What the code buys you
The ABB ACS380-040S-01A8-4 is a member of the ACS380 series of motor drives, listed at 1.36 kgs. The -4 suffix places it in the 400V supply class, and the frame form factor carries the standard ACS380 mounting footprint for that family. Catalog path is Motors & Motor Controls, sub-class Motor Drives, ACS380 series, general-purpose inverter slot, not a dedicated motion or servo position.
Cross-shop against ACS380 siblings — what you actually gain
The closest same-series reference is ACS380-040S-06A9-2, which sits in the 200V supply class rather than the 400V class of the ACS380-040S-01A8-4 — different mains, different DC-bus, not a panel drop-in. ACS380-040S-04A0-4 shares the 400V supply class but steps up in current rating; it is a frame and a half above the ACS380-040S-01A8-4 and ships at 1.81 kgs, so it would not physically swap into the same panel footprint. ACS380-040C-05A6-4+K475 is a different catalog tier (the -040C variant with an option code) and comes in lighter at 1.13 kgs; it is a parallel model in the same voltage class but not a one-for-one replacement for the -01A8-4.
Sourcing posture
Confirm the 400V supply class against the panel mains and the motor nameplate full-load current before signing off — the -4 suffix is the only voltage discriminator visible in the codespec, and swapping in a -2 sibling (200V class) silently halves the DC-bus and will not start the same motor.