Siemens 3RT1015-1KB42-ZX95 — SIRIUS Size S00 Power Contactor, 24 V DC Coil
The Siemens 3RT1015-1KB42-ZX95 is a SIRIUS power contactor in the compact Size S00 frame, with a 24 V DC magnet coil. It's built for switching motor loads in control panels and snaps onto a 35 mm DIN rail per EN 50022. The varistor built into the coil circuit handles surge suppression — no separate suppressor module needed. At 400 V AC-3 duty it's rated for 3 kW motor switching, and the mechanical life of 30 million operations tells you the armature and spring set are good for a long production run before the contacts wear.
What the Ratings Mean for Fit
The 24 V DC coil draws 2.3 W both on pickup and hold — that's a sealed power draw, not a spike. If you're feeding it from a 24 VDC power supply, budget that 2.3 W per contactor continuously. The AC-3 motor rating at 400 V is 3 kW, which matches a standard 4-pole induction motor of that size. At 690 V the same contactor handles 4 kW, so the voltage bump gives you headroom on the same frame. The AC-4 rating of 6.5 A at 400 V covers reversing or plugging duty where the contacts break full-load current — that's a tougher thermal cycle than AC-3, and the S00 frame handles it without upsizing. The screw-type terminals on the main circuit accept 2x (0.5...1.5 mm²) solid or 2x (0.75...2.5 mm²) stranded, with a max of 2x (0.75...4 mm²). For AWG, that's 2x (20...16) solid or 2x (18...14) stranded. The 6 mm side clearance to adjacent devices is the minimum for heat dissipation — stack them tighter and you'll need to derate the continuous current. Pollution degree 3 means it's rated for industrial environments with conductive dust or condensation, so no conformal coating needed in most panel builds.
Panel Integration
The S00 frame measures 45 mm wide, 57.5 mm high, and 72 mm deep. It mounts via screw or snap-on onto 35 mm DIN rail. Side-by-side mounting is permitted — the 6 mm gap is the minimum, and with that spacing you can line up several contactors on the same rail without extra brackets. The IP20 rating on the front and terminals means it's protected against finger contact but not water ingress; keep it inside a sealed enclosure if washdown is nearby.