NFB24-MFT Belimo Actuator


Motor ,Actuator, Spring Return, 90 in-lb, 500 Ohm for 4-20mA, 1500 Ohm for PWM, floating point and On/Off, 24Vac, 24Vdc (NFX24-MFT)

10 in stock


Spring, 90in-lb, MFT, 24V (NFX24-MFT)


Installation Guide


For fail-safe, modulating control of dampers in HVAC systems. Actuator sizing should be done in accordance with the damper manufacturer’s specifications. A feedback signal is provided for position indication.


Default parameters for 2 to 10 VDC applications of the NF..-MFT actuator are assigned during manufacturing. If required, custom versions of the actuator can be ordered. The parameters are variable and can be changed by three means: Factory pre-set or custom configuration, set by the customer using PC-Tool software or the handheld ZTH US.


The NF..24-MFT actuator provides 95° of rotation and is provided 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 override 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 microprocessor. The microprocessor provides the intelligence to the ASIC to provide a constant rotation rate and to know the actuators’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 NF..24- MFT is mounted directly to control shafts up to 1.05” diameter by means of its universal clamp and anti-rotation bracket. A crank arm 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 NF..24- MFT actuator is shipped at 5° (5° from full fail-safe) to provide automatic compression against damper gaskets for tight shut-off.




Angle of Rotation

  • 95°

Direction of Rotation (Fail-Safe)

  • Reversible with cw/ccw mounting

Power Consumption (Holding)

  • 3 W

Safety Function

  • YES

Shaft Diameter

  • 1/2…1.05″ round
  • centers on 1/2″ and 3/4″ with insert
  • 1.05″ without insert

Actuator Type

  • Spring return


  • Air

Control Type

  • MFT/Programmable

Degree of Protection

  • IP54
  • NEMA 2
  • UL Enclosure Type 2

Electrical Connection

  • Cable

Manual Override

  • 5 mm hex crank (3/16″ Allen)
  • supplied

Power Consumption (Running)

  • 5 W

Product Type

  • Actuator

Protection category

  • IP54

Running Time (Fail-safe)

  • <20 s

Running Time (Motor)

  • Default 150 s
  • variable 40…150 s


  • 90 in-lb [10 Nm]

Voltage AC/DC

  • AC/DC 24 V

Additional Information

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Additional information

Weight 8 lbs
Dimensions 2 × 2 × 2 in