The 3RT1526-1AK60: The 25 A per-pole rating (both NO and NC) is the continuous thermal current — it carries motor or resistive loads up to that level, but the real switching duty depends on the load type. For motor starting (AC-3), you derate; the fuse protection spec of 35 A gL/gG (type 2 coordination) tells you the upstream short-circuit protection limit for a coordinated starter. The 6 kV rated impulse withstand means the contactor handles transient overvoltages typical in 400 V industrial panels without flashover — important for reliability on dirty mains. The S0 frame size is the physical footprint: 85 mm high, 61 mm wide, 91 mm deep.
Both main and auxiliary/control circuits use screw-type terminals. The main circuit accepts solid or stranded copper: 2x (0.5…1.5 mm²), 2x (0.75…2.5 mm²), or max 2x (0.75…4 mm²); AWG equivalents are 2x (20…16), 2x (18…14), and 1x 12. This covers typical panel wire sizes for 25 A circuits — no need for pin terminals or ferrules if using stranded, though ferrules are recommended for repeated re-termination.
The coil draws 7.5 VA at 50 Hz; at 60 Hz the power factor is 0.28. The rated control supply voltage at 50 Hz is 110 V, at 60 Hz is 120 V. Switching times: AC pickup 13…25 ms, arcing time 10…15 ms. The auxiliary contacts are rated for switching at various DC voltages: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, 3 A at 400 V, 1 A at 440 V — these are the DC-13 breaking capacities for the control circuit, not the main load.
This is an active, current-production part. No last-time-buy window, no successor part number to track. For a critical spare or a BOM line, you can specify it with confidence that the supply channel is standard.