What the code points to
The ABB ACS550-U1-072A-4+B055 is an AC drive in the Motor Drives line (category trail Motors & Motor Controls > Drives > Motor Drives), with the +B055 option suffix applied on top of the base ACS550-U1-072A-4 designation. The order code ACS550-U1-072A-4+B055 and a chassis weight of 31.75 kg are the two items on record; the weight governs panel-mount hardware and lift planning more than any electrical fit decision.
Handling and panel fit
At 31.75 kg the drive is a two-person lift onto a backplate or into a cabinet; the installer should size the mounting surface for that static load before the drive is hoisted into position.
Same-chassis siblings worth knowing
Three ACS550-U1 siblings appear in the evidence set: ACS550-U1-072A-4+B055+L512 at 34.02 kg, ACS550-U1-059A-4+B055 at 36.29 kg, and ACS550-U1-096A-4 at 19.96 kg. The chassis family is shared, so a panel cut for one will accept the others mechanically.