The Siemens SIRIUS 3RT1934-5AV01 is a magnet coil for Size S2 contactors, rated 400 V AC at 50 Hz with a voltage tolerance of 0.8 to 1.1 times the rated value. It uses screw terminals for the control circuit connection.
The 0.8 to 1.1 tolerance (320 V to 440 V) means the coil will pick up and hold across a typical AC line sag, but a sustained drop below 320 V risks dropout — important for brownout-prone sites. The screw terminal connection matches standard panel wiring practice; no special tooling needed.