The 3UG4616-1BR28-0AA1: The 160-690 V AC range covers standard low-voltage networks (400/480 V) plus 690 V industrial systems — no external PT needed for most panels. The hysteresis (1-20 V) sets the reset band after a voltage event; a tight 1 V hysteresis catches nuisance trips on a stable line, while 20 V prevents chatter on a weak supply. Off delay (0-20 s) lets you ride through momentary sags without tripping — set it to 2-5 s for motor starting dips. Two CO (changeover) contacts give one normally-open and one normally-closed set per fault output. That is enough to drive a PLC input and a local alarm lamp simultaneously. The screw terminals accept standard control wiring — no special tooling needed. The reference code according to IEC 81346-2 is K, which designates a relay or contactor function in the panel schematic. This helps with documentation and BOM alignment for IEC-based projects.
This relay is built for panel-level voltage monitoring in motor control centers, distribution boards, and machine supply circuits. It protects downstream equipment from phase loss, phase reversal, and sustained over/undervoltage — common causes of motor winding failure and drive input damage.