Siemens 3RU5156-3HB2 — SIRIUS Thermal Overload Relay, 90–120 A, Class 10, Size S6
Siemens SIRIUS thermal overload relay, 90–120 A, class 10, size S6, 3-pole, screw terminals for main and auxiliary circuits, manual/auto reset.
Class 10 means the relay must trip within 10 seconds at 7.2× the current setting (per IEC 60947-4-1). That is the standard for standard-duty motor starting — it clears before the motor windings overheat on a locked-rotor condition, but it is not as fast as class 5 (for submersible pumps) or as slow as class 20/30 (for high-inertia loads like crushers). For a general-purpose conveyor or fan drive, class 10 is the usual specification. It will hold up against switching transients from contactors and drives on the same bus. The operating frequency range of 50–60 Hz covers both common line frequencies worldwide. No derating needed between the two — the bimetallic strip responds to RMS heating current, not frequency.
Size S6 device mounts directly to a SIRIUS contactor of the same frame or standalone on a mounting plate. Screw terminals on main circuit accept lug or ring-tongue terminations for 90–120 A power conductors.
Lifecycle stage is current. Substance prohibitance date 09/03/2013 aligns with RoHS compliance deadline.