Many installed machines still run on SIRIUS 3RV1 motor-protection breakers that were paneled up a decade or more ago. When one of these feeders trips and will not reset, the question is no longer about the latest catalog part: it is about finding a matching rating quickly so the line can restart. The Siemens SIRIUS 3RV1021-1JA15 (order number 3RV1021-1JA15) is a size S0 circuit breaker in that 3RV1 family, set for a 7 to 10 A overload range. It is a phased-out product, so this guide is written for the engineers and procurement teams who are still maintaining equipment built around it. It covers the verified ratings, how the S0 frame differs from the smaller S00 and the much larger S2 breakers, and the recognized successor.
What Is the 3RV1021-1JA15?
The 3RV1021-1JA15 is a three-pole motor-protection circuit breaker in the SIRIUS 3RV1 range, size S0. It combines a thermal overload release with a magnetic short-circuit release in one DIN-rail unit, and this specific variant is fitted with a transverse auxiliary switch offering one normally-open and one normally-closed contact (1 NO + 1 NC) for remote trip indication. Siemens has phased out the 3RV1 generation in favor of the SIRIUS 3RV2 range; the manufacturer-named successor for this rating is the 3RV2011-1JA15.
Verified Specifications
| Parameter | Specification |
|---|---|
| Order number | 3RV1021-1JA15 |
| Product family | SIRIUS 3RV1 motor starter protectors |
| Frame size | S0 |
| Design | Circuit breaker for motor protection, 3-pole |
| Overload release setting (Ir) | 7 ... 10 A, adjustable |
| Short-circuit release (magnetic) | 130 A |
| Tripping class | Class 10 |
| Rated permanent current (Iu) | 10 A |
| Typical motor power (AC-3, 400 V) | 4 kW |
| Rated operational voltage | Up to 690 V AC |
| Breaking capacity (Icu) at 400 V | 100 kA |
| Main circuit terminals | Screw terminals |
| Integral auxiliary switch | Transverse 1 NO + 1 NC |
| Phase-failure sensitivity | Yes |
| Degree of protection | IP20 |
| Dimensions (H x W x D) | 97 x 45 x 96 mm |
| Net weight | Approx. 0.38 kg |
| Product lifecycle | Phased out; successor 3RV2011-1JA15 |
Where the S0 Frame Sits in the SIRIUS Range
The 3RV1021-1JA15 is neither the smallest nor the largest protector in the family, and substituting the wrong size leaves a motor either under- or over-protected:
| Feature | Size S00 (e.g. 3RV1011-1GA10) | Size S0 (3RV1021-1JA15) | Size S2 (e.g. 3RV2031-4PB10) |
|---|---|---|---|
| Overload setting | 4.5 ... 6.3 A | 7 ... 10 A | 28 ... 36 A |
| Short-circuit release | 82 A | 130 A | 520 A |
| Typical motor power (400 V) | 2.2 kW | 4 kW | 18.5 kW |
| Width | 45 mm | 45 mm | 55 mm |
| Depth | 81 mm | 96 mm | 149 mm |
The S0 frame protects motors in the roughly 4 kW class, stepping up from the 2.2 kW S00 devices while remaining a narrow, DIN-rail unit. Its 130 A magnetic trip and the integral 1 NO + 1 NC auxiliary contact are the features that distinguish it on an existing panel.
Wiring and Setting
The breaker mounts on a 35 mm DIN rail and uses screw terminals on the line and load sides. Set the overload dial to the motor's nameplate full-load current, within the 7 to 10 A band. The transverse auxiliary contact provides a dry signal to the PLC or panel indicator when the device trips, which is useful for remote fault monitoring. Because the unit is phase-failure sensitive, it also trips on single-phasing. Confirm the upstream short-circuit coordination and use conductor sizes and torque values per the published installation data.
Typical Applications
- Three-phase motors around 4 kW at 400 V on conveyors, pumps, and machine tools
- Auxiliary feeders that need a local trip signal via the 1 NO + 1 NC contact
- Replacement of failed 3RV1 S0 protectors on installed SIRIUS panels
- Machine builders and retrofit equipment built around the S0 starter size
You can browse related protection components in our Siemens range and the motor-control collection.
Lifecycle: A Discontinued Part With a Defined Successor
The 3RV1021-1JA15 is a phased-out product. Siemens recommends the SIRIUS 3RV2011-1JA15 as the successor for the same 7 to 10 A rating. Where you are building a new panel, the 3RV2 device is the natural choice. Where you must keep an existing machine on the same footprint and rating, a tested surplus or replacement 3RV1021-1JA15 is often the fastest way back to running. Our Discontinued Products range is built for exactly this kind of sourcing; send us the part number and we will confirm stock and advise on the 3RV2 cross-reference.
Frequently Asked Questions
Is the 3RV1021-1JA15 still in production?
No. Siemens has phased out the 3RV1 series and lists the 3RV2011-1JA15 as the recommended successor for the same 7 to 10 A rating.
What motor does it protect?
Its overload setting covers 7 to 10 A, corresponding to a typical 4 kW three-phase motor at 400 V. Set the dial to the motor's nameplate full-load current.
Does it have auxiliary contacts built in?
Yes. This variant includes a transverse auxiliary switch with one normally-open and one normally-closed contact for remote trip indication.
Can I replace it directly with the 3RV2011-1JA15?
The 3RV2011-1JA15 is the manufacturer-named successor for the same current range, but always confirm the terminal arrangement, auxiliary-contact configuration, and DIN-rail footprint for your specific panel before fitting.
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