Select another country or region to see the content that is available for your location


How does the power fault alarm relay operate?


Following are the two circuit diagrams that explain the relay operation. The first diagram demonstrates the red contact is normally open under a normal operating condition, meaning that the 12-48VDC Power Supply constantly delivers power to the switch without any power failure. "Normally" refers to a de-energized condition of the red contact as there is no magnetic force around the copper coil.

The second diagram demonstrates that the 12-48VDC Power Supply has somehow malfunctioned, resulting in a power cut. Therefore, a current flows through circuit (A) and the copper coil generates a magnetic force that attracts the red contact and forms a closed circuit (B). The buzzer starts to make a loud sound due to the power failure event.