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#129783 08/19/05 02:39 PM
Joined: Dec 2004
Posts: 1,064
D
Member
480x208/120Y Transformer

How can the primary be close to being balanced, but the secondarys be way out of whack?

I measured a different trans today and found the readings, primary balanced close, but not secondarys of the wye.


Shouldn't the primary windings be unbalanced just as much as the secondarys?


Anyone got an explanation?


Dnk.....

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#129784 08/19/05 09:34 PM
Joined: Mar 2002
Posts: 582
R
Ron Offline
Member
Since there is no bolted primary to secondary phase connections, the balance on the primary may not match the secondary exactly, but they should be close considering the turns ratio. 2.3x for your transformer


Ron
#129785 08/21/05 03:15 PM
Joined: Jun 2004
Posts: 1,273
T
Member
480x208/120 XFMRS is 4:1 not 2.3

The 480 Volt delta windings are wrapped around each 120 Volt wye leg.

4/1.73205 = 2.3 The implied ratio for 208 Volts.


Tesla
#129786 08/25/05 08:24 PM
Joined: Feb 2005
Posts: 693
L
Member
Dnk, you've discovered why high-voltage transmission lines are basically floating delta systems - I've heard an engineer call it "self-balancing".


Larry Fine
Fine Electric Co.
fineelectricco.com
#129787 08/26/05 05:57 AM
Joined: Dec 2004
Posts: 1,064
D
Member
Larry, can you elaborate on the "floating Delta"?

I assume by your post, the readings I am getting may be normal then?

Dnk.....


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