T and LMX24-SR differ on enclosure rating NEMA 1 vs NEMA 2; weight 0.76 lb vs 0.91 lb. Verify against the exact -T model datasheet before substituting.
What is the difference between the Belimo LMX24-SR-T and the LMB24-SR-T?
Both are non-spring-return actuators of the same torque class. Their published specifications are not identical: LMX24-SR-T and LMB24-SR-T differ on weight 0.76 lb vs 1.0 lb. LMX24-SR-T additionally publishes a variable running time of 35, 45, 60, 150 s; LMB24-SR-T does not publish this field. Both datasheets state the same electrical connection. Verify the exact control, running time, electrical, enclosure and mounting requirements before substituting one for the other.
Is the Belimo LMX24-SR-T available from an authorized Belimo distributor?
Yes. ZOT Supply is an authorized Belimo distributor and carries the LMX24-SR-T. Every unit ships factory new with Belimo's full 5-year warranty and application support.
- Actuator Type:
- Non-Fail-Safe
- Torque:
- 45 in-lb
- Control Signal:
- Modulating
- Voltage:
- 24 VAC/DC
- Auxiliary Switch:
- No
- Series:
- LM
- Feedback Signal:
- 2-10 VDC
