The Siemens 3RB1246-1EB40 is an overload relay with an analog output, setting range 25-100 A, 24 V DC coil. It protects motors from overcurrent and phase failure by monitoring the current draw and providing a proportional analog signal (typically 4-20 mA or 0-10 V, depending on the variant) back to a PLC or drive controller for load tracking or predictive maintenance. The 25-100 A range covers a wide band of medium-horsepower induction motors — think 15 to 55 kW at 400 V — so it fits pump, fan, and conveyor applications where you want both protection and process feedback from a single device.
The analog output wiring runs to a PLC analog input card; the 24 V DC coil supply is separate from the motor power circuit. Keep the analog signal cable away from the motor cable to avoid induced noise — shielded twisted pair, grounded at the PLC end, is standard practice.