The Siemens 3RT1627-1AR61 is a capacitor contactor from the SIRIUS family, designed specifically for switching capacitor banks in power-factor correction (PFC) applications. Its AC-6 duty rating of 25 kVAr at 400 V means it handles the inrush currents and transient stresses that come with energizing a capacitor bank — a standard power contactor would weld its contacts under that surge. The 35 A AC-1 rating covers resistive loads if the same contactor is used for bypass or discharge duties. That is a fixed-voltage coil — no electronic wide-range coil here — so verify your control voltage matches before wiring. The contactor carries 3 normally-open main poles and 1 normally-open auxiliary contact, enough for a basic capacitor-step control with a feedback signal to the controller.
Mounting and integration — panel fit
Dimensions are 135 mm deep, 45 mm wide, 100 mm tall. Side-by-side mounting is allowed, saving panel width when stacking multiple capacitor steps. That means the operator interface is finger-safe, but the wiring zone is not — the panel builder must provide a cover or enclosure over the terminals to meet touch-safe requirements.