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.
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.
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.
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.