Siemens 3RT2024-2BW40 — SIRIUS Power Contactor, 48 VDC Coil, Spring Terminals
Its 48 VDC coil is rated for pickup at 80% of rated voltage, with dropout between 15 and 18 ms — a tight window that keeps the contactor from chattering on a sagging DC bus.
Switching Duty and Thermal Limits
Rated for 1000 operations per hour in AC-1 (resistive), AC-2 (slip-ring motor), AC-3 (squirrel-cage motor starting), and AC-3e duty. AC-4 (plugging/inching) is derated to 300 ops/h — the arc energy from reversing or jogging builds heat faster than the S0 frame can shed. The thermal overload factor is set at 1.1 times full-scale, meaning the associated overload relay should be sized at 110% of motor FLA for standard starting.
The 45 mm width and 102 mm height fit standard S0 footprint; the 107 mm depth includes the spring-terminal projection.
Auxiliary Contact and Coil Ratings
The contactor ships with an auxiliary switch block integrated. The DC coil's switching capacity at various voltages is specified: 10 A at 24 V, 2 A at 48 V, 2 A at 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. Arcing time is listed at 10 ms — a consistent value that helps in coordinating upstream fuse or breaker clearing times.