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#129783 - 08/19/05 12:39 PM Balancing loads
Dnkldorf Offline

Registered: 12/12/04
Posts: 1091
Loc: nowhere usa
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?


#129784 - 08/19/05 07:34 PM Re: Balancing loads
Ron Offline

Registered: 03/13/02
Posts: 577
Loc: White Plains, NY
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

#129785 - 08/21/05 01:15 PM Re: Balancing loads
Tesla Offline

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
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.

#129786 - 08/25/05 06:24 PM Re: Balancing loads
Larry Fine Offline

Registered: 02/18/05
Posts: 684
Loc: Richmond, VA
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.

#129787 - 08/26/05 03:57 AM Re: Balancing loads
Dnkldorf Offline

Registered: 12/12/04
Posts: 1091
Loc: nowhere usa
Larry, can you elaborate on the "floating Delta"?

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



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