What are the power requirements for the airflow indicator and its control and alarm system?

• A. 115 VAC, 60 HZ, single phase
• B. 230 VAC, 50 HZ, three phase
• C. 24 VAC, single phase
• D. 12 VDC

Answer: (A)

The power supply for an airflow indicator with its control and alarm is typically the standard line power used in North American facilities. Using 115 VAC at 60 Hz in a single-phase configuration provides sufficient current to drive the indicator, any control electronics, and audible/visual alarms, while staying compatible with common building wiring and safety interlocks. This setup avoids the need for additional transformers or special power systems and offers reliable operation for safety-critical signaling.

Choices based on European or low-voltage control standards—such as 230 VAC at 50 Hz three-phase, or low voltages like 24 VAC or 12 VDC—are not the norm for this type of safety signaling in many US-based environments, where line-powered indicators and alarms are preferred for robustness and simplicity.