SIRIUS 3RU2146-4MB1 — Thermal Overload Relay, Size S3, Class 10
The Siemens 3RU2146-4MB1 is a SIRIUS-brand thermal overload relay, Size S3, Trip Class 10. Rated for main circuit voltages up to 690 V, the relay handles 45 kW at 400 V (AC-3e duty) and 90 kW at 690 V. The size S3 frame and screw-type terminals accept solid conductors up to 16 mm² and stranded up to 70 mm², suiting it for motor branch circuits in the 30–100 A range. Mount in any position on a flat panel or DIN rail via stand-alone installation. The relay includes a trip-indicator flag and a "Tripped" message contact for remote signaling — useful for a PLC or HMI to log the fault without sending someone to the cabinet.
Current Production — Sourcing This Part
Substance prohibitance per RoHS is recorded with a date of 03/01/2017, confirming compliance with the EU RoHS directive.
Auxiliary Contact Ratings and Wiring
The auxiliary contact block carries 2 A at 24 V, 3 A at 120 V, and 0.75 A at 690 V — enough to drive a PLC input or a small contactor coil directly. At 24 VDC the 2 A rating is the limiting case for inductive loads; verify the inrush of the driven device stays under that. Terminals accept solid 2x (0.5–1.5 mm²) or stranded 2x (0.75–2.5 mm²) for the control circuit. Main circuit terminals use M8 bolts with a 4 mm hex socket driver.
Temperature Compensation and Environmental Range
The relay compensates for ambient temperature changes across -40 to +60 °C, maintaining accurate trip timing without manual adjustment. Power dissipation per pole is 7 W at rated current — account for this heat in a densely packed enclosure to avoid derating adjacent devices.