Panel fit for an S2 direct starter
The 3RA2150-4KA38-0AP0 is a direct on-line starter — across-the-line motor starting with no soft-start or VFD. It ships as a pre-assembled unit: the 3RT2038-1AP00 contactor, the thermal bimetallic overload relay, and the 3RA2931-1AA00 link module that wires the two together. Mounting uses screw fixing or snap-on to two parallel 35 mm DIN rails — the S2 frame needs the dual-rail stability because the assembly is 274 mm tall and 150 mm deep. Plan for 55 mm of DIN-rail width per starter; the depth clearance behind the panel door must accommodate the 150 mm projection plus wiring space. Ambient temperature compensation is active across the -20 to +60 °C operating range, but the bimetallic element still tracks enclosure temperature, so avoid mounting directly above heat sources.
AC-3 and AC-3e duty — what 73 A means for motor sizing
Rated 73 A at AC-3 400 V and 73 A at AC-3e 400 V — the AC-3 figure covers standard squirrel-cage motor starting (6–8× inrush, switching off at running current), while the AC-3e rating adds margin for higher switching frequencies typical in cyclic applications. Both ratings are identical here, so the contactor is not derated for the enhanced duty class. At 480 V the rating drops to 65 A, and at 600 V to 62 A — the current ceiling follows the voltage rise because the contactor's arc extinction capability is voltage-limited. For a 37 kW motor at 400 V (the listed power rating), the 73 A AC-3 figure gives headroom above the motor FLA of roughly 65–68 A for a standard efficiency motor. The maximum rated operational voltage is 690 V AC-3, so this starter can be used on 400/480/600 V systems without exceeding the contactor's voltage withstand. The screw-type main circuit terminals accept standard lug sizes for the S2 frame current range.
Lifecycle and sourcing — active line, no obsolescence watch
The substance prohibitance date of 03/01/2017 confirms RoHS compliance per EU Directive 2011/65/EU. No stock-holding claim; each RFQ is priced against the day's market.