What it is and where it fits
The Siemens 3RT1015-1JB41-ZX95 is a SIRIUS power contactor in frame size S00, rated for 24 VDC coil operation with a diode surge suppressor built in. It switches 10 A at 24 V (AC-12) and carries motor ratings of 3.5 kW at 500 V and 4 kW at 690 V. The contactor mounts via screw or snap-on onto 35 mm DIN rail per EN 50022, making it a direct fit into standard control panels.
Key ratings and what they mean for your panel
The 24 VDC coil draws 2.3 W both on closing and holding — no power penalty for keeping it engaged. The integrated diode suppresses the inductive kickback from the coil, which matters when the contactor shares a DC supply with sensitive electronics like a PLC output card. Without that diode, the flyback voltage can couple noise into the 24 V bus. For motor switching in AC-3 duty at 400 V, the contactor is rated for 3 kW. In AC-4 (reversing or plugging) at 400 V, it handles 6.5 A. The AC-1 resistive rating reaches 20 A at 400 V. These numbers define the real load envelope — the AC-3 figure governs most conveyor and pump starts. Short-circuit coordination is specified: type 2 coordination requires a 20 A gL/gG fuse; type 1 allows up to 35 A gL/gG. If the panel design calls for type 2 to minimize downtime after a fault, the 20 A fuse limit is the binding constraint on upstream protection.
Mounting and wiring constraints
The contactor occupies a 45 mm wide footprint on the DIN rail, with a depth of 72 mm and height of 57.5 mm. Side-by-side mounting is permitted with a 6 mm gap to adjacent devices for heat dissipation. Screw terminals accept solid conductors from 0.5 mm² up to 4 mm² (max 2x 4 mm² per clamp). The IP20 rating on the front and terminals means it's protected against finger contact but not washdown — standard for enclosed panel installation.