ECN Forum Forums Technical Discussion Electrical Theory and Applications Wye schematic - 3rd in the series

Here's one of a 4 wire Wye, using three separate 1 phase transformers - as would be on a pole mounted transformer bank.

Note the complete difference in how the coils are wired here, as to the Delta method??

These coils [split coils] are in Parallel - so each transformer has 120 VAC output. On the Delta, each transformer's split coils are in series, so each transformer has 240 VAC output [the bottom coil is center tapped for the neutral].

Comments??

Scott SET - sorry for the text!!

Scott...
pictures! this is great!

ok, first, how do we describe this? is it a 208/120Y , 480/277Y ? do we only describe the secondary ?

Steve,

For ease of discussion [not sure what that means?? - joke], let's only view the secondary of this transformer.
FYI: The primary could be either Delta or Wye, it makes no difference to the secondary.

This monster is using the before mentioned single phase split coil transformers [covered in the "Delta schematic" thread].
It's using 3 separate transformers - one for each "phase".

This schematic would be how a 208Y/120 VAC 3 phase 4 wire Wye is connected - using split coil transformers having 120/240 VAC outputs.
For a 480Y/277 VAC 3 phase 4 wire Wye, the transformers might be split coil [if there's any which have 480/277 outputs], but most likely the transformers will have a single coil, which is wound for 277 VAC output.

Back to the above schematic:
The split coil secondaries on each transformer are connected in parallel, so the output voltage from each transformer coil is 120 VAC [much different than the delta one, isn't it??].
The X2/X4 ends of each transformer connect to the common jumper, whereas the X1/X3 ends run straight out - forming the output for that phase. Relative polarity in this case is setup so that each coil is in a series additive connection through the "jumper wire" and their respective X2/X4 outputs.
BTW: X1/X3 get connected together - so do X2/X4.

The "jumper wire" on this arrangement is tapped into and thus becomes the common neutral. If this was to be a 3 wire system only, no tap to the jumper is made. Tapping the jumper makes it a 4 wire [AKA multiwire] system.

Reviewing the schematic, you will see that each transformer coil's output is 120 VAC - so if you take your Wiggy and measure voltage from any one of the output phase ends to the common jumper wire, you will get a reading of 120 VAC.
Connecting the Wiggy across any two phase outputs will give a reading of 208 VAC [120 VAC x 1.732].
If you have an intellegent Octopus, it could simultainiously connect Wiggys across all of the phases, showing that theres also 208 VAC potential between L-L-L [3 phase].
If you own such Octopus, please let me know where to get one!! Needed ASAP!!

Scott SET - putting the "Wye" in "Why the heck won't he just make some sense"

I forgot to mention that both schematics shown are the same - I just included them both to demonstrate how their symbols are configured.

In other words, the uppermost schematic is drawn out in the familiar Wye fashion - it's drawn with one winding at 0 degrees on the Y axis, then the other two windings are attached at 120 degree intervals from the Y axis [this is to reflect electrical degrees - somewhat..].

The drawing below it shows how everything relates to the symbolic schematic - it shows how everything gets connected exactly the same as the Wye schematic, but looks more simpler due to being an easier to read 1 line schematic.

I was hoping these methods will help persons visualise the symbolic connection easier [try to make it easier to visualise how they end up connected], which is the reason for posting both types of schematic drawings.

Scott SET - clogging your head with endless non important trivia

P.S. - had a typo to edit out!!

[This message has been edited by Scott35 (edited 05-11-2001).]

OK, the editing has been successful!! Hur-rayeeee!!!!! Queetohs yang fong [I was watching Get Smart and someone just said that - sounded good, so I included it here].

On the subject of Get Smart, why the heck won't they just trash that Cone-Of-Silence??
That sucker is always broken!! Way too much overhead on that piece of equipment.

Oh, the schematic in this thread should make more sence now - even if the joker that posted it's message context doesn't make any [this is applied to SET!!]

Any comments on these topics [schematic, or Control's reluctance in getting rid of malfunctioning security equipment]??

Scott SET

if the cone of silence really worked, i'd get one for the kids, but i suspect Kaos had some input in it's design...

ok, so why parrallel coils?, why not series coils???

I too suspect that Kaos was involved with some level of design here, as it's operation is inverted [can't hear conversation inside but if your outside it's clear as a bell].

Plans most likely have Siegfried's PE stamp on them

Having the split coils connected in parallel on this arrangement produces 120 VAC in that coil. Connecting all three individual transformers in a Wye configuration where the voltage of each transformer is 120 VAC will produce 208 VAC L-L / L-L-L, or 120 VAC to the common - this is the common method of creating a 208Y/120 VAC 3 phase 4 wire Wye system when using 3 common type 1 phase 120/240 VAC split coil transformers [Utility Companies' pole mounted xformer banks].

If the split coils were connected in series additive, the voltage of each transformer will be 240 VAC.
Now if we connect the 3 individual transformers in a Wye configuration where the voltage of each transformer is 240 VAC, the L-L / L-L-L voltage will now be 416 VAC, and of course the voltage from any one of the three transformers to the common will be 240 VAC.
This would be a 416Y/240 VAC 3 phase 4 wire Wye system.
If the common is not used, then the system would just be a 416VAC 3 phase 3 wire Wye.

BTW: Can you see how the pictorial "Y" schematic is made up of 3 individual transformers?? That's why I wanted to have the pictorial schematic drawn above the 1 line schematic - so there's a visual relationship to use.

Scott SET

***BUMP***

Scott35