single phase 230v three phase voltage 415volt why we aren't
used line voltage 690v?
Answer Posted / paul jeffery
Some countries (E,G. Sweden) and processes (E.G. Paper pulp) do use 690 V line to line systems (400 V line to neutral)and transform to 690 v from 11 kv. Wind farms often generate at 690 v and step up to 11 kv to synchronise with the grid. 690 v reduces cable sizes and cost vs 400-440 v systems and enables much larger motors to be DOL started - up to 600 kw plus compared to 200 kw plus for 400 v units. A 400 delta connected motor will operate at 690 v when star connected. These are the basics but 690 v has many advantages over 400 v.
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