Voltage monitor (50Hz supply)
The voltage monitor signals and eliminate over- and undervoltage variations (even the minor ones). The sensitivity of the voltage monitor is adjustable. The voltage monitor signals minor voltage variations. If required, the contact opens itself to safely isolate the instllation and triggers a buzzer. A timer can be set to bring back power as soon as the defect has been removed.
Here are a few causes for overvoltage surges: connection of one phase on the neutral (inversion of wires in a 3-phase connection), connection of a phase wire to the earth, neutral interruption, runaways, distance).