What this part is and what it does
The Siemens 3RT1015-2GG28-0NA4 is a SIRIUS power contactor in the compact S00 frame size, designed for switching motor loads in control panels and industrial machinery. It mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022, and uses spring-loaded terminals for the main current circuit — no screwdriver needed for the power wiring, which speeds up panel assembly and reduces the risk of loose connections under vibration. Rated for AC-3 duty at 4 kW on 690 V and 3.5 kW on 500 V, it handles the most common three-phase motor starting loads in this frame class. The AC-4 rating of 6.5 A at 400 V covers reversing or inching applications where the contactor makes and breaks stalled-rotor current. For resistive loads (AC-1), the operating current maxes at 10 A. The coil includes a full-wave rectified surge suppressor built in — no external snubber needed on the coil circuit.
Key ratings and what they mean for fit
The 4 kW at 690 V AC-3 rating is the headline number for motor switching — it tells you this contactor can start and stop a 4 kW induction motor on a 690 V line. But the real-world selection parameter is often the AC-3 current at the system voltage you actually run. At 400 V, the AC-3 rating is 3 kW, which corresponds to roughly a 7 A motor full-load current — a common size for small pumps, fans, and conveyors. The AC-4 rating of 6.5 A at 400 V is the one to check if the contactor sees frequent plugging or jogging duty; that current is lower than the AC-3 value because the contacts have to break locked-rotor current. The auxiliary contact block is a single instantaneous contact (1 NO or 1 NC depending on wiring). If your circuit needs more auxiliary contacts for status feedback or interlocking, you'll need to add a side-mount auxiliary contact block — the S00 frame accepts the standard Siemens auxiliary blocks. The IP20 protection on the front and terminals means it's safe for finger contact in a closed panel, but not for washdown environments.
Integration and mounting
Mounts on 35 mm DIN rail per DIN EN 50022 — screw or snap-on. The S00 frame is 45 mm wide, 60 mm tall, and 114 mm deep, so it fits in a standard 45 mm slot on a DIN rail. Side-by-side mounting is allowed with 6 mm clearance to adjacent devices, which keeps the panel density high. The operating temperature range of -25 to +60 °C covers most indoor panel environments, and the pollution degree 3 rating means it's suitable for industrial atmospheres with conductive dust or occasional condensation. Wire sizing: the spring-loaded terminals accept 2x (0.25 to 2.5 mm²) solid or stranded, or 2x (24 to 14 AWG) for the main contacts. For type 2 coordination (no-weld on short circuit), the required upstream fuse is gL/gG 20 A. The coil operates at 50/60 Hz with a voltage tolerance of 0.8 to 1.1 times rated at 50 Hz and 0.85 to 1.1 at 60 Hz — so a 110 V coil will pick up reliably down to about 88 V at 50 Hz.