The 4 kW G120X carrying the DC-link terminals through the alternative ordering designation: the FSB frame at 230 V, the 1 in the order code for the du/dt filter connection, the F at the end for the second catalog channel. 18.1 A nominal, 23.7 A max, unfiltered, IP20.

When does the F designation matter to procurement?

When the buying system already runs on F codes. A site that has ordered its drives through the F line keeps quoting it for every new station - the designation appears in the master data, the approvals and the internal parts list, and switching one drive to the P line for the same hardware breaks that chain for no technical gain. The F is not a different drive: the 1UP0 is the same FSB frame, the same 18.1 A nominal, the same DC-link terminals. What the engineering table specifies for the P twin applies to this drive as it stands; the channel is the only thing that moves.

What do the DC terminals protect on a 4 kW line?

The motor, from the drive itself. The switching edges of the converter travel down the cable, and a long cable reflects them back into voltage spikes at the motor terminals - insulation aging that a panel-mounted drive never shows on its own terminals. The fix sits upstream of the cable: the du/dt filter mounts between drive and motor run, and it needs the DC-link connection that only the 1-prefix 4 kW drives carry - on the 0-prefix there is nowhere to land it. The protection is purchased at ordering time, not later: a station built on the 0-prefix that needs the filter afterwards changes the drive as well as the wiring.