Integrator note — SIRIUS S0 contactor, 24 VDC coil
The Siemens 3RT2024-2AP00 is a SIRIUS power contactor in the S0 frame, designed for switching loads up to 18 A (AC-3) or 8 A (AC-4) on the main contacts. Spring-type terminals on the coil accept solid or stranded wire 1–10 mm² and dual 0.5–2.5 mm²; strip length and ferrule sizing follow standard practice, but the spring cage needs a clean insertion — no whiskers.
DC switching — the real curve
This contactor carries a DC-1 rating of 10 A at 24 V, but the DC switching capacity drops fast as voltage rises: 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V. The 0.6 A at 440 V and 11 A at 480 V are AC ratings — don't confuse them with DC. For DC loads, the arcing time is 10 ms, and the maximum switching frequency is 1000 cycles/hour for AC-1/2/3 (–), dropping to 300/h for AC-4. If you're switching a DC motor or solenoid, derate per the voltage curve and add a free-wheel diode across the coil.
Dimensions: 45 mm wide, 102 mm high, 97 mm deep. The auxiliary switch is included.