The Siemens 3RT1025-1AL20-ZW97 is a SIRIUS power contactor in Size S0, designed for switching motor loads up to 11 kW at 690 V AC-3 (50/60 Hz).
The AC-3 rating of 11 kW at 690 V tells you this contactor handles standard squirrel-cage motor switching at that voltage. For resistive or lightly inductive loads (AC-1), the contactor is rated 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V. The auxiliary contact ratings cover 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, and 0.3 A at 220 V — useful for control circuit integration. The 91 mm depth, 45 mm width, and 85 mm height place it in the standard S0 footprint. The IP20 front and IP00 terminals mean the enclosure provides finger-safe protection on the front face, but the terminals require a separate touch-safe cover or enclosure.
Main circuit terminals accept screw-type connections: solid 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²), max 2x (0.75 to 4 mm²). Stranded conductors: 2x (1 to 2.5 mm²) or 2x (2.5 to 6 mm²), max 2x 10 mm². AWG equivalents: 2x (16 to 12), 2x (14 to 10), or 1x 8. Strip length and torque spec follow standard Siemens practice for the S0 frame. For type 2 coordination (no-weld protection), the required upstream fuse is 25 A gL/gG. For type 1 coordination (limited damage allowed), the fuse can be 63 A gL/gG. This is the spec to hand to the panel builder when sizing branch protection.