813S MachineAlert, 3-Phase, Voltage Monitoring Relay, 440-480V AC, Self-Powered, 50 √ 400 Hz, Under & Overvoltage Protection, 2-SPDT Contact, Adjustable Time Delay, Phase – Loss/Imbalance/Reversal Protection, Programmable Latch or Inhibit at Set Level – 813S-V3-480V