Capacitor switching contactor — what it does and where it fits
The Siemens 3RT2626-1AP65 is a SIRIUS series capacitor contactor, size S0, designed specifically for switching capacitor banks in power factor correction (PFC) applications. Unlike a standard motor contactor, it includes pre-charge resistors and a dedicated switching sequence that limits inrush current when energising a discharged capacitor — preventing contact welding and nuisance fuse trips.
Switching ratings across the voltage range
These are the currents the contactor can make and break for capacitor loads — the values drop at higher voltages due to the increased stress on the arc-quenching system. Maximum switching frequency is 100 operations per hour across the entire voltage range from 230 V to 690 V — this is the thermal limit of the pre-charge circuit, not the main contacts. The arcing time is a tight 10 ms, and the total switching time (including pre-charge) is 4 to 16 ms at AC, ensuring fast capacitor engagement without prolonged arc energy.
Termination and conductor sizing
The magnet coil uses screw-type terminals — the same termination style as the main power circuit. At 40 °C ambient, a single 10 mm² conductor is permitted; at 60 °C, two 10 mm² conductors are required to handle the same current with the higher temperature derating. No attachable auxiliary contact blocks are fitted as standard (0 auxiliary contacts) — the contactor ships as a bare capacitor-switching device. If auxiliary signalling is needed, the S0 frame accepts the standard SIRIUS auxiliary contact block range, which must be ordered separately.
Environmental limits and coil data
Lifecycle status is current production — the 3RT2626-1AP65 remains an active catalogue item from Siemens.