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Belimo LF24-SR US
MSRP: $520.00
Price: $195.00
You Save: $325.00 (63 %)


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Belimo Part LF24-SR US

Torque min. 35 in-lb, for control of air dampers

Damper Actuator for HVAC Temperature Control

Valve Actuator for HVAC Temperature Control

For proportional modulation of dampers in HVAC systems. Actuator sizing should be done in accordance with the damper manufacturers specifications.

The actuator is mounted directly to a damper shaft from 3/8 up to 1/2 in diameter by means of its universal clamp, 1/2 shaft centered at delivery. For shafts up to 3/4 use K6-1 accessory. A crank arm and several mounting brackets are available for applications where the actuator cannot be direct coupled to the damper shaft.

The actuator operates in response to a 2 to 10 VDC, or with the addition of a 500W resistor, a 4 to 20 mA control input from an electronic controller or positioner. A 2 to 10 VDC feedback signal is provided for position indication or master-slave applications.

The LF series actuators provide true spring return operation for reliable fail-safe application and positive close-off on air tight dampers. The spring return system provides consistent torque to the damper with, and without, power applied to the actuator.

The LF series provides 95 of rotation and is provided with a graduated position indicator showing 0 to 95.

The LF24-SR (-S) US uses a brushless DC motor which is controlled by an Application Specific Integrated Circuit (ASIC) and a microprocessor. The microprocessor provides the intelligence to the ASIC to provide a constant rotation rate and to know the actuators exact fail-safe position. The ASIC monitors and controls the brushless DC motors rotation and provides a digital rotation sensing function to prevent damage to the actuator in a stall condition. The actuator may be stalled anywhere in its normal rotation without the need of mechanical end switches. Power consumption is reduced
in holding mode.

The LF24-SR-S US version is provided with one built-in auxiliary switch. This SPDT switch is provided for safety interfacing or signaling, for example, for fan start-up. The switching function is adjustable between 0 and 95. The auxiliary switch in the LF24-SR-S US is double insulated so an electrical ground in not necessary.
Technical Attributes
Product: LF24-SR-S US
Torque 35 in-lb [4 Nm]
Control Input 2-10 VDC
Input Impedance 100 k for 2 to 10 VDC (0.1 mA), 500 for 4 to 20 mA
Position Feedback 2-10 VDC Feedback, 0.5 mA max
Running Time (motor) 150 seconds, independent of load
Running Time (fail-safe) <25 sec @ -4F to +122F [-20C to +50C], <60 sec @ -22F [-30C]
Auxiliary Switch --- 
Power Supply 24 VAC 20%, 50/60 Hz, 24 VDC 10%
Power Consumption Running: 2.5 W; Holding: 1 W
Transformer Sizing 5 VA (Class 2 power source)
Electrical Connection Two 3 ft, 18 GA appliance cables with 1/2" conduit connectors
Overload Protection Electronic throughout 0 to 95 rotation
Shaft Diameter Standard: 3/8" to 1/2" round, centers on 1/2"
Angle of Rotation 95 (adjustable with mechanical end stop, 40 to 95)
Direction of Rotation (motor) Reversible with built-in switch
Direction of Rotation (fail-safe) Reversible with CW/CCW mounting
Position Indication Visual indicator, 0 to 95 (0 is spring return position)
Manual Override --
Humidity 5 to 95% RH non-condensing
Ambient Temperature -22F to +122F [-30C TO +50C]
Ambient Temperature (safety) --
Storage Temperature -40F to +176F [-40C TO +80C]
Noise Level < 30 db (A) motor, spring return 62 dB (A)
Housing Material zinc coated steel
Housing NEMA 2, IP54
Agency Listing cULus acc. To UL 873 and CAN/CSA C22.2 No. 24-93
Quality Standards ISO 9001
Weight 3.2 lbs (1.45 kg.)
Item Number: LF24-SR US
Manufacturer: Belimo
Manufacturer Part No: LF24-SR US

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