The Siemens SIRIUS 3RT1916-1PB2 is an EMC suppression module designed to clamp voltage transients on the coil of a Size S00 contactor. This module snaps onto the contactor's coil terminals, so it adds no DIN-rail footprint and no extra wiring; the suppression is in the same physical envelope as the contactor itself.
Lifecycle and replacement path
The 3RT1916-1PB2 is a phased-out product. Siemens lists the preferred successor as the SIRIUS 3RT2916-1PB2, which drops into the same Size S00 contactor footprint and performs the same varistor-based surge suppression at 575 V AC. For new designs, the 3RT2916-1PB2 is the direct drop-in replacement.
What the 575 V rating means for fit
The 575 V AC rating at both 50 Hz and 60 Hz means this module is sized for 480 V / 575 V three-phase systems common in North American and Canadian industrial panels — it clamps the coil's turn-off spike to a level that stays within the contactor's insulation coordination. The varistor design handles the repetitive energy of a contactor coil without degrading over the mechanical life of the contactor. If your panel runs 400 V AC line-to-line, this module still works; the clamping voltage is above the peak of 400 V, so it only conducts during the transient, not during normal operation.
The module mounts directly onto the coil terminals of a SIRIUS Size S00 contactor (e.g., 3RT1016 or 3RT1024 series). No DIN-rail space is consumed, and no additional wiring is needed beyond the coil connections. The varistor is encapsulated, so it meets the same pollution degree and clearance requirements as the contactor itself. Verify that the contactor's coil voltage matches the module's 575 V AC rating — this is not a universal-voltage suppressor.