DGK-04F Digital Adjustable Three-Phase Over and Under Voltage Control Relay Voltage control relays are designed to protect devices with sensitive operating voltage from damage caused by mains voltage. Over Voltage : 400V - 460V AC (Adjustable) Under Voltage: 230V - 360V AC (Adjustable) Error Waiting Time : 0,1sec. - 10sec. (Adjustable) Phase Sequence Control Non-Neutral