SIRIUS 3RT2 Contactor

Siemens SIRIUS 3RT2 — Compact Contactors for Space-Optimized Control Panels

The SIRIUS 3RT2 series is Siemens' compact contactor line optimized for space-constrained control panels, covering motor switching from 7A to 38A (AC-3, 400V), with motor power ratings from 3kW to 18.5kW. With over 3,100 variants, the 3RT2 delivers the same switching performance as the 3RT1 in a reduced footprint.

Why Choose 3RT2 Over 3RT1?

A 3RT2 contactor for 9A occupies roughly 15% less panel space than the equivalent 3RT1. The savings multiply in large Motor Control Centers (MCCs) where DIN rail real estate is the binding constraint.

Key advantages of the 3RT2 series:

• Reduced Width: S00 frame (7A-12A) at 45mm, S0 frame (16A-38A) at 55mm.
• Integrated Surge Suppression: Built-in varistor or RC suppression circuits on selected models eliminate external suppressor modules.
• Plug-in Control Wiring: Removable control terminal blocks allow pre-wiring of control circuits before contactor installation, speeding up panel assembly.
• Solid-State Compatible: All 3RT2 contactors are rated for use with solid-state PLC outputs (24V DC, 0.5A minimum).
• Spring-Type and Screw-Type Terminals: Available in both terminal styles without changing the contactor width.

Application Scope

• Standard Motor Starters: Combined with SIRIUS 3RU thermal or 3RB electronic overload relays up to 18.5kW.
• Building Automation: HVAC fan and pump control, lighting contactors, blind/shutter motor control.
• Machine Tool Auxiliary Circuits: Hydraulic pump motors, coolant pumps, chip conveyor motors.
• Renewable Energy: Auxiliary circuit switching in solar inverters and wind turbine control.

Selection Guide

For applications above 38A, use the SIRIUS 3RT1 series (extends to 500A). For DC switching, refer to SIRIUS 3TC series.