I'm going to do some quick and dirty answers to stuff here, move on to the next one, and so forth.
Sorry for this, you just wouldn't imagine the work load that has been tossed onto me
Between two - now possibly three bank branch projects where I need to do field installations [plus anticipate stuff, then note for As-Builts], I will be designing and uploading project notes and images to web pages, for all WAMU projects [this is typical for all of WAMU's contractors]. Each project is to be updated weekly.
Along with this, I am doing customer support / educated walk through on another project - which requires As-Built sets in several "Knowledge Levels" ?? -
And I still have two PCs to finish the reconfigs on [and their owners are calling every minute
Then I have memory upgrades at the Office on three W/S, plus install a few Apps - possible reconfig on one W/S.
Hardly any time to do fun stuff, like this forum!!, so please don't get too discouraged with me over the next 3 weeks if I don't respond to things right away - I'll make time to answer Qs and post images.
Anyhow, the Delta vs Wye connections have certain benifits according to the use of that system.
Deltas can handle Harmonics better [and even eliminate levels].
Wyes are best for multiwire systems, plus used to establish ground points [Zig-Zag transformers].
Capacitor banks are normally connected in Wye.
If the coils in the schematic above were connected in parallel [the split coils, that is], then the L-L and 3 phase voltage would be 120 VAC.
If one phase was grounded [AKA corner grounded], the voltage will still be 120 all around, plus 120 VAC to ground from the other two ungrounded phases.
If we leave the split coils in series as it's shown now - but remove the center tap and reground the system via one phase [once again , make it corner grounded like the 120 VAC setup], then the voltage will be 240 L-L and 3 phase, 240 VAC to ground from the other two ungrounded phases.
Each "Phase coil" in the delta is connected in parallel with the others. This eliminated the need to bring in 6 wires from the transformer, thus making the system 3 phase 6 wire [or 3 phase 7 wire when using a common neutral].
It still works as if there's 6 wires coming from the transformers - currents flow in the same matter.
This would work on preceeding setups - 3 phase 6 wire, 2 phase 4 wire, 1 phase 2 wire [a great way to visualize things].
On Wye systems, same thing goes - in their case, the "Phase Coils" are connected in series additive fashion, so the L-L voltage is 1.732 times the voltage of one single coil. Using the 3 phase 6 wire idea, one can visualize just how L-N load currents work out on the Wye system - because they do just that! [N should be best thought of as Common, so L-C is more correct].
L-C load currents flow from coil, to load in that type of matter.
L-L and 3 phase [L-L-L] loads go between individual phase coils, but L-C loads work from that certain phase coil - hence the fact that it's reather difficult to get the common grounded conductor in 4 wire Wye systems to balance like a 1 phase 3 wire's neutral will.
Got to go to the next one - 6 phase, then I'm off for today.
I'll post some connection schematics for 1 phase transformers, describing the various connections, plus I'll try for a 2 phase Tee schematic and Open Delta schematics - all according to what can be done and when [heard that before??---]