Siemens AG 3UG4651-2AA30 Speed Monitoring Relay

Siemens 3UG4651-2AA30 is a digital speed-monitoring relay from the SIRIUS family that supervises motor speed and detects under/overspeed and standstill conditions in drive systems. It measures shaft speed from 0.1 to 2200 rpm and provides a single changeover contact with an optional fault buffer; the measuring circuit is not galvanically isolated from the control supply. The unit is powered from 24 V AC/DC (50–60 Hz) and offers adjustable ON-delay from 1 to 900 s, tripping delay from 0.1 to 99.9 s, and hysteresis from 0.1 to 99 rpm, with a spring-loaded connection system for secure wiring. Its compact DIN-rail enclosure (~86 mm x 22.5 mm x 103 mm) carries IP20 protection, suitable for panel mounting in industrial control panels.