The Siemens 3RT1934-5AD01 is a SIRIUS magnet coil designed for size S2 contactors, with a 42 V AC control supply at 50 Hz and screw-type terminals. This is a phased-out product; the official successor is the SIRIUS 3RT2 series.
What the ratings mean for fit
The coil operates at 42 V AC, 50 Hz, with an operating range of 0.8 to 1.1 times the rated voltage — meaning it picks up reliably between about 33.6 V and 46.2 V. That tolerance matters when the control transformer is loaded or the line sags; if your panel's control voltage sits at 48 V or above, this coil may not drop out cleanly. The screw terminal matches the size S2 contactor footprint — no adapter needed, but verify the existing coil's voltage and frequency before swapping.