Capacitor switching contactor, S3 frame, 110 V AC coil
The Siemens 3RT2646-1AF05 is a SIRIUS capacitor contactor in the S3 size class, designed specifically for switching capacitor banks in power factor correction (PFC) applications. It carries a 110 V AC 50 Hz coil with screw-type terminals.
Switching frequency and thermal limits
Maximum switching rate is voltage-dependent: 150 operations per hour at 230/240 V, 80 ops/h at 400 V, and 30 ops/h at 690 V — the capacitor discharge time between cycles governs the limit, not the contactor's mechanical life. At 40 °C ambient, a single 70 mm² conductor is sufficient; at 60 °C, two 50 mm² conductors in parallel are required to carry the same current without exceeding the terminal temperature rise.
Mounting and auxiliary contact provisions
Accepts one attachable auxiliary contact block (screw-type), expanding the switching functionality for status feedback or interlocking in the capacitor bank controller circuit. Dimensions: 80 mm wide, 140 mm high, 152 mm deep — the S3 frame footprint is standard across the SIRIUS contactor family, so panel cutouts and busbar layouts transfer if you swap between a standard motor contactor and this capacitor-rated variant.