The Siemens 3RB2036-2UX1 is a SIRIUS solid-state overload relay for three-phase motor protection, rated CLASS 20E trip class. It provides motor overload and phase-loss protection for induction motors, with a single NC (normally-closed) auxiliary contact for fault signaling. The relay is approved for ATEX Ex II (2) GD, meaning it can be used in potentially explosive atmospheres where gas and dust are present, per the PTB 06 ATEX 3001 certification.
The CLASS 20E trip class means the relay allows a 20-second thermal overload before tripping at 7.2× rated current — suitable for standard motor start profiles where the inrush does not exceed that window. For auxiliary contact switching, the NC contact is rated 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, covering typical PLC input or contactor coil circuits. The 6 kV surge voltage resistance (IEC 61000-4-5) and 2 kV burst immunity on power ports (severity 3) ensure the relay holds up in industrial panels with switching transients.
The main current circuit uses straight-through transformers; auxiliary and control connections are spring-loaded terminals accepting 2x (0.25...1.5 mm²) solid or finely stranded wire (AWG 24...16). Shock rated 15g / 11 ms.