The Siemens 3RT1916-1BD00 is a SIRIUS varistor surge suppressor designed to clip voltage transients across the coil of size S00 contactors. It's the kind of part you bolt onto a contactor in a control panel to keep inductive kick from taking out the PLC output or the DC supply — a cheap insurance piece that saves an up-tower swap or a line-down callout. Rated for 127...240 V AC at 50 Hz and 240...127 V AC at 60 Hz, plus 150...250 V DC. That dual AC/DC rating means it covers both common control voltages — a 230 V AC coil on a motor starter or a 24 V DC relay coil — though the DC range starts higher than standard 24 V, so it's really aimed at the 110-220 V DC bus side.
Sourcing & Lifecycle Reality
No last-time-buy window remains; it's a find-and-supply posture.
The AC voltage range (127...240 V at 50 Hz) is the standard European control voltage band — it matches a 230 V contactor coil directly. The 60 Hz range (240...127 V) covers the North American 240 V control bus. The DC range (150...250 V) suits higher-voltage DC link circuits, not 24 V DC. If your control voltage is 24 V DC, this suppressor won't clamp — its threshold is above that. The varistor design means it absorbs energy from each switching event and degrades slightly over time. In a high-cycling application (frequent start/stop on a conveyor or a compressor), you'll want to budget for replacement every few years. The 3RT2916 successor uses the same varistor technology, so the same consideration applies.
Panel Integration
Mounts directly onto SIRIUS S00 contactors — snaps on without tools, no extra wiring space needed. The contactor's coil terminals accept the suppressor leads; no DIN rail space consumed. If you're retrofitting an existing panel, just clip it onto the contactor and land the two wires.