Siemens 3RU2136-4RB0: a 3RU2 thermal overload relay in size S2 with a setting range of 70 … 80 A and CLASS 10 tripping, built for contactor mounting. It has 1 NO + 1 NC auxiliary contacts: the NC contact opens the contactor coil circuit on overload and the NO contact can signal the trip to the PLC.
At 70 … 80 A this relay suits motors of roughly 37 kW at 400 V (per the Siemens AC-3 rating), but the setting must always follow the nameplate current, not the kW value.
See our Siemens industrial controls for matching 3RT2 contactors in size S2.
Technical data
| Siemens order number | 3RU2136-4RB0 |
|---|---|
| Product | SIRIUS 3RU2 thermal overload relay |
| Size | S2 |
| Current setting range | 70 … 80 A |
| Trip class | CLASS 10 |
| Auxiliary contacts | 1 NO + 1 NC |
| Rated operating voltage | 690 V |
| Motor power at 400 V (approx.) | 37 kW |
| Mounting | Contactor mounting (size S2) |
| FLA, 3-phase motor at 480 V (UL) | 80 A |
| Power loss (hot, total) | 18.9 W |
| Ambient temperature (operation) | -40 … +70 °C |
| Dimensions (W x H x D) | 55 x 90 x 105 mm |
| Net weight | 0.298 kg |
| Condition | New, original Siemens |
Typical applications
- Motor starters with SIRIUS 3RT2 contactors
- Replacement of an aged or damaged overload relay
- Pumps, fans and conveyors in water, HVAC and packaging plants
- Protection of motors with rated current 70 … 80 A
Compatibility and replacement
Plugs directly onto 3RT2 contactors of size S2 (3RT203x). For separate (stand-alone) mounting Siemens offers a terminal support. It replaces the earlier 3RU11 series of the same setting range; send us the old order number to confirm.
Frequently asked questions
Which contactor does it fit?
SIRIUS 3RT2 contactors of size S2.
What motor size does it suit?
Per Siemens the range corresponds to about 37 kW at 400 V (AC-3), but always set it by the motor rated current, not by the kW rating.
Can it be mounted on its own?
Yes, with the Siemens terminal support for stand-alone installation; otherwise it plugs straight onto the contactor.
Do you ship to my country, and what is the warranty?
Yes. RendatSP ships worldwide from Yiwu, China, by air in 5 to 7 days once the part is ready, and every part carries a 1-year warranty. Send the order number and quantity on WhatsApp and we will reply with a quotation.
How to order
Message us the order number and quantity. For breakdowns, tell us the delivery address and we will offer the fastest shipping option. If the exact part is discontinued, we confirm the official successor before quoting.
Every part RendatSP supplies is new and original, carries a 1-year warranty and ships worldwide by air in 5 to 7 days once ready (shipping, payment and warranty). Send us the order number and quantity on WhatsApp or through the inquiry form and we will quote the same working day. Agents in Saudi Arabia, Iraq, the UAE, Egypt, Oman, Libya, Morocco, Mauritania, Yemen, Algeria and Jordan.
