Coordination tables for building a Siemens SIRIUS motor starter from a 3RV2 motor protection circuit breaker and a 3RT2 contactor. Covers frame sizes S00, S0, S2, S3, S6, S10 and S12, IEC 60947-4-1 type-1 and type-2 coordination categories, direct-online (DOL) and star-delta (Y-Δ) starter architectures, and typical current settings for AC-3 motor duty. Includes decoding of the 3RV2 and 3RT2 catalog references.
A Siemens SIRIUS motor starter comprises three protective and switching devices arranged on a single modular assembly. Reading top-to-bottom on the panel: the 3RV2 motor protection circuit breaker (MPCB) provides thermal overload and short-circuit magnetic protection; the 3RT2 contactor makes and breaks the motor current on command; and an optional 3RA2 wiring kit connects the two while allowing direct busbar feed for parallel starters. This document covers the pairing rules that determine which 3RV2 pairs with which 3RT2 for a given motor rating.
A Siemens 3RV2 MPCB is coded 3RV2 XX X X XX where each position identifies a selection parameter.
| Position | Encodes | Values |
|---|---|---|
| 3RV2 | Family | Fixed: SIRIUS 3RV2 MPCB |
| chars 5-6 | Frame size | 01 = S00 (0.16 – 16 A); 11 = S00 (0.11 – 16 A screw); 21 = S0 (0.11 – 32 A); 31 = S2 (0.11 – 40 A); 41 = S3 (14 – 100 A) |
| char 7 | Release class | 1 = motor protection with instantaneous magnetic; 4 = motor protection with 13× magnetic (soft starters); 7 = short-circuit only (starter combination) |
| char 8 | Terminal type | A = screw; B = spring; K = ring lug |
| chars 9-10 | Current setting range | Coded lower bound (10 = 6.3 – 10 A; 15 = 10 – 16 A; 20 = 14 – 20 A; 25 = 20 – 25 A; 32 = 22 – 32 A; 40 = 34 – 40 A; …) |
Frame S00, motor protection release (instantaneous 13× magnetic + thermal overload), screw terminals, setting range 0.11 – 0.16 A. Suitable for very small motors such as 24 V DC dampers or single-phase blowers.
The paired 3RT2 contactor is coded 3RT2 XX X X XXX. Chars 5-6 give the frame size (matching the MPCB) and chars 7-10 encode the coil voltage and auxiliary contact arrangement.
| Frame | 3RT2 range | AC-3 rating at 400 V | Motor duty |
|---|---|---|---|
| S00 | 3RT2015 – 3RT2018 | 7 – 12 A | 3 – 5.5 kW |
| S0 | 3RT2023 – 3RT2028 | 17 – 38 A | 7.5 – 18.5 kW |
| S2 | 3RT2035 – 3RT2038 | 40 – 50 A | 18.5 – 22 kW |
| S3 | 3RT2045 – 3RT2047 | 65 – 80 A | 30 – 45 kW |
| S6 | 3RT1054 – 3RT1056 | 115 – 185 A | 55 – 90 kW |
| S10 | 3RT1064 – 3RT1066 | 225 – 300 A | 110 – 160 kW |
| S12 | 3RT1075 – 3RT1076 | 400 – 500 A | 200 – 250 kW |
To pair an MPCB with a contactor, choose the MPCB whose setting range brackets the motor's full-load current (FLC), and choose the contactor whose AC-3 rating at the system voltage is at least equal to that FLC. Both devices must share a frame size to fit the 3RA2 wiring kit that connects them.
| Motor FLC (400 V AC-3) | MPCB (setting range) | Contactor | Frame |
|---|---|---|---|
| 2.4 A (0.75 kW) | 3RV2011-1CA10 (1.8 – 2.5 A) | 3RT2015-1AB01 | S00 |
| 4.0 A (1.5 kW) | 3RV2011-1EA10 (2.8 – 4.0 A) | 3RT2015-1AB01 | S00 |
| 7.0 A (3.0 kW) | 3RV2011-1HA10 (5.5 – 8.0 A) | 3RT2016-1AB01 | S00 |
| 12.0 A (5.5 kW) | 3RV2011-1KA10 (9.0 – 12.5 A) | 3RT2018-1AB01 | S00 |
| 18.0 A (7.5 kW) | 3RV2021-4CA10 (16 – 22 A) | 3RT2025-1AB00 | S0 |
| 25.0 A (11 kW) | 3RV2021-4EA10 (22 – 32 A) | 3RT2026-1AB00 | S0 |
| 40.0 A (18.5 kW) | 3RV2031-4WA10 (35 – 45 A) | 3RT2035-1AB00 | S2 |
IEC 60947-4-1 defines two coordination categories following a short-circuit. Type-1: no danger to the operator, but the starter may not be reusable. Type-2: no danger, and no damage to the contactor or overload other than light welding of the contactor tips that can be broken free with a screwdriver. Type-2 is the norm on cargo pumps, thruster motors and any motor whose unplanned outage stops the vessel. Siemens publishes type-2 coordination tables in the SIRIUS Innovations manual; the pairings above are all type-2 up to 50 kA prospective short-circuit at 400 V.