Resistance of the star (wye) connection

[jearls74]

Does the resistances of each phase in a 3 phase generator add together in the Star (wye)?

I read on a windmill site that the Delta connection is typically one third the resistance of the Star. So if i had 3 phases that were .5 ohms each in Delta configuration, would the resistance be 1.5 ohms in Star?

 

[LotusEffect]

Do you mean the internal resistance of the generator? If so I think you should add those resistances with the ones of the load in its wye config.

For your second question: it's the opposite. If you have to convert a three phase wye load to a delta load, the new impedances will be three times the wye impedances. That is, if the load is balanced. If not you should apply the equations listed there http://en.wikipedia.org/wiki/Y-Δ_transform.

edit : If you meant that you would keep the same elements and connect them in star rather than delta, then yeah, as seen from the source, the impedance of the delta config would appear lower. What is written in the paragraph above is about what should be done to know the equivalent circuit as seen from a source. That is, three 6 ohm resistors connected in wye is the same as three 18 ohm resistors connected in delta : the line currents will be the same.

However if you keep your 6 ohm resistors that were connected in wye and then connect them in delta, the source will see three 2 ohm resistors connected in wye (or three 6 ohm resistors connected in delta!)