Are toroidal transformers best? - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th September 2006, 12:34 PM   #11
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi walker,
Unless you need the low form factor, or are running off 400 Hz avionics power, an EI core is best in the real world. They are less expensive to buy and the air gaps can help with common power line issues. Core saturation is a bigger problem with toroids. Not to mention the have poorer high frequency response, and that is what you want. You do not want to pass the high frequency hash too!

-Chris
  Reply With Quote
Old 8th September 2006, 01:57 PM   #12
walker is offline walker  Australia
diyAudio Member
 
Join Date: Nov 2001
Location: Perth West Australia
Send a message via ICQ to walker
This is a very old post that I put out to see if there was anything new under the sun. It appears not.
The task of the power transformer is to provide a low imedance voltage conversion, not to filter noise. Much of the information that has been published by manufacturers is marketing hype
wanting to convince buyers that cheaper transformers, (EI core) are better than torriodal transformers. If you buy this marketing hype they can sell a cheaper product at a greater price.
If you have noise problems filter it or better still isiolate it.
The core saturation argument makes no sense to me. If you get a power spike I'd rather have the core saturate to keep the sike out of the secondary rather than attempt to pass it on. The EI core will still EFFECTIVELY saturate as the leakage flux increases during a voltage spike.
Using a multimeter to read the magnetising current in the primary will not tell you how reactive the current is and therefore is of little use either.
Both transformers work well, but the torriodal has better supply regulation and lower stray flux. As I see it still the best choice.
Regards Walker
  Reply With Quote
Old 8th September 2006, 02:10 PM   #13
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi walker,
I can see this popped up again. Amazing.

I disagree completely with you with regard to the frequency response and saturation aspects, but that's okay. It is your opinion however, it's only fact to you. There are pros and cons to each type.

Quote:
Using a multimeter to read the magnetising current in the primary will not tell you how reactive the current is and therefore is of little use either.
That tells you what the magnetizing current and eddy losses are to the best of my knowledge.

A toroid has poorer heat transfer than an EI core. So you can use the chassis more efficiently to cool an EI core that is exposed.

So, on my planet, an EI core rules unless I need something flat.

-Chris
  Reply With Quote
Old 8th September 2006, 02:20 PM   #14
bscally is offline bscally  United States
diyAudio Member
 
Join Date: May 2005
Location: USA at the moment
Default Frequency response

One post made reference to the frequency response of the Transformer.
Now all things being equal there are differences in the frequency responses of the transformers, however things are not equal here.

EI cores and toroide cores are not commonly made out of the same core material

EI and toroid winding depths are very different due to the construction process.

EI and torroids have different core coverage percentages.

All this means that we are comparing apples and oranges.
Sure they are both fruit, but they are very different.


Brian
  Reply With Quote
Old 8th September 2006, 02:27 PM   #15
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi Brian,
We are comparing the performance of the finished, average product. It is not an apples to oranges comparison.

You are correct about core material, but if you can compare a Ford Mustang to a Chev Camero or Corvette, you can compare the performance of two different constructions of power transformers.

-Chris
  Reply With Quote
Old 8th September 2006, 02:27 PM   #16
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Quote:
Originally posted by walker
The core saturation argument makes no sense to me. If you get a power spike I'd rather have the core saturate to keep the sike out of the secondary rather than attempt to pass it on. The EI core will still EFFECTIVELY saturate as the leakage flux increases during a voltage spike.
The problem with saturation referred to is one of small DC component present in the AC network. This will more readily and asymetrically saturate a toroid or R-core transformer than any other type because they don't have an airgap. At that point one may get unexpectedly high levels of stray flux and hum from a transformer type that should be immune to it.
  Reply With Quote
Old 8th September 2006, 02:37 PM   #17
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Thanks ilimzn,
That was my point. Same thing can happen with secondary load imbalances.

Any effective DC flux from secondary or primary can cause larger problems with a toroid than an air gapped type.

-Chris
  Reply With Quote
Old 8th September 2006, 02:38 PM   #18
rdf is offline rdf  Canada
diyAudio Member
 
rdf's Avatar
 
Join Date: Jun 2004
Location: big smoke
Quote:
Originally posted by ilimzn


The problem with saturation referred to is one of small DC component present in the AC network. This will more readily and asymetrically saturate a toroid or R-core transformer than any other type because they don't have an airgap.
My brother in Ottawa has this problem with torroids connected to the local utility. Enough DC is present to make them buzz constantly.
Like most of these "which is best"-type questions the correct answer seems to me: "best for what?"
  Reply With Quote
Old 8th September 2006, 02:42 PM   #19
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi rdf,
Quote:
Like most of these "which is best"-type questions the correct answer seems to me: "best for what?"
Exactly, taking common local conditions into the consideration as well. Real life if you will.

"C" cores anyone? They seem to offer advantages of both types.

-Chris
  Reply With Quote
Old 8th September 2006, 03:16 PM   #20
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Quote:
Originally posted by anatech
"C" cores anyone? They seem to offer advantages of both types.
Yes, I like them very much but they are still larger than a comparable toroid. I have recently had some toroids custom made and had extensive talks with the manufacturer - and learned that there are indeed gapped torroids! In fact, you could think of this as 'round C-core' transformers - the core is glued together and the windings wound the same as a regular toroid. There are also C-cores that can be wound that way assuming the cores are fixed together.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS toroidal transformers royboy5033 Parts 0 22nd June 2009 08:46 PM
WTB/S/T: Toroidal Transformers - UK deadparrot Swap Meet 5 16th June 2009 09:34 AM
Toroidal transformers scottw Power Supplies 19 17th November 2006 10:09 AM
Toroidal transformers muddy Class D 3 24th February 2005 11:23 PM
Best Transformers (Encapsulated Toroidal or Open Frame Toroidal) Rixsta Pass Labs 10 23rd April 2004 03:41 AM


New To Site? Need Help?

All times are GMT. The time now is 11:06 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2