The Siemens SIRIUS 3RT2627-1BB45 is a capacitor contactor — a switching device designed specifically for making and breaking capacitor banks in power-factor correction panels. The coil is 24 VDC, terminated with screw-type terminals. At 45 mm wide, 135 mm tall, and 165 mm deep, it fits into standard distribution enclosures alongside other S0 contactors and overload relays.
Capacitor contactors must handle inrush currents that can exceed steady-state by tens of times. The 3RT2627-1BB45 is rated for switching at 24 VDC up to 6 A, at 60 VDC up to 2 A, at 110 VDC up to 1 A, at 125 VDC up to 0.9 A, at 220 VDC up to 0.3 A, at 230 VDC up to 6 A, at 400 VDC up to 3 A, and at 690 VDC up to 1 A. These are the DC-1 (resistive) or DC-3 (motor/capacitor) switching currents — the numbers you use to size the contactor for your bank's discharge and re-energization cycle. The contactor's arcing time is 10 to 10 ms, and the opening/closing time at DC is 15 to 18 ms. That repeatable timing matters when synchronizing multiple capacitor steps in a PFC controller.
Terminals accept solid conductors: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm². Stranded: 2x (1 to 2.5 mm²) or 2x (2.5 to 10 mm²). At 40 °C ambient, a single 10 mm² conductor is allowed; at 60 °C, two 10 mm² conductors. Maximum switching frequency is 100 operations per hour at voltages up to 600 VAC, dropping to 72 operations per hour at 690 VAC. That sets the cycling limit for your capacitor bank's daily switching schedule.