Belimo BFN24-SR-T - spring-return actuator for fire dampers

Belimo BFN24-SR-T actuator

Spring-return actuator with a BAT thermal release (72°C) for 90° fire and smoke dampers in ventilation and air-conditioning systems. The analogue control signal Y sets the damper to the operating position and simultaneously tensions the return spring. An interruption to the power supply returns the damper to the safety position.

Key features and specifications

• Nominal supply: AC/DC 24 V; frequency 50/60 Hz.
• Modulating control: operating range Y 2...10 V; position feedback signal U 2...10 V.
• 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.
• BAT release with thermal fuses responding at 72°C to the temperature inside and outside the duct.
• Two auxiliary switches 2x SPDT with switching points at 5° / 80°.
• 12x12 mm form-fit connection, through hollow shaft; max. rotation angle 95°.
• Motor direction selected by L/R mounting; manual adjustment with stop and mechanical position indicator.
• Power consumption during operation: 3.7 W; in standby: 1.2 W; for cable sizing: 6.5 VA.
• Power and control connection: 1 m cable, 4x 0.75 mm², halogen-free; auxiliary switch connection: 1 m cable, 6x 0.75 mm², halogen-free.
• IEC/EN protection rating: IP54; IEC/EN protection class: III, Safety Extra-Low Voltage (SELV).

The set includes a manual crank, indicator and protective bag. According to the documentation, the actuator is adapted and mounted on the damper by the damper manufacturer and supplied directly to manufacturers of safety dampers.