1.Product Model：LF24-SR 2.Product Use：For operating air dampers with a maximum cross - sectional area of approximately 0.8m2 to perform safety functions (such as frost protection, smoke protection, hygiene, etc.) 3.Part Number：877 0003 000 4.Document Number：03 - 2220 - 04 5.Release Time：February, 2022 2.Electrical Parameters 1.Power Supply：24 Vac ±20%, 50…60 Hz; 24 Vdc -10%, +20% 2.Power Consumption：2.5 W when opening, 1 W in the open state; 5 VA for wire sizing (Imax = 5.8 A within 5 ms) 3.Control Signal (X)：2…10 Vdc 4.Input Resistance：100 kΩ 5.Measuring Voltage (Y)：2…10 Vdc (max. 0.7 mA, corresponding to 0…100% stroke) 3.Mechanical Parameters 1.Torque：Actuator min. 4 Nm, Spring return min. 4 Nm 2.Angle of Rotation：Max. 95° (adjustable in the range of 37…100% using an additional limit stop ZDB - LF) 3.Running Time：Actuator 150 s; Spring return approximately 20 s at -20…+50 °C, max. 60 s at -30 °C 4.Direction of Rotation：Selectable via the L/R switch, and the spring's direction of rotation is selected by left or right mounting 5.Position Indication：Mechanical indication, selected by left or right mounting 6.Connection Cable：1.0 m, 4×0.75 mm² (AWG18) 4.Environmental Parameters 1.Ambient Humidity：In compliance with EN 60335 - 1 standard 2.Ambient Temperature：Operation -30…+50 °C; Storage -40…+80 °C 3.Sound Power Level：Actuator max. 30 dB(A); Spring return approximately 62 dB(A) 4.Protection Class：Class III (Safety extra - low voltage), Enclosure protection level IP 54 5.Service Life：At least 60,000 operations 6.Weight：1.4 kg 5.Compliance Standards：Complies with EN13463 - 1:09, 2014/35/EU, 2014/30/EU, 2011/65/EU standards (involving Low Voltage Directive LVD, Electromagnetic Compatibility EMC, RoHS2) 6.Operation and Installation 1.Installation Method：Mounted directly onto the damper spindle via a universal spindle clamp, with an anti - rotation strap for fixation 2.Control Method：Controlled by a 2…10 Vdc modulating signal. The actuator runs according to the control signal and stretches the return spring; when power is interrupted, the spring energy returns the damper to a safe position ≤ 0° 3.Pre - tension Setting：Pre - tensioned 5° at the factory, can be unlocked manually by a crank or electrically by connecting the power supply, and the actuator returns to a safe position ≤ 0° after unlocking 4.Overload Protection：The actuator is overload - proof, does not require limit switches, and stops automatically when reaching the end stops 7.Accessory Information：Refer to the specification sheet "Accessories Damper Actuators" (No. 003 - 2251) for accessory information