SIRIUS S0 power contactor — 3RT1025-1AK60-ZW96
The Siemens 3RT1025-1AK60-ZW96 is a SIRIUS S0-frame power contactor rated for motor switching at 7.5 kW in AC-2 duty at 400 V and 15.5 A in AC-4 duty at 400 V. The S0 frame measures 45 mm wide by 85 mm high by 91 mm deep — a standard footprint that fits alongside other SIRIUS components in a control panel.
Motor duty ratings and coordination
The AC-4 rating at 15.5 A / 400 V covers plugging and inching duty — the contactor handles the full locked-rotor current during reversing or jogging cycles. For short-circuit protection, Type 1 coordination requires a 63 A gL/gG fuse; Type 2 coordination requires a 25 A gL/gG fuse. These fuse values define the maximum let-through energy the contactor can withstand without damage to downstream components.
Termination and environmental limits
Main circuit screw terminals accept solid or stranded conductors: 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), or max. 2x (0.75–4 mm²). AWG equivalents are 2x (16–12), 2x (14–10), or 1x 8. The auxiliary contact block terminals accept 2x (1–2.5 mm²) or 2x (2.5–6 mm²), max. 2x 10 mm². Pollution degree 3 (conductive pollution) applies, so the contactor is suited for industrial environments where occasional condensation or light contamination occurs. Front protection is IP20; the terminals themselves are IP00.