The sollatek svs monitors power the mains voltage continously, if the voltage rises or drops, the svs will stabilize the output to ensure the voltage reaching your equipment remains constant at 230v(+/-6%) within the operating range of the unit. if the input voltage falls below 142v or rises above 295v, the svs will disconnect the output, thereby protecting the load, once the mains voltage returns again within acceptable limits, the svs will reconnect the output following a start up delay.