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We are talking about a three-phase supply here, with each phase named red, yellow or blue, and on a vector diagram they are 120 degrees apart. Delta winding means that each of the three phases is connected to its two neighbours and when drawn this looks like a triangle or the Greek symol Delta. This is used for the primary winding of your transformer. Star winding is the alternative, and in this case each phase is connected to a common central point which because it is the average of all three phases at any instant is at zero volts. This is used for the secondary winding of your transformer. Thus a 415 volt three-phase supply (i.e. 415 volts between any two phases) to your building can be split up into three separate single phase supplies of 230 volts when measured between the phase and the central point, one end being the "Live" and the other (zero volts) being the "Neutral". This means that your building can have three separate 230 volt distribution panels working off one 415 volt supply from the local substation.

2007-03-19 10:17:28 · answer #1 · answered by Andrew M 1 · 1 1

Δ-Y transformer
From Wikipedia, the free encyclopedia


A Δ-Y transformer is the North American term for an electrical device that converts three-phase electric power without a neutral wire into 3-phase power with a neutral wire. It is generally built from 3 independent transformers.

They are known as Delta-Star systems in Europe, where an example would be a distribution transformer with a delta primary, running on three 11KV phases with no neutral or earth required, and a star (or wye) secondary providing three 240v phases and an earthed neutral point.

Δ-Y transformers should not be confused with the Y-Δ transform, which is a mathematical transformation used in circuit analysis.

2007-03-19 17:20:08 · answer #2 · answered by Rod Mac 5 · 0 0

Wow some `great answers here`..... Very basically a Y configuration three phase supply has a neutral, connected to the star point, i.e. the centre of the Y. The Y configuration allows an unbalanced load - that's why domestic supplies are always in the Y config, e.g. (houses) Street A L1/N, Street B L2/N and Street C L3/N - In the UK each phase to neutral is ~240v.
Delta does not have a neutral and therefore must be connected to a balanced load, e.g. A motor or Oven (the load on each phase must be balanced) - again in the UK between phases = ~415v.

2007-03-20 07:32:45 · answer #3 · answered by Anonymous · 0 0

Large buildings require huge power loads of electricity.
Depending on the primary power use, electric circuits can be connected 2 ways. Both 3 phase connections have advantages and disadvantages to power the load. In buildings with large motor loads, most electric supply connections are delta. This means that the individual windings of the 3 phase transformer that supplies electric to the building is connected in series with each other. In buildings using mostly lighting, the transformer windings are connected wye. This means the individual windings are connected in parallel. The advantage of delta compared to wye in large power loads is that the current flow is in series and this makes the generator or motors run smoother. The advantage of wye connected buildings is that all 3 individual power legs can supply equal voltage and divide the electric light load to all 3 legs. Hope this helps.

2007-03-19 17:14:34 · answer #4 · answered by Anonymous · 0 2

am guessing that the seperate spurs act as individual ring mains and the transformer bears the brunt of current loading.

2007-03-19 16:44:37 · answer #5 · answered by Icarus 6 · 0 1

so it behaves like a ring main... or it will overload

2007-03-19 16:40:16 · answer #6 · answered by Anonymous · 0 2

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