The Siemens 3RB1246-1EB00-0FM0 is a solid-state overload relay from the SIRIUS 3RB1 family, rated for motor protection from 25 A up to 100 A. It integrates thermistor (PTC) protection directly — no separate module needed — and adds ground-fault monitoring through an external summation current transformer. The relay provides one normally-open and one normally-closed contact for overcurrent/thermistor trips, plus a second NO/NC pair dedicated to ground-fault events. The monostable output means the relay resets automatically when the fault clears and the coil supply (DC 24 V) is maintained.
Deployment context
The 25-100 A range covers most IEC frame-size motor starters up to about 45 kW at 400 V. The DC 24 V control supply is common across modern PLC and safety-relay outputs, so it drops into an existing 24 VDC control bus without an extra power supply.