The Siemens SIRIUS 3RT7916-1CE00 is an RC-type surge suppressor designed to clip directly onto S00-frame contactors in the 3RT7 series. It suppresses voltage spikes across the coil when the contactor de-energizes, protecting nearby PLC outputs and reducing electromagnetic interference on the control wiring.
The suppressor clips onto the contactor coil terminals — no DIN-rail space consumed, no additional wiring required. At 9 mm depth, 28 mm width, and 46 mm height, it adds negligible projection beyond the contactor body itself. Mounting position is unrestricted, so it fits equally well in vertical or horizontal panel layouts.
Compliance documentation is in order: RoHS and REACH substance prohibitance dated June 15, 2022, confirming it meets current EU substance restrictions.
What the RC element means for the control circuit
The RC (resistor-capacitor) design is a passive snubber that limits the voltage rise rate across the contactor coil when switched off. This prevents the inductive kick from exceeding the rated impulse withstand of solid-state outputs on a PLC or safety relay module — a common failure mode when a bare coil is driven directly. Because it is a dedicated RC element rather than a varistor or diode, it works with AC coils only — no polarity concern, and it does not delay the dropout time of the contactor, which matters for safety circuits that rely on fast opening of the main contacts.