Rating the buyer actually decides on
The ACS550-01-023A-4: On the spec sheet, the headline number a buyer specifies into the BOM is the 23 A current class carried in the order code, paired with the 9.00 kg unit mass. The mass is small enough to handle solo off the pallet, but on a rolling-mill MCC mounted above eye level that 9.00 kg still wants the back-panel braced — not a sheet-metal-only mount when the cabinet sits next to a furnace. Plan the lifting plan around one installer with a panel-side hoist rather than a two-man catch.
How it sits against adjacent ABB drives
The HVAC/ACH variant ACH550-UH-023A-4 carries the same 23 A current class as the ACS550-01-023A-4 but weighs in at 11.34 kg, with a different firmware feature set aimed at building-services fans. On a rolling-mill line the ACH firmware is the wrong tool — its pump/fan macros do not include the tension-control and ramp-hold logic the strip needs at the coiler. Specify the ACS550-01 for any line that has to hold strip tension under a reel.
Mill-floor integration checklist
Mount the drive in a cabinet section that breathes — the ACS550 line relies on forced-air cooling and the heat sink fins will choke if they're boxed in against a cable duct on the furnace side. Keep the input line reactor or, where the spec calls for it, the dU/dt filter as close to the drive terminals as the gland plate allows; long pigtails on a 23 A drive let the carrier frequency noise back-couple into the analog reference for the tension load cell. Grounding needs to be star-pointed at the cabinet floor, not daisy-chained across drives — adjacent megawatt inverters on the same floor will inject common-mode noise that the 9.00 kg ACS550-01-023A-4 can otherwise pass straight into the encoder return on a coiler mandrel.