Siemens 3RV1901-1D NQ030131 Relay

Siemens 3RV1901-1D NQ030131 is a Sirius Classic auxiliary contact (one changeover contact) designed for front‑mount installation on the SIRIUS 3RV1 motor starters, providing a single CO output to accompany the main protection circuit. It is specified for circuit-breaker size S00 and is mounted on the front of the device to integrate with compact control panels. This part has been discontinued, with Siemens listing 3RV2901-1D as the preferred successor for the Sirius family. In typical panel setups, the auxiliary contact is used to signal the status of the main device or to interlock related control circuits in small‑format motor‑control applications.