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 95deg of rotation and is provided
with a graduated position indicator showing 0 to 95deg. The
actuator will synchronize the 0deg 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 95deg 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 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 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 +5deg (5deg from full
fail-safe) to provide automatic compression against damper gaskets
for tight shut-off.
Additional Information
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