The Siemens 3RB1045-1EB0 is an electronic overload relay in the SIRIUS family, rated 25...100 A with Class 10 trip characteristic. It mounts directly to a contactor of the same size S3 frame, using screw connections and a manual-only reset. The Class 10 rating means it trips within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during a locked-rotor event without nuisance tripping on normal starts.
Deployment context
This relay is sized for the contactor-mount footprint (size S3), so it snaps onto the matching SIRIUS contactor without additional wiring between the relay output and the contactor coil — the load current passes through the relay's bimetallic or electronic sensing element, and the trip signal opens the contactor directly. The screw terminals accept the motor leads; no separate control wiring for the trip circuit is needed on this manual-reset variant.
Lifecycle and sourcing
The lifecycle stage for this order code is listed as current, meaning Siemens continues to manufacture and support the 3RB1045-1EB0 as an active catalog item. For a BOM line that specifies this exact relay, the part is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time.