The Siemens 3RP1540-1AJ31 is a SIRIUS time relay with a single changeover relay output, adjustable from 0.05 to 600 seconds. Control supply is 100-127 V AC/DC, and the thermal current rating is 5 A. It mounts on a 35 mm DIN rail via screw and snap-on fastening, fitting a standard 22.5 mm wide slot in the panel.
What the ratings mean for fit
The 0.05-600 s adjustable time range covers short pulse delays up to ten-minute intervals, so it handles most conveyor interlock, pump sequencing, and star-delta transition timers without needing a separate module. The 5 A thermal current (Ith) is the continuous carry rating through the contacts — adequate for pilot-duty loads like contactor coils and indicator lamps, but not for direct motor switching. The 100-127 V AC/DC control supply matches standard North American control voltages; at 50/60 Hz the pickup threshold is 85% of rated voltage, so it pulls in reliably even on a sagging 120 V line.
Mounting and wiring
Screw and snap-on mounting onto 35 mm DIN rail, any position. The 22.5 mm width means it takes one standard module slot — no crowding in a dense panel. Terminals accept 20-14 AWG stranded wire; tighten to 0.8-1.2 N·m. Basic insulation per the type, so keep it behind a panel door or in an enclosure.