NFX24-SR N4 | Belimo | Damper ActuatorConfigurable, Damper Actuator, 90 in lbs [10 Nm], Spring return, AC DC 24 V, DC 2 10 V, NEMA 4X For 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 up to 1. 05 in diameter by means of its universal clamp. The actuator operates in response to a 2 to 10 VDC, with the addition of a 500? resistor, a 4 to 20 mA control input