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The Belimo LF24-SR is a versatile spring return actuator designed for controlling damper sections in technical building installations. The actuator is operated with a 2-10 V control signal and also provides a 2-10 V feedback signal to the controller or cascade control system. Based on an external measurement signal—such as from a sensor monitoring a relevant parameter like temperature, pressure, or air quality—a control signal is generated that instructs the Belimo motor to adjust the damper position. In addition to modulating control, the actuator also supports on/off, 3-point, and communication control via MP-Bus, making it suitable for both simple and complex building automation systems. In case of power failure, the damper automatically returns to the safe position using spring energy. The motor runtime can be adjusted between 75 and 300 seconds, and the spring return moves the damper back in less than 20 seconds. With a torque of 4 Nm, a standby power consumption of just 0.8 W, and an exceptionally low noise level of 36 dB(A), it is ideal for smaller damper assemblies in commercial and residential installations.
The actuator mounts directly onto the damper shaft using the supplied universal clamp ring, suitable for shaft diameters from 8 to 16 mm. The shaft must be at least 84 mm long and extend a minimum of 20 mm. An included anti-rotation device prevents the actuator from rotating along with the shaft. The direction of movement for both motor and spring return is set via the mounting orientation (L/R). The rotation angle is mechanically adjustable between 37% and up to a maximum of 95%. The actuator does not include manual override. Electrical connection is via a fixed 1-metre cable with four 0.75 mm² cores. The actuator is configurable via Belimo Assistant 2, maintenance-free, and suitable for modulating and communicative positioning of smaller damper sections in ventilation units, fan coil units, air handling units, and building automation systems in commercial and residential installations.
| Brand | Belimo |
| Category | Belimo damper actuators |
| GTIN | 7630498104916 |
| Manufacturer's item number | LF24-SR |
| Article number | 23010057 |
| Category code | 101 |
| Suitable for air accessory | Yes |
| Supply voltage | 24 V AC/DC |
| Control signal | 2 - 10 V |
| Energy consumption in operation | 2.5 W |
| Energy consumption at rest | 1 W |
| Model | Rotating |
| Regulation type on/off | No |
| Regulation type modulating | Yes |
| Regulation type splitrange | No |
| Connection cable length | 1 m |
| Transmission | With cogwheels |
| With direct mount top flange according to ISO 5211 | No |
| Return at zero supply voltage | Yes |
| Deactivated when closed | Yes |
| Automatic stroke recognition | No |
| Adjustable position feedback signal | No |
| Auxiliary contacts | No |
| Auxiliary contacts optional | Yes |
| End contacts | None |
| Adjustable operating range | No |
| With mechanical setting indicator | Yes |
| Suitable for manual operation | No |
| Operating time | 150 s |
| Torque | 4 Nm |
| Potential free switch contact | No |
| Self-adjusting travel length | No |
| Max. angle of rotation | 95 ° |
| With safety function | Yes |
| Degree of protection (NEMA) | 3 |
| Degree of protection (IP) | IP54 |
| Max. electric power input | 5 VA |
| Ambient temperature (min) | -30 °C |
| Ambient temperature (max) | 50 °C |
| Height | 85 mm |
| Width | 130 mm |
| Depth | 300 mm |
| Explosion-proof | No |
| Housing material | Plastic |
| Suitable for valve | No |
Item number: 23010052
Item number: 23010062
