meirs Jul 5, 2010:

star point grounded First, its most probably about a 3-phase system (otherwise there is no start point). The start point is where all the 3 phases are connected. Original text should mention like this "an isolation transformer with the secondary star point grounded". Secondary is implied but need be specified iMHO. Separation is from German *Trenntransformer* / *Trennwandler* - English is isolation. Grounded at the end because the star point is a part of the transformer, and the grounding is done externally (when it is connected to the other parts of the whole installation.