What this contactor is and what it does
The Siemens SIRIUS 3RT1015-2KB42-ZW98 is a size S00 power contactor with a 24 V DC coil, designed for switching motor loads in control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, and its spring-loaded terminals on the main current circuit accept solid or stranded conductors up to 2x 2.5 mm² (or 2x 24-14 AWG). The integrated varistor surge suppressor handles coil suppression internally — no external diode needed, which saves a wiring step and avoids polarity mistakes at 2am. The AC-3 motor switching rating is 3.5 kW at 400 V and 4 kW at 690 V, meaning it handles standard three-phase induction motors up to those power levels in normal starting duty. For AC-4 (reversing or inching) the rating drops to 6.5 A at 400 V — the buyer should size for the actual duty cycle, not just the motor nameplate. The mechanical life is rated at 30 million operations, so this is a long-run part for high-cycle applications like conveyors or packaging lines.
Mounting and integration into a panel
The S00 frame is compact at 45 mm wide, 60 mm high, and 73 mm deep — it fits tightly on a DIN rail without crowding adjacent devices. Side-by-side mounting is allowed, and the required side clearance is only 6 mm, so you can pack multiple contactors in a row. The IP20 rating on the front and terminals means it's protected against finger contact but not washdown; keep it inside a closed panel. Pollution degree 3 rating suits industrial environments with conductive dust or humidity. For type 2 coordination (no damage to the contactor under short circuit), the required upstream fuse is gL/gG 20 A. For type 1 coordination (contactor may need replacement after fault), use a gL/gG 35 A fuse. This matters when the panel design specifies selectivity with downstream motor protection.
Coil and auxiliary contact details
The DC coil draws 2.3 W both on closing and holding — no power drop after pick-up, so the control transformer must supply continuous 2.3 W per contactor. The auxiliary contact block (integrated in this variant) is rated for 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V, covering typical PLC-level signals and small relay loads. The operating temperature range is -25 to +60 °C, with a maximum altitude of 2 000 m before derating.