The Siemens 3RT1025-1KE43 is a SIRIUS power contactor in the compact S0 frame, 45 mm wide, designed for screw and snap-on mounting onto a 35 mm DIN rail per EN 50022. It switches motor loads up to 10 kW at 500 V and 11 kW at 690 V, with an AC-4 rating of 15.5 A at 400 V for reversing or inching duty. The built-in varistor surge suppressor handles coil suppression without an external module.
Key ratings and what they mean for fit
The AC-3 motor switching rating is the one that governs most conveyor and pump loads: 10 kW at 500 V and 11 kW at 690 V. For applications that require frequent reversing or plugging (AC-4 duty), the contactor is rated 15.5 A at 400 V — that's the current it can interrupt under high electrical wear. The DC switching capability at 24 V is 10 A, useful for resistive loads like solenoids or brake coils in a shuttle aisle. The mechanical life is 10,000,000 operations, which means it outlasts most electromechanical cycles in a warehouse shuttle or crane panel without contact block replacement. The operating temperature range of -25 to +60 °C covers unheated warehouse environments, and pollution degree 3 confirms it's rated for industrial atmospheres with conductive dust.
Mounting and integration
The contactor snaps onto a 35 mm DIN rail and occupies 45 mm of panel width. Side-by-side mounting is allowed with zero gap, so you can pack multiple units on the same rail without derating for heat buildup — useful when retrofitting into an existing panel with limited space. The depth of 150 mm includes the overhang for screw terminals and the built-in varistor; verify clearance to the gland plate or door. Main circuit terminals are screw-type, accepting solid wires from 0.5 to 4 mm² (2x conductors) and stranded up to 10 mm². For Type 2 coordination (no damage to the contactor on fault), use a 25 A gL/gG fuse upstream; for Type 1 (contactor may need replacement), a 63 A fuse is allowed. The front face is IP20 finger-safe; the terminal area is IP00, so the panel must provide the enclosure protection.