The RM22UA3 1-phase voltage control relays monitor the overvoltage or undervoltage events with or without memory and overvoltage and undervoltage events in window mode. They feature a sealable cover to help protect the settings, a dial pointer LED indicator for relay power ON status, a relay output status LED and a control status indicator LED. The RM22UA3 most common applications are protection of electronic or electromechanical devices against overvoltage and undervoltage; emergency power supply switching in abnormal conditions; DC motor overspeed control; monitoring of AC or DC supplies; battery and speed monitoring (with tacho-generator).