What it is and what it does
The Siemens 3RT7026-1AG05 is a size S0 contactor from the SIRIUS family, with three main poles and three normally-open main contacts. It is rated for AC-3 duty up to 690 V, meaning it is designed to switch three-phase motor loads in control panels — the AC-3 rating is the one that governs real motor switching, not the thermal current. It mounts on a 35 mm DIN rail per DIN EN 50022, using either screw fixing or snap-on. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, which gives panel builders flexibility in tight enclosures. The front and terminal areas carry an IP20 rating, so it is protected against finger contact but not against moisture or dust ingress — it belongs inside a panel, not in a washdown zone.
Key ratings and what they mean for fit
The AC-3 maximum operating voltage is 690 V, and the contactor is also rated for DC-13 at 220 V (0.3 A), so it can switch DC control loads as well, though the DC current is limited. Operating temperature range is -10 to +55 °C, storage from -25 to +70 °C. With degree of pollution 3, it is suited for industrial environments where conductive dust or condensation may be present — typical for a panel in a factory hall. The coil draws 0.82 W on closing and 0.24 W holding (DC), so the holding power is low — a detail that matters for control transformer sizing and heat buildup in a dense panel. Auxiliary contacts are rated for PLC-level signals (17 V, 5 mA), meaning they are reliable down to low-energy logic levels — the operator will find the bug at 2 a.m. if the auxiliary contacts don't wet, but these are specified to handle it.
Sourcing and lifecycle
For a BOM freeze or a line-down replacement, the part is sourced to order against an RFQ. The screw-type terminals on both main and auxiliary circuits match the wiring practice of existing SIRIUS panels — no tooling change needed.
Integration notes
Dimensions: 55 mm wide, 85.5 mm high, 91 mm deep. The S0 frame size is a standard footprint in the SIRIUS range, so it fits alongside overload relays and other S0 accessories on the same DIN rail. Side-by-side mounting is permitted, which saves panel width when multiple contactors are ganged. Fuse coordination: for type 2 coordination, use a 35 A gL/gG NH 3NA fuse; for type 1, an 80 A fuse. This is the spec the panel designer needs to hand to the wireman. Screw terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded, and the same for finely stranded with ferrules.
Compliance and documentation
The contactor carries a rated surge voltage resistance of 6 kV and an insulation voltage of 690 V. The evidence does not list specific UL, CSA, or CE marks, but as a Siemens SIRIUS part, it is typically certified to IEC/EN 60947-4-1 and carries CE marking for the European market. RoHS and REACH documentation is available from Siemens upon request.