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On-off, fail-safe control of dampers in HVAC systems.
Describes spring return, manual positioning, and brushless DC motor functionality.
Overview of AF series electrical operation, ASIC, and brushless DC motors.
How the brushless DC motor functions without brushes or commutators.
How the actuator protects against overload and stall conditions.
Explains Hall Effect sensors for precise motor positioning.
Requirements for transformers powering AF24 actuators, including VA rating and class 2.
Rules for powering multiple actuators from a single transformer.
Guidelines for powering multiple actuators using separate transformers.
Specifies maximum wire lengths based on gauge for AF actuators.
Recommendations for wire types and installation practices, including shielding.
Describes the actuator's initialization process upon power application.
The Belimo AF120 (-S) US and AF230 (-S) US are on-off, spring return, fail-safe actuators designed for controlling air dampers in HVAC systems. These devices are engineered for reliable operation, providing positive close-off on airtight dampers and ensuring fail-safe functionality through their spring return mechanism.
The primary function of these actuators is to provide on-off control for dampers. This control can be initiated by an auxiliary contact or a manual switch. The actuators are designed to mount directly to a damper shaft, accommodating diameters up to 1.05 inches using a universal clamp. For applications where direct coupling to the damper shaft is not feasible, a crankarm and various mounting brackets are available.
The AF series actuators utilize a brushless DC motor, which is controlled by an Application Specific Integrated Circuit (ASIC). This ASIC continuously monitors and controls the actuator's rotation, incorporating a digital rotation sensing function to prevent damage in stall conditions. This means the actuator can be stalled at any point in its rotation without requiring mechanical end switches, enhancing its durability and operational flexibility. The brushless DC motor technology also eliminates the need for brushes and commutators, which are common wear items in traditional DC motors, contributing to a maintenance-free design.
For overload protection, the ASIC constantly monitors the DC motor's rotation and stops pulses to the motor if a stall condition is detected. This allows the motor to remain energized and produce full rated torque, ensuring that dampers are fully closed and that blade seals are properly compressed.
The AF series actuators provide 95° of rotation and feature a graduated position indicator, displaying positions from 0° to 95°. The 0° position represents the spring return position. A unique manual positioning mechanism allows users to set the damper at any desired position within its 95° range. The actuators are shipped with a +5° preload (5° from full fail-safe) to automatically compress damper gaskets for tight shut-off. When power is applied, the manual mechanism is released, and the actuator attempts to close to the 0° position during normal control operations. The manual override can also be physically released using a supplied crank.
The AF120/230-S US versions include two built-in auxiliary switches (SPDT). These switches are useful for safety interfacing or signaling, such as fan start-up. One switch's function at the fail-safe position is fixed at +5°, while the other switch's function is adjustable between +25° and +85°.
General| Power Supply | 24 VAC/DC |
|---|---|
| Control Type | Modulating |
| Angle of Rotation | 90° |
| Mounting Type | Direct Mount |
| Protection Class | IP54 |
| Housing Material | Polyamide |
| Torque | 12 Nm |
| Power Consumption Holding | 1 W |
| Auxiliary Switch | SPDT |
| Temperature Range | -30 to 50 °C |
