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Belimo Spring Return Actuator

Belimo Damper Actuator - Spring, 180in-lb, MFT, 24V


Spring Return
180 in-lb [20 Nm]
24 VAC

Usually Ships: Call for Ship Date

Availability: In stock



For proportional modulation of dampers and control valves in HVAC systems. The AFB24-MFT, AFX24-MFT provides mechanical spring return operation for reliable failsafe application.

graduated position indicator showing 0° to 95°. The actuator will synchronize the 0° mechanical stop or the physical damper or valve mechanical stop and use this point for its zero position during normal control operations. A unique manual override allows the setting of any actuator position within its 95° of rotation with no power applied. This mechanism can be released physically by the use of a crank supplied with the actuator. When power is applied the manual override is released and the actuator drives toward the fail-safe position.

The actuator 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 actuator’s exact position. The ASIC monitors and controls the brushless DC motor’s rotation and provides a Digital Rotation Sensing (DRS) function to prevent damage to the actuator in a stall condition. The position feedback signal is generated without the need for mechanical feedback potentiometers using DRS. The actuator may be stalled anywhere in its normal rotation without the need of mechanical end switches.

The AFB24-MFT, AFX24-MFT is mounted directly to control shafts up to 1.05" diameter by means of its universal clamp and anti-rotation bracket. A crank arm and several mounting brackets are available for damper applications where the actuator cannot be direct coupled to the damper shaft. The spring return system provides minimum specified torque to the application during a power interruption. The AFB24-MFT, AFX24-MFT actuator is shipped at +5° (5° from full fail-safe) to provide automatic compression against damper gaskets for tight shut-off.

Fail-Safe Spring Return
Torque 180 in-lb [20 Nm]
Control Input Proportional/MFT
Input Impedance 100 k Ω for 2 to 10 VDC (0.1 mA), 500 Ω for 4 to 20 mA, 1500 Ω for PWM, floating point and On/Off
Position Feedback 2 to 10 VDC, 0.5 mA max, VDC variable
Running Time (motor) 150 seconds (default), variable (70 to 220 seconds)
Running Time (fail-safe) < 20 seconds @ -4°F to +122°F [-20°C to +50°C], < 60 sec @ -22°F [-30°C]
Auxiliary Switch --
Power Supply 24 VAC ± 20%, 50/60 Hz, 24 VDC + 20% / -10%
Power Consumption 7.5 W,3 W
Transformer Sizing 10 VA (class 2 power source)
Electrical Connection 3 ft [1m], 10 ft [3m] or 16 ft [5m] 18 GA appliance or plenum cables, with or without 1/2" conduit connector
Overload Protection electronic throughout 0 to 95° rotation
Shaft Diameter Standard: 1/2" to 1.05" round, centers on 1/2" and 3/4" with insert, 1.05" without insert
Angle of Rotation 95° (adjustable with mechanical end stop, 35 to 95°)
Direction of Rotation (motor) reversible with built-in switch
Direction of Rotation (fail-safe) reversible with CW/CCW mounting
Position Indication visual indicator, 0° to 95° (0° is full spring return position)
Manual Override 5 mm hex crank (3/16" Allen), supplied
Humidity max. 95% RH non-condensing
Ambient Temperature -22°F to +122°F [-30°C to +50°C]
Ambient Temperature (safety) --
Storage Temperature -40°F to +176°F [-40°C to +80°C]
Noise Level <40 dB (A) motor @ 150 seconds, run time dependent, <62dB (A) spring return
Housing Material zinc coated metal and plastic casing
Housing NEMA 2, IP54, UL enclosure type 2
Agency Listing cULus acc. To UL60730-1A/-2-14, CAN/CSA E60730-1:02, CE acc. To 2004/108/EC & 2006/95/EC
Quality Standards ISO 9001
Weight 4.6 lbs (2.1 kg)

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