Previous in Forum: Forward Converters   Next in Forum: Terjem
Close
Close
Close
8 comments
Rate Comments: Nested
Participant

Join Date: Aug 2013
Posts: 1

Three Phase Toroidal Transformer Design

10/16/2013 8:03 AM

We are one of the manufacturer of toroidal power transformer(230V/single phage/50Hz),toroidal power inductors, common mode chokes etc.

I need to discuss one point, is it possible to design three transformer using toroidal core.

I was searched out in websites, but it difficult to found answer for this question.

Please explain in details.

P.S.Kumar

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#1

Re: Three phase Toroidal transformer Design

10/16/2013 8:12 AM

Maybe three separate toroids, yes.

Or one could use one transformer for each phase, perhaps?

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
United States - Member - New Member

Join Date: Mar 2010
Location: In the pool because it is too hot.
Posts: 3054
Good Answers: 141
#2

Re: Three phase Toroidal transformer Design

10/16/2013 8:45 AM

You might examine, what is left of flux in the core when all phases have a similar (same value) load and same cos. phi. Vectors can show this. You could find some similarities with the current through a zero (nul- neutral) in a Star (Wye) 3 phase net. Maybe, perhaps, probably when the balance is gone? Cores of 3 phase transformers have separate magnetic lanes. They can mould multiphase for ferrite too, but winding your coils will be a much bigger challenge as with single toroids.

__________________
Plenty of room here
Register to Reply
Guru

Join Date: Apr 2011
Posts: 8006
Good Answers: 286
#3

Re: Three Phase Toroidal Transformer Design

10/16/2013 12:44 PM

Probably not as a standard torroid... at least not while acceptably small (physically and financially).

.

Perhaps if your shape was something like the following but with a connection each at each place the core crosses over itself....

.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#4

Re: Three Phase Toroidal Transformer Design

10/16/2013 1:51 PM

I do not believe that this is possible with a single toroid. There is only one magnetic field path in a toroid. I believe that a three phase transformer requires three magnetic field paths. Adding one more hole to the topology provides three manifold paths that will allow for three magnetic field paths.

If somebody knows otherwise, I'd love to hear how this can be done.

__________________
"Don't disturb my circles." translation of Archimedes last words
Register to Reply
Guru

Join Date: Apr 2011
Posts: 8006
Good Answers: 286
#5
In reply to #4

Re: Three Phase Toroidal Transformer Design

10/16/2013 2:35 PM

It can probably be accomplished with an over-sized toroid with shorted coils wound between each phase, a-la shaded pole.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply
Guru

Join Date: Oct 2006
Location: Surrey BC Canada
Posts: 1571
Good Answers: 42
#7
In reply to #4

Re: Three Phase Toroidal Transformer Design

10/17/2013 2:26 AM

How about a Scot T transformer - 2cores.

Register to Reply
Guru
New Zealand - Member - Kiwi Popular Science - Weaponology - New Member Engineering Fields - Power Engineering - New Member Engineering Fields - Electrical Engineering - New Member

Join Date: Sep 2006
Location: Auckland, New Zealand
Posts: 8777
Good Answers: 376
#6

Re: Three Phase Toroidal Transformer Design

10/16/2013 2:56 PM

The common practice is three separate toroidal cores. This is done both for ease of manufacture and cost as you use the same single phase toroidal transformer design and parts, just three of them.

I am not aware of any three phase toroidal transformers using a single toroid. Doesn't mean it might not be possible, but I cannot see any price or other advantages if it were.

__________________
jack of all trades
Register to Reply
Power-User

Join Date: May 2013
Posts: 351
Good Answers: 22
#8

Re: Three Phase Toroidal Transformer Design

10/17/2013 11:36 AM

A simple toroid will not work, but in a way the old shell-form transformer cores like Westinghouse used could be considered a form of 3 phase toroid. This simply has a straight section where the winding is. The core design allows for the magnetic coupling of the 3 phases. A shell form transformer has some advantages but is very expensive to manufacture. A 5 legged core is simpler and is usually used if those advantages are needed.

Register to Reply
Register to Reply 8 comments
Copy to Clipboard

Users who posted comments:

4wsilver (1); dvmdsc (1); GW (1); jack of all trades (1); PWSlack (1); redfred (1); truth is not a compromise (2)

Previous in Forum: Forward Converters   Next in Forum: Terjem

Advertisement