Contactor connection question

[CDG16]

Assume a normal Star-Delta Automatic starter. I have seen in many text books that the connections to the Delta contactor is made from the supply side of the Main contactor. This means that these terminals on the Delta contactor are always live. Why not take these wires from the bottom of the Main contactor? This ensure less live wires in the circuit when not in operation. The only reason I can see for this, is that you will be able to use a smaller rated Main contactor. I.e. when running in Delta, not all current is passing through the Main contacts. Is this assumption correct or are there other benefits in the text book connections?

Your answers are much appreciated.

 

[Walden]

I have seen a star/delta starter with no main contactor at all! Three of the six motor winding terminals were permanently connected to the three phase incoming supply through fuses. A star and a delta contactor only were used to start the motor. The thermal overload relay was fitted to the delta contactor.