Here is a breakdown of the product code ACS550-01-087A-4:

ACS550: This indicates the series or model of the ABB Inverter.

01: The first two digits after the series code represent the design version of the drive.

087: The next three digits represent the maximum continuous output current rating of the drive, measured in amperes.

A: The letter following the current rating represents the enclosure type. In this case, "A" typically indicates a standard enclosure.

4: The last digit represents the input voltage range and the power supply characteristics. It may vary based on the region or specific requirements.