Wiring your own... (mumble)... transformers - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 14th December 2001, 02:45 AM   #1
diyAudio Member
 
Lisandro_P's Avatar
 
Join Date: Oct 2000
Location: Argentina
Send a message via ICQ to Lisandro_P
Question Wiring your own... (mumble)... transformers

Well, this is the situation: i need a 18-0-18v 400 (at least) VA transformer for my dual '96 JLH. This is not a "standart" voltage, so it has to be custom built. After some averiaguations, it's arround $40-$50 for an E-I. Double that for a toroidal..

Now, my dad asked "100 bucks? Why don't you just build your own? We made our own transformers all the time in University"... good question The maths behind the turns are not complicated, but, in practice, has anyone tried this out? I'd like a toroidal; it's a bit messy to work with, but since we're talking a few hundred turns i can live with that. E-I is out of the question; eddy currents are not easy to be made small enough on homemade transformers... or not?

So... Comments? Links? Prices? Thanks in advice!
  Reply With Quote
Old 14th December 2001, 04:10 AM   #2
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
So get your Dad to wind them...
Okay, maybe not.
There have been several threads on this. Do a search and see if you can scratch up some basic info. I think there were links to sites with info. However, I think your basic problem is going to be finding cores, whether EI or toroid. Once upon a time, they were more available...nowadays, they're scarce.
One option is to take a transformer of known VA, strip the secondary (leaving the primary) and rewind an entirely new secondary. Keep a count of the turns you remove so as to be able to calculate the turns you'll need to get the right voltage. The current rating, of course, will depend on the gauge of the wire you use. I've done this. It works well, but is tedious.
Another possibility is to take surplus transformers that have a slightly higher voltage (say, 20V) and simply remove a couple of turns.

Grey
  Reply With Quote
Old 14th December 2001, 05:05 AM   #3
diyAudio Member
 
Lisandro_P's Avatar
 
Join Date: Oct 2000
Location: Argentina
Send a message via ICQ to Lisandro_P
Quote:
Originally posted by GRollins
So get your Dad to wind them...
Okay, maybe not.

(...)
He'd be happy to supply me with literature on the subject, but i beleive that's about it

Today i'll storm the local transformer winding shops and see what i can find... the idea on the old transformer is good, specially if the VA ratings are met. I'll see what i come up with... my idea was to spend $20-30 for a ring core and the wire.

So, besides doing the maths well, picking a suitable wire & core, keep the turns tidy and covering as much as the core as posible, is there anything i should be aware of?
  Reply With Quote
Old 14th December 2001, 05:16 AM   #4
diyAudio Member
 
Join Date: Feb 2001
Location: Columbia, SC
Local transformer winding shops?
Wish I had a few of those.
Nah, sounds like you've pretty much got it covered. Just take it slowly and do a good, clean job. You'll be fine.

Grey
  Reply With Quote
Old 14th December 2001, 05:22 AM   #5
diyAudio Member
 
Join Date: Aug 2001
speaking of DIY transformer winding...I was even tempted to get a RUFF toroid winder but seems that their prices are quite steep
  Reply With Quote
Old 14th December 2001, 11:59 AM   #6
Alex M is offline Alex M  United Kingdom
diyAudio Member
 
Join Date: Apr 2001
Location: Hampshire, UK
I've just rewound a 500VA toroid. This was
originally 25-0-25V, but I wanted 35-0-35V plus a
low-current 45-0-45V winding.

It's a perfectly straightforward job, but it does
take forever to get twenty metres of 1.6mm wire
off the core and then wind nearly thirty metres
back on (and then 35 metres of the thinner stuff
on top). It's also a real pain to get the turns
tight and tidy, especially with the thicker wire.

cp642, what does the Ruff tool do?

Alex
  Reply With Quote
Old 14th December 2001, 12:33 PM   #7
diyAudio Member
 
Join Date: Aug 2001
Alex...the Ruff tool is a toroid winder for more info check out www.ruff-inc.com....... a good investment if you in some serious DIY stuff and the cash to spare
  Reply With Quote
Old 14th December 2001, 08:15 PM   #8
blmn is offline blmn  Brazil
diyAudio Member
 
blmn's Avatar
 
Join Date: Feb 2001
Location: .
Lisandro,
  Reply With Quote
Old 14th December 2001, 08:21 PM   #9
blmn is offline blmn  Brazil
diyAudio Member
 
blmn's Avatar
 
Join Date: Feb 2001
Location: .
Lisandro,

Its not so difficult to rewind an old transformer, specially if you find one with no veneer in the bobin.

If you make a good mounting job, there is no problem about leakage or eddy current.
  Reply With Quote
Old 15th December 2001, 12:40 AM   #10
jduncan is offline jduncan  United States
diyAudio Member
 
Join Date: Nov 2001
Location: Boston, MA, USA
Send a message via AIM to jduncan
hold on......

if you were honestly concerned about $100 being the price for an 18-0-18 400VA toroid....they're not that expensive.

Plitron (to name one company...) make very good toroids that are $53 for all their 400VA toroids....This is pretty reasonable...
  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
Wiring Transformers Using The Series Parallel Scheme OMNIFEX Power Supplies 2 18th May 2009 02:55 AM
wiring two transformers to two dual rectifer units larryg Chip Amps 13 14th February 2009 04:09 PM
Help identifying a pair of output transformers and power transformers mjk130 Parts 3 30th January 2009 10:44 AM
Focusing on wiring cable for gainclone!!!Share ur experience in wiring cable.... thomgun_lc Chip Amps 38 31st August 2005 02:46 PM
I'm wiring my 4 channel 8 parallel LM4780 boards... check my wiring :) Audiophilenoob Chip Amps 9 16th August 2005 04:37 AM


New To Site? Need Help?

All times are GMT. The time now is 09:03 PM.


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