Motor switching ratings that decide the fit
The 3RT1025-1AP08-0QA2: The AC-2 rating at 400 V is 7.5 kW — that's the duty for slip-ring motors or moderate loads. The AC-4 rating at 400 V is 15.5 A, which covers reversing or inching applications where the contactor breaks full motor current. For direct-on-line starting, the AC-3 capability shows through the 500 V / 10 kW and 690 V / 11 kW ratings. The 690 V figure is worth noting: it means this S0 frame handles 690 V line supplies common in European industrial networks without stepping up to a larger frame.
Coordination and protection
Type 1 coordination (no damage to the contactor, but may need replacement after a fault) calls for a 63 A gL/gG fuse. Type 2 coordination (contactor remains operational after a fault) requires a 25 A gL/gG fuse. If you're designing to IEC 60947-4-1, the 25 A fuse is the one that keeps the contactor in service after a short circuit.
Environmental and mounting constraints
Operating temperature range is -25 to +60 °C during operation, with pollution degree 3 (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation). The IP20 front protection means it's safe for finger contact inside a panel; the IP00 terminal area requires the installer to ensure no accidental contact. Side-by-side mounting is permitted with 6 mm spacing at the side — no derating needed for adjacent units if that gap is maintained.