The Siemens 3UG3051-1AC40 is a SIRIUS monitoring relay for underspeed detection, covering 0.1 to 600 1/min across four selectable ranges. The 45 mm wide housing mounts via screw or snap-on to DIN rail.
The 1 % relative repeat accuracy means the trip point stays tight cycle to cycle — useful for consistent underspeed detection on conveyors or fans. The 10 % relative metering precision is the measurement tolerance, not the repeatability; the relay's detection is coarser than its switching consistency. Delayed switching is built in, so you can set a time delay to avoid nuisance trips on transient slowdowns.
Screw-type terminals for the control and output circuits. The 100 mm depth and 100 mm height fit standard 45 mm wide DIN-rail enclosures. No removable terminal for auxiliary/control circuit — wiring stays fixed to the relay body.