What this reversing starter is — and what it handles
The 3RA2220-4CB27-0AP0: This is a Siemens SIRIUS reversing starter, Size S0, meaning it's a pre-assembled combination of two contactors mechanically and electrically interlocked to reverse a three-phase motor without needing external interlocks or extra panel wiring. The reversing function is built in — the supplied contactor is a 3RT2027-1AP00, and the link module is a 3RA2921-1AA00, so the interlocking and main circuit connections are already taken care of. The maximum AC-3 voltage is 690 V, so it's rated for 400 V class systems with headroom for 480 V or 600 V applications. The horsepower equivalents at 460/480 V are 15 hp, and at 600 V it's also rated 22 A.
Mounting and integration — DIN rail or screw, vertical only
Mounts on a 35 mm DIN rail using an adapter for snap-on mounting, or directly with screws. The mounting position is vertical only — horizontal mounting isn't supported, so plan the panel layout accordingly. Fastening method is on adapter for screw and snap-on mounting on 35 mm DIN rail. Dimensions: 265 mm height, 90 mm width, 120 mm depth. The clearance requirements around the unit: 50 mm upwards, 32 mm forwards, 10 mm downwards, 10 mm at the side, and 0 mm backwards — so it can sit flush against the back panel. The Size S0 footprint matches the circuit-breaker size S0, so the feeder and starter share the same mounting profile. Main current circuit connections use screw-type terminals — standard for panel builders who prefer screw clamps over spring-cage. No special tooling needed beyond a screwdriver.
Environmental limits and temperature compensation
Operating temperature range is -20 to +60 °C, storage and transport range is -50 to +80 °C. The temperature compensation is active over the full operating range, so the overload trip curve stays accurate across the ambient temperature swing in an enclosure. No PROFIsafe or PROFINET IO protocol on this variant — it's a conventional hardwired reversing starter, not a fieldbus-controlled unit. If you need network integration, look at the SIRIUS 3RA6 or 3RA7 series with IO-Link or PROFINET.
The supplied contactor (3RT2027-1AP00) and link module (3RA2921-1AA00) are standard SIRIUS components, so spares and replacements are widely available. The circuit-breaker size S0 matches the starter, simplifying coordination for the feeder protection.