The Belimo AF24-MFT S US actuator is designed for proportional modulation of dampers and control valves in HVAC systems, providing mechanical spring return operation for reliable fail-safe application. Also includes a torque minimum of 133 in-lb, control 2 to 10 VDC, and feedback 2 to 10 VDC.
The AF24-MFT S US uses a brushless DC motor which is controlled by an 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 then monitors and controls the brushless DC motor’s rotation and provides a DRS function to prevent damage to the actuator in a stall condition, and to generate the position feedback signal without the need for mechanical feedback potentiometers. The actuator may be stalled anywhere in its normal rotation without the need of mechanical end switches.
The AF24-MFT S US is mounted directly to control shafts up to1.05" diameter by means of its universal clamp and anti-rotation bracket. A crankarm 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 AF24-MFT US actuator is shipped at +5° (5° from full failsafe) to provide automatic compression against damper gaskets for tight shut-off.
Product Specifications
| Power supply |
24 VAC, ± 20%, 50/60 Hz
24 VDC, ±10% |
| Power consumption |
2.5 W holding, 6 W running |
| Transformer sizing |
10 VA (Class 2 power source) |
| Electrical connection |
3 ft, 18 GA, appliance cable,
1/2” conduit connector |
| Overload protection |
electronic throughout 0 to 95°
rotation |
| Operating range Y* |
2 to 10 VDC, 4 to 20 mA (w/500Ω,
1/4 W resistor) ZG-R01 |
| Input impedance |
100kΩ
for 2 to 10 VDC (0.1 mA)
500Ω for 4 to 20 mA
1500Ω for PWM, Floating point and On-Off
control |
| Feedback output U* |
2 to 10 VDC, 0.5 mA max |
| Torque |
min 133 in-lb (15 Nm) |
| Direction of rotation* |
spring: reversible with CW/CCW
mounting; motor: reversible with built-in switch |
| Mech. angle of rotation* |
95°, adjustable 35° to 95° w/ZDB-AF2 |
| Running time motor* |
150 seconds constant |
| Running time spring |
<20 sec spring return fail safe
position |
| Angle of Rotation Adaptation* |
Off (Default) |
| Override control* |
Min. (Min Position) = 0%
- ZS (Mid. Position) = 50%
- Max. (Max. Position) = 100% |
| Position indication |
visual indicator, 0° to 95° (0° is
spring return position) |
| Auxiliary switches |
2 x SPDT 7A (2.5A) @ 250 VAC, UL
listed, one set at +5°, one adjustable 25° to 85° |
| Manual override |
3 mm hex crank (supplied) |
| Humidity |
5 to 95% RH, non-condensing |
| Ambient temperature |
-22 to +122° F (-30 to +50° C) |
| Storage temperature |
-40 to +176° F (-40 to +80° C) |
| Housing |
NEMA 2, IP54 |
| Housing material |
zinc coated metal |
| Noise level |
less than 45 dB (A) |
| Agency listings |
UL 873 listed, CE, CSA C22.2 No. 24
certified |
| Quality standard |
ISO 9001 |
| Servicing |
maintenance free |
| Weight |
6.0 lbs. (2.7 kg.) |
| * Variable when
configured with MFT options |