The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Search Function
by Webmaster
01/18/17 11:13 PM
Forum Software Upgrade coming soon...
by Webmaster
01/18/17 09:17 PM
ESA Arc flash course
by frank
01/18/17 04:25 PM
Re: Fabricating Guards out of Lexan?
by frank
01/17/17 04:11 PM
Would ELV branch circuits be a good idea?
by gfretwell
01/17/17 01:26 PM
New in the Gallery:
Desk-mounted "power-board"
Top Posters (30 Days)
Webmaster 29
HotLine1 21
Ruben Rocha 16
Trumpy 12
ghost307 12
Who's Online
1 registered (Webmaster), 0 Guests and 183 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#129783 - 08/19/05 12:39 PM Balancing loads
Dnkldorf Offline
Member

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?


Dnk.....

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

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
_________________________
Ron

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

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.
_________________________
Tesla

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

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.
fineelectricco.com

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

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?

Dnk.....

Top


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals