The Schneider VW3A58604 is an Altivar supply separator — ALIMENT.CONTR.SEPAR.T4/T5 — designed to isolate the control supply from the power section on T4 and T5 frame drives.
Schneider lists this part as obsolete. The lifecycle stage is marked mature, which in this context means the part has reached end-of-production and is no longer manufactured.