The 3RT2025-2AL24-3MA0: Rated for 3 hp at 230 V, this contactor handles a typical small motor — pump, fan, conveyor — on a 230 V single-phase or three-phase line. The AC-3 switching frequency is 1 000 operations per hour, which is standard for general motor starting; AC-4 (inching/plugging) drops to 300/h, so don't spec it for frequent reversing duty without checking the thermal curve. The auxiliary contact block is rated for 6 A at 24 V DC, 2 A at 48 V, and derates from there — 1 A at 110 V, 0.3 A at 220 V. That's the contact rating for the control circuit, not the main power path. If you need more than one auxiliary pole, this unit ships without an auxiliary switch block, so you'll add one externally. The spring terminals on the coil side accept 2x (0.5 to 2.5 mm²), which is plenty for a 24 V DC control signal.
Size S0 means 45 mm wide, 102 mm tall, 144 mm deep — fits a standard 45 mm slot on a DIN rail. That's handy when you're shoehorning it into a tight enclosure or a swing frame. Clearances: 10 mm above and below, 10 mm forward, 6 mm to the side. That's the minimum air gap to adjacent metalwork or another device. Panel builders, leave those gaps or you'll cook the coil in a crowded row. Fine for most indoor industrial environments; if it's sitting in a hot Texas panel next to a VFD, keep the ambient under 60 °C.