Siemens SIRIUS 3RT2526-1BB40 — S0 frame contactor with 24 V DC coil
The S0 frame is the compact size in the SIRIUS contactor family, covering the lower current range up to about 40 A AC-3.
Switching capacity across voltage ranges
The contactor's switching capacity varies significantly with voltage and load type. At 230 V AC, it handles 10 A for resistive loads (AC-1). The arcing time is consistent at 10 ms across the operating range, and the DC switching delay (15–18 ms) means the contactor is suitable for moderate-speed DC applications but not for fast-switching DC loads where arc suppression is critical.
Its dimensions are 61 mm wide, 85 mm high, and 107 mm deep — the S0 footprint is standard across the SIRIUS range, so panel layouts designed for other S0 contactors accept this unit without modification. Clearance requirements are 0 mm in all directions except 6 mm at the sides, which simplifies panel layout in tight enclosures. This covers common control wiring sizes for 24 VDC circuits and motor power leads up to 2.5 mm².
For volume purchases or MRO spares, the part is available through independent distribution with full Siemens traceability. The S0 frame and 24 V DC coil are common configurations, so lead times are typically standard for the SIRIUS product family. The coil operates at 24 V DC with a pick-up voltage of 0.8× rated (19.2 V) and a drop-out voltage of 1.1× rated (26.4 V) — important for brownout conditions in 24 VDC control systems.