Wye Start results in a "Reduced Voltage" at the Stator Windings, and Delta Run results in full Voltage across each Stator Winding.
All the Motor's Winding Leads are brought out from the Motor, and connected to individual Contactors for Wye/Delta setup.
The 3Ø Motor Circuit is connected to the Motor via Mag Starter.
There was a detailed thread regarding this, but I can't remember when or where.
It was here at ECN, but it may have been in this area (General Discussion), or the Theory and Applications area, or even the NEC area!
May need to search them all.
If I find it, I will post a link.
Feel free to ask additional questions if needed.
Scott35
