As with Roy, I didn't wade in as I am not sure there is an answer. There are practical limits as Roy has indicated, but Star-Delta is just one method of several reducing the starting current (along with such things as frequency control starters, auto-transformers, etc.). It is just a matter of deciding what is the most suitable arrangement (with DOL being the ideal as it is the simplest and therefore cheapest).
As with Roy, I didn't wade in as I am not sure there is an answer. There are practical limits as Roy has indicated, but Star-Delta is just one method of several reducing the starting current (along with such things as frequency control starters, auto-transformers, etc.). It is just a matter of deciding what is the most suitable arrangement (with DOL being the ideal as it is the simplest and therefore cheapest).
