What it is and what it does
The Siemens 3RT1936-1ER00 is a SIRIUS surge suppressor with diode assemblies, designed for 24 V DC control supply voltage. It suppresses the inductive kickback from a contactor coil when de-energized, protecting nearby electronics and prolonging contact life. This part physically mounts onto SIRIUS contactors in Size S2 and S3 — the larger frame sizes in the SIRIUS family, used for higher-current motor and resistive loads in control panels.
Sourcing and lifecycle reality
The 3RT1936-1ER00 is marked as a phased-out product. The official SIRIUS 3RT2 preferred successor is the 3RT2936-1ER00, which shares the same diode design and 24 V DC rating but is built for the current 3RT2 contactor platform. For existing BOM lines that specify this exact order code, the 3RT1936-1ER00 is sourced to order against an RFQ through independent channels. Availability is confirmed per inquiry.
What the ratings mean for fit
Rated for 24 V DC only — the diode assemblies are polarity-sensitive, so verify the control circuit orientation before installation. Installing on an AC coil will not suppress correctly and may damage the diode stack. The suppressor clips directly onto the contactor's coil terminals, adding minimal depth to the existing DIN-rail assembly. No additional wiring or enclosure space is needed beyond the contactor footprint.