If the measured voltage of all phases exceeds the switching threshold Us including hysteresis , the time delay (t) starts and the green LED U/t flashes. After the delay time (t) has elapsed, the output relay R is energized (yellow LED lights up, green LED U/t flashes). If the measured voltage of one of the connected phases falls below the switching threshold Us, the output relay is no longer energized (yellow LED goes out, green LED U/t goes out).
