ECN Forum Forums Technical Discussion Electrical Theory and Applications Transformer Discussion #3

T3b = 3 Ph. Delta pri. to 6 Phase secondary [Delta / Wye] - Rectifier
Transformer.
X1, X2, X3 = Delta sec. - Y1, Y2, Y3 = Wye sec.


Here's another Rectifier Transformer, but this one has a 6 phase output, instead of a 9 phase output. Primary is 3 phase Delta.

Secondary Terminations:

X1, X2, X3 = Delta 3 phase 3 wire,

Y1, Y2, Y3 = Wye 3 phase 3 wire.

These coils have epoxy resin potting, which is why they have the black coating on them.

FYI: Note the "Common" conductor at the bottom of the coils, which connects the "X2" ends of the coils for the Wye Secondaries in series additive connection.
That wire at the bottom of the coils is the one which is connected to the Grounded Conductor [AKA "Neutral"] on 4 wire Wye systems]. That's where the common grounded conductor makes a complete circuit to the 3 phase coils.
As you can see, it is nothing at all like the Grounded Neutral of a 1 phase 3 wire system - it's not a center tap on a winding, but is a common connection to all coils.

Any comments??


Scott SET

[This message has been edited by Scott35 (edited 04-18-2001).]

Scott,
is the secondary either wye or delta, or are they dual usage ( at the same time)?

is that noodle common to prim & sec coils?


p.s.- I haven't got ANYTHING like this in my humble little library !

Steve [Sparky],

This core has two individual and completely separately wound Secondary coils.
One is connected in Delta [the 3 coils are connected in a Parallel fashion] - these output terminals are:
X1 [Phase A],
X2 [Phase B] and
X3 [Phase C].
The other is connected in Wye [the 3 coils are connected in a Series Additive fashion] - these output terminals are:
Y1 [Phase A],
Y2 [Phase B] and
Y3 [Phase C].

Primary connections are on the other side of this core - right behind this term. block.

The Primary is Isolated from each Secondary, plus each Secondary is Isolated from each other - only wound on the common "Core".

Primary is Delta connection [Parallel Coil Connection Fashion] with terminations being:
H1 [Phase A input],
H2 [Phase B input] and
H3 [Phase C input].

Both Secondaries can be driving loads at the same time. This Transformer is designed to run a 6 phase rectifier [actually a dual 3 phase section rectifier], but it could just as easily be driving 208 volt 3 phase 3 wire and 240 volt 3 phase 3 wire loads simultanously.

I'll add some more info later with schematics.


Scott SET

P.S. the edit is to a spelling error I found after posting the message - instead of the word "Wound" to a common core, I had "would" - that "Would" have benn quite the Corn-Fuser
Hope there's no more!!

SET

[This message has been edited by Scott35 (edited 04-22-2001).]