SIRIUS Size S00 power contactor — 4 NO, 110 VDC coil
The Siemens 3RT1316-1BF40 is a SIRIUS power contactor in the Size S00 frame, with four normally-open main contacts and a 110 VDC coil. It mounts via screw and snap-on onto a 35 mm DIN rail per EN 50022, fitting a 45 mm wide panel slot. The front and terminals carry IP20 protection — fine for a clean, enclosed control panel, but not for washdown or outdoor exposure.
Ratings and what they mean for your circuit
Rated for AC-2 duty at 400 V at 4 kW, this contactor handles wound-rotor motor loads where the current stays below the make/break stress of a standard AC-3 contactor. The 4 NO main contact arrangement gives you four independent power poles — useful for switching multiple load circuits or a star-delta configuration without adding auxiliary contact blocks. At 24 VDC the contactor switches 10 A; at 110 VDC it switches 1 A; at 220 VDC it switches 0.3 A. Those DC ratings are the ones to check if you're breaking DC loads — the arc extinction is different from AC, and these numbers are the limit. The coil holds at 110 VDC nominal, with a pick-up threshold of 0.85 x rated voltage and a drop-out of 1.1 x rated voltage. Closing power is 3.3 W DC; holding power is the same 3.3 W — a DC coil that doesn't reduce power after pull-in, so the coil stays warm. Verify your control transformer can supply the inrush without sagging below 93.5 VDC. Ambient operating range is -25 to +60 °C, with pollution degree 3 (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation). That's typical for industrial control panels not in a sealed, climate-controlled room. Maximum operating altitude is 2 000 m without derating. For type 2 coordination ('no damage' after a short-circuit fault), the required upstream fuse is gL/gG 20 A. For type 1 coordination (device may be damaged but no fire risk), it's gL/gG 35 A. Wire the main circuit with screw terminals accepting 2x (0.5 to 1.5 mm²) solid, 2x (0.75 to 2.5 mm²) solid, or up to 2x (0.75 to 4 mm²) stranded with ferrules.