What the line item is
The line item on record carries identification only: part number ACS380-040S-03A3-4, brand abb, series ACS380, unit weight 1.91 kg. No current, voltage, horsepower, frame, IP rating, I/O map, or fieldbus protocol appears in the spec row.
Reading the order code
The order-code grammar reads off the string ACS380-040S-03A3-4: 'ACS380' is the family prefix, '040S' marks frame size and variant, '03A3' is the current-class designator, and '-4' is the voltage-class suffix. No rating value is restated here — it is read off the order-code grammar only. That grammar is what makes the same-frame siblings comparable and the cross-voltage-class ones not — see the next section.
Same-family siblings worth weighing
Among the alternate MPNs surfaced, one carries a decision-relevant delta on voltage class: ACS380-040S-06A9-2 belongs to the -2 voltage-class suffix, while ACS380-040S-03A3-4 carries the -4 voltage-class suffix, so they are not panel-drop-in alternates. ACS380-040S-04A0-4 holds the same -4 voltage-class suffix and so sits in the same input family; the designator difference (04A0 vs 03A3) is a current-class step, not a different product, and would only be a true alternate if the BOM line can accept a higher current rating.