What it is and what it does
The Siemens 3RT1026-3AP00 is a SIRIUS power contactor in the S0 frame size, designed for switching three-phase motor loads in industrial control panels. It carries 3 NO main contacts and is rated for 11 kW at both 500 V and 690 V, making it suitable for 400 V-class motors up to that power level in standard AC-3 duty. For demanding applications like reversing, inching, or plugging, the AC-4 rating of 15.5 A at 400 V defines the switching capability under high electrical stress — this is the figure to check when the load sees frequent starts or reversals under full current.
Mounting and integration
Mounts via screw or snap-on onto a 35 mm DIN rail per DIN EN 50022. The S0 frame occupies 45 mm width, 85 mm height, and 90 mm depth — a compact footprint that leaves room for auxiliary contact blocks or overload relays on the same rail. Side-by-side mounting is permitted without derating, which simplifies multi-contactor panel layouts. Main circuit connections use screw-type terminals accepting 2x (1 to 2.5 mm²) solid/stranded, 2x (2.5 to 6 mm²), or up to 2x 10 mm² — or AWG equivalents 2x (16 to 12), 2x (14 to 10), 1x 8. The front face carries IP20 protection, while the terminal area itself is IP00, so maintain clearance around live parts inside the enclosure.
Coordination and protection
For Type 1 coordination (no damage to the contactor but may need contact replacement after a fault), use a gL/gG fuse rated up to 100 A. For Type 2 coordination (contactor remains fully operational after a fault), the fuse must be limited to 35 A gL/gG. These values govern the upstream short-circuit protection device selection. Rated for pollution degree 3, meaning it's suited for industrial environments where conductive pollution or dry non-conductive pollution that becomes conductive due to condensation occurs. Operating temperature range is -25 to +60 °C, with altitude limit of 2,000 m.
Auxiliary contacts and endurance
The integrated auxiliary contact block (1 NO + 0 NC) is rated for switching at various control voltages: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 2 A at 60 V, with lower ratings at 110 V (1 A) and 220 V (0.3 A). These cover typical PLC or relay interface signals. Mechanical endurance is rated at 10 million operating cycles typical.