The Siemens SIRIUS 3RT6916-1BB00 is a varistor-type surge suppressor designed for motor contactors and contactor relays in the S00 frame size. It clips directly onto the contactor coil terminals — no additional wiring or panel space beyond the 9 mm depth it adds to the device stack. The suppressor is rated for control supply voltages of 24...48 V AC at both 50 Hz and 60 Hz, and 24...70 V DC, covering the common control-voltage range for SIRIUS S00 contactors across AC and DC coil variants.
The width (28 mm) and height (46 mm) match the S00 contactor footprint, so the assembly stays within the same envelope as the base device. The clip-on fastening method means no tools are needed for installation or replacement; the suppressor snaps onto the contactor's coil terminals and is held by spring tension. The varistor design clamps voltage transients generated when the contactor coil de-energizes, protecting nearby PLC outputs, relays, and other sensitive control electronics from inductive kickback.
The part is RoHS-compliant with a substance prohibition date of May 1, 2012, and falls under the SIRIUS brand's standard documentation package (CE, UKCA, EAC, and UL/CSA approvals typical for this series — verify specific certs against the project's jurisdiction).