Belimo NRF24A-SZ - rotary actuator with spring return for ball valves

Belimo NRF24A-SZ rotary actuator

NRF24A-SZ is a modulating rotary actuator with a safety function for ball valves. Signal Y controls movement to the operating position while simultaneously tensioning the return spring. When the power supply is interrupted, the spring moves the valve to the safety position: closed (NC, A – AB = 0%). For valves with an L-port, the data sheet specifies the safety-function direction as A – AB = 100%.

Key features and specifications

• Motor torque: 10 Nm; safety-function torque: 10 Nm.
• Nominal voltage: AC/DC 24 V; AC voltage frequency: 50/60 Hz.
• Control signal Y range: 0.5...10 V; position feedback signal U: 0.5...10 V.
• Motor running time: 90 s / 90°; safety-function running time: <20 s @ -20...50°C, <60 s @ -30°C.
• Power consumption during operation: 3.5 W; in the rest position: 2.5 W; sizing power: 6 VA.
• Power and control connection: 1 m cable, 4x 0.75 mm².
• Manual operation using a crank and locking switch; adjustable rotation angle with mechanical end stops.
• Mechanical position indicator; degree of protection IP54.
• Ambient temperature: -30...50°C.

The actuator is intended for stationary heating, ventilation and air conditioning installations. It is mounted directly on the ball valve using one screw; its orientation relative to the valve can be selected in 90° increments.