The Siemens 3UG4816-1AA40 is a SIRIUS network monitoring relay with digital setting, designed to monitor phase sequence, phase failure, asymmetry, and undervoltage/overvoltage on three-phase AC systems. It packs five monitoring functions into a single 22.5 mm-wide housing that snaps onto a DIN rail — no drilling, no extra panel space. The LCD display shows the measured values and fault codes directly, so a commissioning engineer can read the line condition without a handheld meter. Rated for 3 A at both 250 V and 400 V at 50/60 Hz, the output relay switches control signals to a PLC input or contactor coil. The adjustable start-up delay (0 to 999.9 s) lets you stagger motor starts after a power restoration, avoiding a simultaneous inrush that could trip an upstream breaker. Asymmetry detection is built in, so the relay catches a phase imbalance before it cooks a motor winding.
Integration Notes
Snap-on mounting to a 35 mm DIN rail per EN 60715. The 22.5 mm width means it occupies one standard module position — useful when filling a crowded panel. Operating temperature range is -25 to +60 °C; storage range -40 to +85 °C. Pollution degree 2 (non-conductive pollution only). IP20 finger-safe terminals accept 2 x (20–14 AWG) solid or stranded wire. Any mounting position is allowed, so it fits vertical or horizontal rail runs. The relay supports both auto-reset and external reset, configurable via the front-panel menu. IO-Link communication at COM2 (38.4 kBaud) is available for parameter readback and remote monitoring — useful if the panel is connected to a higher-level asset management system.