TEMP. IND &
REG. EQUIP.
AF24-MFT (-S) US
Proportional damper actuator, Spring Return Fail-Safe, Multi-Function Technology®
Technical Data AF24-MFT (-S) US
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 3 ft, 18 GA, appliance cable,
connection 1/2”conduit connector
Overload protection electronic throughout 0 to 95°rotation
Operating range Y* 2 to 10 VDC
4 to 20 mA (w/500 Ω, 1/4 W resistor) ZG-R01
Input impedance 100kΩfor 2 to 10 VDC (0.1 mA)
500Ωfor 4 to 20 mA
1500Ωfor 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 Off (Default)
Adaptation*
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
(AF24-MFT-S US) 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 UL873listed, CE,CSA C22.2 No. 24certified
Quality standard ISO 9001
Servicing maintenance free
Weight 6.0 lbs. (2.7 kg.)
*Variable when configured with MFT options
Dimensions [All numbers in brackets are in millimeters.]
•Torque min. 133 in-lb
•Control 2 to 10 VDC (DEFAULT)
•Feedback 2 to 10 VDC (DEFAULT)
Application
For proportional modulation of dampers and control valves in
HVAC systems. The AF24-MFT US provides mechanical spring
return operation for reliable fail-safe application.
Default/Configuration
Default parameters for 2 to 10 VDC applications of the
AF24-MFT US actuator are assigned during manufacturing.
If required, custom versions of the actuator can be ordered.
The parameters noted in the Technical Data table are variable.
These parameters can be changed by three means:
•Pre-set configurations from Belimo
•Custom configurations from Belimo
•Configurations set by the customer using the MFT-Handy®
or the MFT-Actuate™PC software application.
Operation
The AF24-MFT US actuator provides 95°of rotation and is provid-
ed with a 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 over-
ride 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 microproces-
sor. 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 AF24-MFT US is mounted directly to control shafts up to
1.05" 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 cou-
pled to the damper shaft. The spring return system provides mini-
mum specified torque to the application during a power interrup-
tion. The AF24-MFT US actuator is shipped at +5°(5°from full
fail-safe) to provide automatic compression against damper gas-
kets for tight shut-off.
Note: Please See Documentation on
Multi-Function Technology (pg 255)
