The Siemens SIRIUS 3UG3511-1BQ50 is a 22.5 mm monitoring relay that checks phase sequence and phase failure on three-phase supplies from 3x 200 V to 3x 460 V AC at 50/60 Hz. Its two changeover contacts (2 CO) give you a separate signal path for each fault condition, so a PLC or annunciator can distinguish a lost phase from a reversed rotation without extra logic. Rated for the full line-to-line range in one unit — 200 V through 460 V — which covers most 230/400 V and 277/480 V industrial panels without needing a voltage-range variant. The relay self-powers from the monitored lines; no separate control supply is required.
IP20 finger-safe terminals are screw-type, sized for the control-circuit wiring typical in motor control centers. No derating needed for the common panel ambient.