SIRIUS S0 Power Contactor, 24 V DC Coil
The Siemens 3RT1026-1BB40 is a SIRIUS S0 power contactor with a 24 V DC coil drawing 5.4 W during both closing and holding, so the coil driver sees a constant load — no inrush peak to design around. It switches motor loads in AC-2 duty up to 11 kW at 400 V (per) and handles AC-4 reversing or inching at 15.5 A at 400 V (per). The IP20 front enclosure keeps live parts behind the panel door; the terminal area is rated IP00, meaning the wiring compartment expects enclosure protection from the cabinet.
Mounting and Panel Integration
Mounts via screw or snap-on onto 35 mm DIN rail per DIN EN 50022. The 45 mm width fits standard S0 contactor spacing; side-by-side mounting is permitted, so multiple contactors pack tightly on the rail without derating for proximity. Pollution degree 3 means it's rated for conductive pollution typical in industrial control panels — no conformal coating required for the contactor itself, though the cabinet environment must stay within the -25 to +60 °C operating range.
Termination and Wiring
Screw-type terminals on both the main current circuit and the auxiliary/control circuit. Main terminals accept 2x (1... 2.5 mm²) solid or stranded, 2x (2.5... 6 mm²), or max 2x 10 mm²; auxiliary terminals accept 2x (0.5... 1.5 mm²), 2x (0.75... 2.5 mm²), or max 2x (0.75... 4 mm²). AWG equivalents for main are 2x (16... 12), 2x (14... 10), 1x 8; for auxiliary, 2x (20... 16), 2x (18... 14), 1x 12. These ranges cover standard panel wire sizes without needing ferrules, though ferruled stranded is fine.
Coordination and Protection
For type 2 coordination (no weld risk on short circuit), the required upstream fuse is gL/gG 35 A. For type 1 coordination (contactor may be damaged but no fire risk), the fuse can be gL/gG 100 A. These are the manufacturer's specified limits — the panel designer sizes the branch protection accordingly. The AC-12 maximum operational current is 10 A, which governs resistive load switching on the auxiliary contacts.
Auxiliary Contact Ratings
The auxiliary contact block (integrated or add-on) is rated for DC switching at 24 V: 10 A; 60 V: 2 A; 110 V: 1 A; 220 V: 0.3 A. AC ratings at 230 V: 6 A; 400 V: 3 A; 500 V: 11 kW; 690 V: 11 kW. These are the contact ratings, not the coil — the coil is fixed at 24 V DC.