Accusense 305-BB1-N-B3 Airflow Switch

accusense 305-BB1-N-B3 Airflow Switch (Cambridge AccuSense 305-BB1-N-B3) is a bi-directional, base-mount sensor in the AccuSense Series 300/305 that continuously monitors airflow to detect directional losses or reversals and to trigger a fault signal when airflow becomes insufficient. The switch uses solid-state electronics with an open-collector NPN output that sinks current to the return VDC and requires a pull-up; it operates on a 5 V supply (305-series) and draws about 100–140 mA with a total power dissipation around 0.2–0.8 W. Environmental specs include an operating temperature range of 5–60 °C, non-condensing humidity from 10–95% RH, and a storage range of -10 to 80 °C; startup and fault-response characteristics are 3 seconds (above 15 °C) / 30 seconds (below 15 °C) for startup and 3 seconds / 30 seconds for fault signaling. Typical applications cover cleanrooms, semiconductor fabrication facilities, electronics enclosures, and HVAC ducts where reliable detection of airflow direction or loss is critical.