The Siemens SIRIUS 3RT5936-1ER00 is a diode-combination surge suppressor designed to mount directly onto a SIRIUS contactor coil. It suppresses the inductive voltage spike when the DC coil de-energizes, protecting the control-circuit contacts and the PLC output driving it. Rated for 24 V DC control supply voltage, it is a drop-in accessory for any SIRIUS contactor in that coil-voltage range.
The 24 V DC rated value is the coil voltage it matches — not a range, not a universal DC voltage. If your contactor coil is 24 V DC, this suppressor is the correct part. The diode combination design means polarity matters: install it with the correct orientation relative to the coil's DC supply, or the diode blocks rather than suppresses. Storage range of -40 to +80 °C is wider — fine for spares stored in a warehouse or truck during transport.