Its rated voltage at 50 Hz is 380 V, and the coil holds within a voltage tolerance band of 0.8 to 1.1 times the rated value — meaning the contactor will pick up and stay sealed as long as the control voltage stays between roughly 19 V and 26 V AC. That tolerance is what governs reliable switching on a line with a sagging or lightly loaded transformer.
Integration note
As a SIRIUS-series magnet coil, this part snaps onto the contactor's coil terminals — no separate DIN-rail footprint. The AC control supply type means the coil impedance is designed for sinusoidal voltage; verify the control transformer sizing if the circuit also powers DC loads, since shared rectifiers can distort the waveform and reduce the effective holding voltage below the dropout threshold.