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!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
Son of Sparky
by gfretwell
10/16/16 07:53 PM
230 or 345 kV transmission lines?
by annemarie1
10/12/16 01:23 PM
Is this a fix or just a bandaid?
by gfretwell
10/10/16 06:49 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 11
renosteinke 6
ghost307 5
HotLine1 5
Potseal 4
Who's Online
0 registered (), 297 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#17519 - 11/27/02 06:03 AM Delta Transformer Configurations
dturner Offline

Registered: 02/20/01
Posts: 16
Loc: Harrisburg PA USA
I need a quick refresher. When hooking up transformers in a DELTA configuration what are the pro's and con's (other than cost) of using "Closed Delta" or "Open Delta".

Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#17520 - 11/27/02 02:15 PM Re: Delta Transformer Configurations
electric-ed Offline

Registered: 07/08/02
Posts: 184
Loc: Canada
If one transformer of a delta-delta connected bank becomes defective, it can be disconnected, and the system will continue to function as an open-delta, but can only deliver 58% of its closed-delta rating.

In my area they were used when transformer insulation wasn't as good as it is today.

They used to install two transformers, connected open-delta, and add the third, (in other words "close the delta") at some point in the future when the load increased.



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