For proportional modulation of dampers in HVAC systems. Actuator sizing should be done in accordance with the damper manufacturerÛªs specifications.
The actuator is mounted directly to a damper shaft up to 1.05Û in diameter by means of its universal clamp. 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 500ë© 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. Not to be used for a master-slave application.
The AFB and AFX series actuators provide true spring return operation for reliable failsafe application and positive close-off on air tight dampers. The spring return system provides constant torque to the damper with, and without, power applied to the actuator.
The AFB and AFX series provides 95å¡ of rotation and is provided with a graduated position indicator showing 0å¡ to 95å¡.
The AFB24-SR and AFX24-SR 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 actuatorÛªs exact fail-safe position. The ASIC monitors and controls the brushless DC motorÛªs 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.
The AFB24-SR-S and AFX24-SR-S versions are provided with two built-in auxiliary switches. These SPDT switches provide safety interfacing or signaling, for example, for fan start-up. The switching function at the fail-safe position is fixed at +10å¡, the other switch function is adjustable between +10å¡ to +90å¡. The AFB24-SR, AFB24-SR-S, AFX24-SR and AFX24-SR-S actuator is shipped at +5å¡ (5å¡ from full fail-safe) to provide automatic compression against damper gaskets for tight shut-off.