The NKR F1 monitors 1-phase to 3-phase mains supplies for the correct phase sequence, overvoltage and undervoltage. This means that it can also detect open circuits in the neutral conductor and the overvoltages which generally result from this, preventing damage to electrical equipment. The reaction time can be set in the range 0.1 to 5 seconds.
After a fault, the relay can return automatically to the normal operating mode or only after the fault has been acknowledged with an internal or external button.