BELIMO AF24-SR SPRING RETURN ACTUATOR

Description

BELIMO AF24-SR SPRING RETURN ACTUATOR 24V.
AF24-SR US, AFR24-SR US
Proportional damper actuator, spring return safety, 24 V for 2 to 10 VDC, 0 to 20 V phasecut
and 4 to 20 mA control signal. Output signal of 2 to 10 VDC for position indication
Application
For proportional modulation of dampers in HVAC systems.
Actuator sizing should be done in accordance with the damper
manufacturer’s specifications.
The actuator is mounted directly to a damper shaft up to 1.05”
in diameter by means of its universal clamp. A crankarm and
several mounting brackets are available for applications where
the actuator cannot be direct coupled to the damper shaft.
The actuator operates in response to a 2 to 10 VDC, with the
addition of a 500Ω resistor, a 4 to 20 mA control input from an
electronic controller or positioner. A 2 to 10 VDC feedback
signal is provided for position indication or master-slave applications.
Operation
The AF series actuators provide true spring return operation for
reliable fail-safe application and positive close-off on air tight
dampers. The spring return system provides constant torque to
the damper with, and without, power applied to the actuator.
The AF series provides 95° of rotation and is provided with a
graduated position indicator showing -5 to 90°. The AF has a
unique manual positioning mechanism which allows the setting
of any damper position within its 95° of rotation. When
power is applied to the AFR series its “one time use” mechanism
is released. The actuator is shipped in the zero position
(5° from full fail-safe) to provide automatic compression
against damper gaskets for tight shut-off. When power is
applied, the manual mechanism is released and the actuator
drives toward the full fail-safe position. The actuator will
memorize the angle where it stops rotating and use this point
for its zero position for its normal control operations. The
manual override can also be released physically by the use of
a crank supplied with the actuator.
The AF 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 zero position. The ASIC monitors and controls
the brushless DC motor’s rotation and provides a digital rotation
sensing function to prevent damage to the actuator in a
stall condition. The actuator may be stalled anywhere in its
normal rotation without the need of mechanical end switches.