What it is and why the suffix matters
The ABB ACS550-01-015A-4+B055 is an ACS550-01 series wall-mount AC drive carrying the +B055 option suffix; ordering that full string is what locks in the configured variant on the BOM line, not just the base drive code. It sits in the ACS550-01 mechanical frame at a listed shipping/handling weight of 10.34 kg — meaning a single installer can lift and mount it without rigging, which is the practical reason this frame keeps showing up in retrofit panels where the old drive has to come out and the new one goes in on the same day.
Class context — ACS550 family position
Within the ABB drive catalogue, the ACS550-01 is the wall-mount industrial AC drive line used for fan, pump and general-purpose constant- or variable-torque motor control; the +B055 suffix is a configured option on top of the base frame rather than a separate product class.
Sourcing posture
With no production-status entry on file, this part is sourced to order against an RFQ: the configured code is what the BOM line carries, and supply is qualified through the multi-channel industrial-automation reach rather than assumed off-the-shelf. The procurement decision the buyer came for is whether ACS550-01-015A-4+B055 as specified is the line item that ships — RFQ in, quote against the full configured string including the +B055 suffix, not against the base drive code.