Allen-Bradley 813S-V0B Line Voltage Monitor Relay

Allen-Bradley 813S-V0B Line Voltage Monitor Relay is a solid‑state voltage supervision device in Rockwell Automation’s 813S family, engineered to monitor 480 VAC three‑phase power and deliver a precise, fast control signal to motor starters and protective circuits when voltages stray outside tolerance. The V0B variant denotes the 480 V, three‑phase model in Series B, with a monitored circuit current rating of 8–10 A, enabling a reliable interlock or signal path to downstream contactors without overloading the monitored line. Built‑in LED indicators provide immediate fault feedback, including phase loss or incorrect phase sequence, helping technicians diagnose loss of voltage conditions or wiring faults that could otherwise cause unwanted starts or equipment damage. This voltage‑monitor relay is commonly deployed in panel assemblies powering conveyors, pumps, and other industrial loads from 480 VAC networks, where supervision of supply quality is essential to prevent nuisance starts and protect motor life; its solid‑state output supports clean digital signaling to control circuitry while maintaining robust protection against transient disturbances on the incoming supply.