Damper actuators help in adjusting the flow of air in an HVAC system. They work for assessing floating-point control of your home’s heating or cooling unit. Ideally, the size of every actuator should be the same as the damper. Manufacturers go through a lot to meet the specification standards of damper actuators. Even a small difference in size may hamper the performance of your HVAC system.


Structure of damper actuators


Damper shafts usually come with a diameter of 1.05″ or more. The actuator stands on top of the damper shaft with the help of a self-centered universal clamp. It also comes with a crank arm and various mounting brackets. Sometimes the actuator cannot work together with the damper shaft. In such cases, the mounting brackets and crank arm come together to support the actuator in areas where it cannot meet with the shaft’s diameter.


The function of damper actuators


Belimo actuators don’t require any limit switches compared to traditional damper actuators. Instead, they stay protected electronically against any overload. Modern-day damper actuators come with anti-rotation straps that prevent the actuator from lateral movement.


In many of these units, the actuators offer a 95-degree rotation. This allows the visual indicator to show the precise position of the actuator. When the actuator reaches the damper, it stops automatically. You can manually disengage the gears by pressing the actuator cover button.


Since the actuator uses a sensorless brushless DC motor, it can control the Application Specific Integrated Circuit. The Application Specific Integrated Circuit, in turn, controls and monitors the rotation of the actuator and also provides a digital rotation sensing function. This function prevents any damage to the actuator, thus keeping the HVAC system safe. The digital rotation sensor also reduces the power consumption in holding mode so that the actuator doesn’t override the damper.


The function of an auxiliary switch


In many damper actuators, you will see an in-built auxiliary switch. This is the SPDT switch that offers safety interfacing and signals the actuator to stay within the limits of the damper. Additionally, it also signals the on or off function of the HVAC’s fan. Like the actuator, the auxiliary switch is also adjustable. You can adjust its movement within 0 and 95 degrees. This switch also comes with double insulation, so you don’t need to arrange for electrical ground connection separately.


Some damper actuators also come with additional auxiliary switches. These work as feedback potentiometers. They remain attached to the actuator body for both signaling and switching purposes.


You need to analyze your HVAC system’s specifications before selecting a damper actuator. Always keep a few parameters in mind, such as supply voltage, torque, required range of output, and operating voltage. If you require a damper actuator for a single force, choose a unit where the moment of force creates a cross-product of its vector from the application point. For multiple forces, the moment of force becomes the vector sum of all the torque values. But in both cases, make sure to keep the supply voltage in its nominal range to allow the damper actuator to function properly.


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