Why some motors are connected in delta at first then in star?

Please refer to the link mention below. This question has been answered by others previously.

http://www.bayt.com/en/specialties/q/2465/why-is-star-delta-starter-preferred-with-an-induction-motor/

Actually, the connection mentioned by you is in reverse. First, it is connected in star, then it switches to delta.

for me .. am not facing this type of connection .. but if there is some you can take a look at the the delta and star connection characteristics  , ex if we take delta what are the output chtics for these connection:

V phase equal to V line ... high volt come out with high torque  T =K*Vsqu ... high starting torq low starting current .. first  we should look at load characteristics to select the optimal starting type