| If you are talking about corner grounded delta: | - it has no "neutral"
But the grounded conductor:
- still gets called neutral, anyway
- can be wired as simply as single phase
- can be confused for single phase by how it is wired
| - as gfretwell wrote it normally powers 3 phase loads; the grounded and | phase conductors are the same size
See #3 above.
| - if A is grounded and only A-B and A-C are supplied, the *grounded* | conductor is sized larger than the phases to match the current it | caries; the wire is not derated | | Wires have their current rating derated for temperature.
| Transformers (like open delta) have their power rating derated for power | factor.
Even for unity power factor?
| You appear to have a strange use for "derated". Your intent would have | been clearer without the table. It is well known how to add 3 phase | currents and voltages.
For any phase angle? It seems some people don't know the phase angles.
The term "derating" seems to be rather misplaced here. When you have a higher current load on certain transformer windings, you call it "derating" to correct it, but when you have a higher current load on a wire you do not?
Go back and look at the table I gave. There are 5 common cases where the current adds differently resulting in different currents on the common conductor. The common phase answers are 180, 120, 90, 60, and 0. I say common even though for 90 degrees, you aren't going to see much in the way of 2-phase/4-phase power anymore (it is common in the sense that the other phase angles probably were never used outside of research labs). And the 0 angle is a case of usage of the same phase as two separate line conductors and a single common conductor (certainly not very neutral). Now as you consider all these phase angles, and the variation in current on the common conductor, you want to vary the terms such as whether neutral is used, or derating is used?
Actually the whole term "derating" is misused, anyway. But that's another whole argument thread ... and unlikely to ever change anything since bad usage, once established, never goes away.