What it is and what it does
The Siemens 3RT1916-1LN00 is a DC surge suppressor with a built-in diode and LED indicator, designed to clamp the inductive kickback from a contactor coil when it de-energizes. Without this suppression, the voltage spike can damage PLC outputs, relay contacts, or the coil driver circuit. The LED gives a quick visual that the coil circuit is live. It operates across a 70 to 150 V DC control supply range, so it matches any nominal DC coil voltage within that band — 110 V DC, 125 V DC, or a 48 V DC coil on a higher-voltage bus. The diode must be polarity-sensitive; verify the DC rail orientation before installation.
Mechanical fit and mounting
This suppressor clips directly onto the front of a Siemens SIRIUS S00 contactor — no wiring changes needed beyond plugging it into the coil terminals. That makes it a drop-in upgrade or replacement for any S00 contactor already in the panel that lacks a factory-fitted suppressor. The S00 frame size covers the 3RT1 and 3RT2 contactors up to about 7 A motor load. If your panel uses an S0 or larger contactor, this suppressor won't physically mate — you need the S0 version (3RT2916-1LN00 is the successor for that frame as well).
Lifecycle and sourcing reality
The 3RT1916-1LN00 is a phased-out product. The official Siemens successor is the 3RT2916-1LN00, which covers the same function and voltage range for S00 contactors. If you're holding a BOM line for the 3RT1916, the 3RT2916 is the direct drop-in replacement — same mounting, same wiring, same suppression characteristics. For legacy installations where the panel was built around the 3RT1916 and you need a one-for-one spare without requalifying a new part number, we can source the phased-out 3RT1916-1LN00 through our network. Submit an RFQ with your quantity and target delivery window.