Belimo BFN24 - spring-return actuator for fire and smoke dampers

Belimo BFN24 – actuator for fire and smoke dampers

BFN24 is a spring-return actuator for 90° fire and smoke dampers in ventilation and air-conditioning systems. While the motor is running, the spring is tensioned; if the power supply is interrupted, its stored energy moves the damper to the safety position.

Key technical data

• Supply: AC/DC 24 V; rated voltage frequency: 50/60 Hz.
• Control: Close/Open.
• Motor torque: 9 Nm; safety function torque: 7 Nm.
• Motor running time: <60 s / 90°; safety function running time: 20 s @ -10...55°C, <60 s @ -30...-10°C.
• Rotation angle: max. 95°; motor direction of movement selected by L/R mounting.
• Auxiliary switches: 2x SPDT, switching points 5° / 80°.
• Mechanical connection: 12x12 mm form-fit connection, through hollow shaft.
• Power consumption during operation: 3.2 W; in rest position: 1.2 W; power for cable sizing: 4.3 VA.
• Power and control connection: 1 m cable, 2x 0.75 mm², FRNC (halogen-free); auxiliary switch connection: 1 m cable, 6x 0.75 mm², FRNC (halogen-free).
• IEC/EN protection rating: IP54; IEC/EN protection class: III, Safety Extra-Low Voltage (SELV).

Manual operation with a limit stop is possible when the power is switched off. The position is indicated by a mechanical indicator. A hand crank, indicator and protective bag are included.

The actuator is adapted and installed on the damper by the damper manufacturer. Auxiliary switches must not be used simultaneously in mains-voltage and safety extra-low-voltage circuits.