The Siemens SIRIUS 3RT1934-5AP01 is a replacement magnet coil for Size S2 contactors in the SIRIUS family, wound for 230 V AC control supply at 50 Hz. It terminates through screw terminals and is the coil you'd swap when the original contactor's electromagnet fails or the control voltage changes. The operating range at 50 Hz holds between 0.8 and 1.1 times the rated voltage, so it'll pick up reliably even if the line sags a bit, but won't drop out on a mild brownout.
What It Fits and How It Mounts
The coil is sized for SIRIUS Size S2 contactors. Mounting is straightforward — the coil snaps onto the contactor's magnet stack and the screw terminals accept the control wiring. The contactor itself mounts onto a 35 mm DIN rail per EN 50022, so the whole assembly integrates into a standard control panel. The IP20 finger-safe protection on the front of the contactor carries through; the coil itself is inside the contactor envelope, so it's not exposed to washdown or dust ingress.
Voltage and Duty Considerations
Rated for 230 V AC control supply only — this is not a dual-voltage or DC coil. The AC pick-up power is higher than the holding power (a standard AC coil characteristic), so the control transformer feeding it needs to handle the inrush without dropping below the 0.8x pick-up threshold. If your panel runs on 60 Hz, this coil is specified for 50 Hz only; you'd need the 60 Hz variant for reliable operation on a 60 Hz line.