SIRIUS 3RT2028-1AV04 — size S0 power contactor, 34 A at 480 V
The Siemens 3RT2028-1AV04 is a SIRIUS power contactor in the S0 frame size, rated 34 A at 480 V. That 34 A figure is the AC-3 motor-switching current — the rating that governs real motor loads, not the higher resistive-heating number. Screw-type terminals on the coil, screw and snap-on mounting onto 35 mm DIN rail per DIN EN 60715. Panel builders will find the 45 mm width fits standard S0 busbar spacing; the 141 mm depth leaves clearance for front-of-panel wiring ducts.
Mounting and wiring — DIN rail, conductor range, spacing
Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the contactor sits in a swing-frame panel or a tight enclosure corner. Solid or stranded conductors from 1 to 10 mm² accepted at the main terminals; for the coil circuit, two conductors per clamp from 0.5 to 2.5 mm². Minimum air clearance: 10 mm upwards, downwards, and forwards; 6 mm at the sides. That 6 mm side gap is tighter than some S0 peers — check side-by-side spacing if you are packing multiple contactors on a DIN rail without separators.
Thermal limits and operating envelope
Operating ambient -25 to +60 °C; storage range -55 to +80 °C. Lifecycle status is current production.
Switching frequency and mechanical endurance
Rated switching frequency: 1 000 cycles/hour at AC-1 (resistive), 750 cycles/hour at AC-2 and AC-3 (motor starting and running), 250 cycles/hour at AC-4 (plugging/inching). The AC-4 limit is the one that catches people — if you are jogging or reversing a load frequently, the contactor needs to be sized for that duty class, not the AC-3 number. Mechanical life typical is 10 million operations; the arcing time on opening is 10 ms, which is tight enough for most coordination studies with upstream motor circuit protectors.