Belimo NFB Series Mounting Installation Instructions

Mounting Installation Instructions
NFB, NFX Series
Features
• On/Off, 2-10 VDC, Variable MFT, Spring Return, 24 VAC
or 24 VDC, 120 VAC-240 VAC
• 90 in-lb min. torque, for control of air dampers
Dimensions (Inches [mm])
K7-2 (supplied)
1/2" Centered 3/4" Centered
(Default) (Field Selectable)
1.05" Centered
(Field Selectable)
General Information
Application
For On/Off, VDC, programmable MFT, fail-safe control of
dampers in HVAC systems. Actuator sizing should be
done in accordance with the damper manufacturer's
specifications. Control can be on/off, 2-10 VDC or
programmable MFT.
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.
Operation
The NFB, NFX 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 consistent torque to the damper with, and
without, power applied to the actuator.
The NFB, NFX series provides 95° of rotation and is
provided with a graduated position indicator showing
-0° to 95°. The NFB, NFX series has a unique manual
positioning mechanism which allows the setting of any
damper position within its 95° of rotation. The actuator
is shipped in the zero position (5° from full fail-safe) to
provide automatic compression against damper gaskets
for tight shutoff. When power is applied, the manual
mechanism is released. The actuator will now try to
close against the -5° position during its normal control
operations. The manual override can also be released
physically by the use of a crank supplied with the
actuator.
The NFB, NFX series use a brushless DC motor which is
controlled by an Application Specific Integrated Circuit
(ASIC). The ASIC monitors and controls the actuator'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.
The NFB...-S, NFX...-S versions are provided with two
built in auxiliary switches. These SPDT switches are
provided for safety interfacing or signaling, for example,
for fan start-up. The switching function at the fail-safe
postion is fixed at 10°, the other switch function is
adjustable between 10° to 90°.
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