What the 81 A Minimum and Trip Class Mean for Your Motor
The Siemens 3RW5236-2TC15 is a SIRIUS soft starter with an 81 A minimum setting — that's the smallest motor current it can protect, not the maximum. The trip class defaults to CLASS 10A per IEC 60947-4-2, meaning it clears a stalled or jammed rotor fast enough to keep the motor winding insulation from cooking. You can also select CLASS 10E or 20E for applications where a longer acceleration ramp is needed, like high-inertia loads. The rated supply voltage spans 200 to 600 V, which covers most three-phase industrial mains, and the control supply accepts 110 to 250 V at both 50 and 60 Hz.
Fieldbus Fit: Modbus, PROFINET, EtherNet/IP, PROFIBUS
This soft starter speaks Modbus RTU, Modbus TCP, PROFIBUS, PROFINET, and EtherNet/IP out of the box — no separate communication module needed for most networks. That makes it a straight drop into a Rockwell, Siemens, or Schneider control architecture without a protocol gateway. The PROFINET interface also supports PROFIenergy, so you can shut down the motor during idle periods and log energy data through the automation controller.
Mount it on a vertical surface with screw fixing — the enclosure can rotate ±90° and tilt ±22.5° front-to-back, which helps when the panel layout is tight. Clearance: 100 mm above, 75 mm below, 10 mm front, 5 mm sides, and 0 mm rear. During operation it handles -25 to +60 °C, but you'll need to derate above 40 °C. Shock-rated to 15 g for 11 ms, so it survives the vibration on a pump skid or conveyor line.