Solid-state overload relay for motor protection
The Siemens 3RB2036-2QB0 is a SIRIUS solid-state overload relay for three-phase motor circuits. This unit mounts directly onto a contactor (fastening method: contactor mounting), saving DIN-rail space in the panel. The 55 mm width and 92 mm height keep the footprint compact for a 3-pole device. Depth is 109 mm, which matters when planning gland-plate clearance or enclosure depth.
Auxiliary contact ratings and control circuit
The auxiliary and control circuit uses screw-type terminals accepting 0.5 to 4 mm² solid or 2x (0.5 to 2.5 mm²) stranded. The auxiliary contact ratings are voltage-dependent: 4 A at 120 V, 3 A at 230 V, 2 A at 24 V, 0.55 A at 60 V, 0.3 A at 110/125 V, and 0.11 A at 220 V. These cover most PLC input and contactor coil interface voltages, but verify the specific switching voltage against your control transformer — the 24 V DC rating of 2 A is adequate for typical relay coil loads.
The 3RB2036-2QB0 carries ATEX Type of Protection PTB 06 ATEX 3001 Ex II (2) GD, certifying it for use in potentially explosive atmospheres — specifically as a protective device associated with equipment in Zone 1/21 (gas/dust) areas. Surge voltage resistance is rated at 6 kV, and EMC immunity includes 2 kV burst on power ports and 1 kV on signal ports per IEC 61000-4-4, severity level 3. The substance prohibition date of 07/01/2006 aligns with RoHS compliance scope.