Siemens 3RV2 Series Industrial Component Specifications…

3RV2 Motor Starter Protectors — SIRIUS Circuit Breakers for Motor Protection Up to 100 A

The Siemens 3RV2 series is the motor starter protector (MSP) line within the SIRIUS modular system. Each unit combines a thermal overload relay and a magnetic short-circuit trip in a single compact device — unlike a traditional setup where you wire a separate contactor, overload relay, and fuse. For a 3-phase motor installation, the 3RV2 handles both overload protection (Class 10/10A/20 adjustable trip) and short-circuit interruption in one DIN-rail housing, eliminating the fuse coordination step entirely.

These breakers ship in four frame sizes: S00 (up to 16 A), S0 (up to 32 A), S2 (up to 63 A), and S3 (up to 100 A). Every frame size maintains the same mounting depth and front-panel cutout pattern as its corresponding 3RT2 contactor, so you can snap a 3RV2 breaker and a 3RT2 contactor together with a pre-formed link module to build a motor starter assembly without any wiring between the two devices.

Where You Will Find These

The 3RV2 series dominates European-designed industrial control panels and motor control centers (MCCs). Specific installations include:

Conveyor systems and material handling: Protecting drive motors against jam-induced overload. The phase-loss sensitivity (standard on all sizes, not an add-on) catches a single-phase condition before the motor winding burns.
Pump stations: Submersible and booster pumps where the adjustable thermal release (set with a rotary dial to the motor FLA) avoids nuisance tripping during inrush while still clamping down on sustained overcurrent.
HVAC compressors and fan arrays: The short-circuit breaking capacity of 50–100 kA at 400 V means these can sit directly on a busbar system without upstream current-limiting fuses in many panel designs.
Packaging and bottling machinery: Frequent start/stop cycles where a conventional thermal relay would drift over time. The 3RV2's compensated bimetal strips maintain trip accuracy regardless of ambient temperature swings inside the enclosure.

Versus the older Siemens 3VU series it replaced: the 3RV2 adds an integrated auxiliary contact compartment (no external bracket needed), Class 10/20 selectable trip curve on S0 and above, and a test trip function on the front face that mechanically simulates an overload to verify the control circuit wiring. It also accepts the same SIRIUS accessories (auxiliary/signaling switches, shunt trip, undervoltage release) across all sizes.

Key Selection Parameters

Parameter	S00	S0	S2	S3
Current range	0.11–16 A	0.9–32 A	11–63 A	22–100 A
Breaking capacity Icu @ 400 V	50–100 kA	50–100 kA	50–65 kA	50–65 kA
Trip class	10	10 / 20 selectable	10 / 20 selectable	10 / 20 selectable
Terminal type	Screw or spring-loaded	Screw or spring-loaded	Screw (box terminals)	Screw (box terminals)
Phase-loss protection	Integrated	Integrated	Integrated	Integrated
Width per unit	45 mm	45 mm	55 mm	70 mm

All ratings referenced to IEC/EN 60947-2 and 60947-4-1 (the latter covering the motor starter assembly when paired with a 3RT2 contactor). UL/CSA versions exist for export machinery but carry slightly derated trip ranges — check the specific order code suffix.

How to Choose a Variant

Start with the motor nameplate FLA (full-load amps), not the service factor amps or the upstream feeder rating. The 3RV2's thermal adjustment dial covers a range — e.g., a 2.4–4 A unit can be dialed anywhere in that band. Pick the range where your motor FLA falls between 40% and 90% of the upper end. Setting the dial at the bottom 10% of the range risks nuisance trips; at the extreme upper end, you lose resolution for overload discrimination.

Next, decide on trip class. Class 10 covers most general-purpose motors (trips in 4–10 seconds at 7.2× rated current). Class 20 makes sense for high-inertia loads (centrifuges, large fans, flywheel-driven equipment) where start-up current persists beyond 10 seconds. S0 and larger frames give you the toggle; S00 is Class 10 only.

The terminal choice matters more than it seems. Spring-loaded terminals (cage clamp) on S00/S0 stay torqued over vibration and thermal cycling — worth the small premium on compressor panels. Screw terminals on S2/S3 are box-type with a captive screw design that still holds UL 486 torque tests, but they need a torque screwdriver for compliance documentation.

For coordination with an upstream breaker, use Siemens' SIMARIS design software or the coordination tables in the SIRIUS catalog to confirm selectivity. In most factory-floor panels, a 3RV2 fed from a 3VA molded-case breaker achieves total selectivity up to 50 kA without needing to oversize the upstream device.

Procurement Notes

3RV2 stock status varies sharply by current range. The 0.11–1.6 A and 7–10 A units are high-volume commodity items — normally days away. Ranges between 16 A and 25 A in the S0 frame tend to hit allocation during heavy industrial project cycles (Q2–Q3 in EMEA regions). Frame S3 (63–100 A) units are built to forecast; expect 4–6 weeks if you are not on a standing order. Accessories — particularly the undervoltage release and the door-mounted rotary operator — ship from a separate distribution channel and add a week to assembly. Confirm the accessory kit compatibility table by order code prefix; the S00 auxiliary switch does not fit S0, and the mixing error is common enough to verify before releasing a PO.