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 6th October 2002, 08:33 PM   #1
Myren is offline Myren  United States
diyAudio Member
 
Join Date: Oct 2001
Location: Maryland
Send a message via ICQ to Myren Send a message via AIM to Myren
Default DIY Transformer + Caps

Seems like most of the cost of amplifiers is in power supplies. So i'd like to roll my own superheavy duty transformer and caps....

Caps would be a nice big acrylic box, with thin layers of metal and some sort of dielectric. I was thinking maybe just thin cloth, with a dielectric oil. Lowest K value i can get away with/ Not sure what i'd use for the plates, thin is good, but cant be too fragile.

Safety is obviously an issue. Maybe some kind of metal reinforcement cage, and circuitry to detect breakdowns and provide an easier and safer route for discharge....

Now, where can i get a transformer core? I was thinking perhaps torodial.

Myren
  Reply With Quote
Old 11th October 2002, 05:17 AM   #2
CryingDragon
Guest
 
Sometimes u can find them on ebay BUT toridal is small what am planning to do is if you can get your hands on an old microwave you can take the giant transformer out of it and see these are made to supply 2000V at 2A! what you can do if u need less is take the high voltage secondary off and wind your own i'm sure you could make say a +- 70 at 10 amps at least. They are very large indeed but if you can get one it's a goldmine to do it yourself when you price heavyduty trandformers new. If you need any info on the rewinding email me and about the caps...I don't know because there are so many diffrent varables that you have to take into account plus most dielectirc oils are nasty to work with (fumes up the wazoo) and plus for the money you would spend on supplies to make your own caps i would bet you could buy some nice surplus ones.
  Reply With Quote
Old 11th October 2002, 07:18 PM   #3
diyAudio Member
 
Join Date: Aug 2002
Location: NY
It would be an interesting DIY project, but in terms of space and cost, I don't think making your own caps would really be worth it. You won't get the precision used in positioning the plates and dialectrics in most electrolytics, which means it'll be a lot bigger, and there are a lot of safety issues that you'll have to prepare against (as you mentioned), adding cost.

As for winding toroids, Micrometals makes some nice cores. I have print catalogs here, but I know they have a website too, so you should be able to search for it and find it.

As for rewinding a microwave transformer, why not just buy a toroidal core and wind that? It may cost more, since you have to buy the core, but in the long run, should end up being much better quality.
  Reply With Quote
Old 11th October 2002, 07:28 PM   #4
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
It definately is not worth it for making your own transformers. Sure you can buy nice big cores by themselves, but the overall cost won't be much cheaper. The enameled wire will cost you quite a bit if you can find it in anything less then a full spool. The main issue would be the quality. Without the machines, it would be hard to get a nicely would toroid. I have watched the guy at Victoria Magnetics, a company that makes toroids near me, make transformers, and he uses expensive machines which do all of the work. I could not imagine doing it by hand, especially with you wanting to make superheavy duty transformers. It is not easy to wrap 10ga wire evenly around a large core. I will try to take pictures of the machines next time I go down there, as they are quite interesting.

The only possibility that I would think would be feasable would to get a big old surplus isolation transformer and taking off some of the windings until you get it to the desired voltage.

--
Brian
  Reply With Quote
Old 11th October 2002, 08:06 PM   #5
diyAudio Member
 
Join Date: Aug 2002
Location: NY
We used to have a department where I work that did nothing but wind toroids, and it IS possible to do heavy duty toroids (big enough to handle many kilowatts, we design RF generators) by hand (or with some hand tools), and with enough patience, the quality is good, but eventually, we decided it would be cheaper to outsource them, and that's when we were buying cores and cables with bulk pricing...
  Reply With Quote
Old 11th October 2002, 08:26 PM   #6
CryingDragon
Guest
 
Quote:
Originally posted by BrianGT

The only possibility that I would think would be feasable would to get a big old surplus isolation transformer and taking off some of the windings until you get it to the desired voltage.

--
Brian
isn't that gonna be just as hard? *Yawns* Besides you can't simply take some wires off because big transformers are always potted in varnish to hold the windings in place and when you pull the wire off it flys everywhere,Very nasty mess and it also takes the insulation off the solid wire. i've rewound micro transformers and have been in highvoltage (tesla and the like) for a while now and i say when you can either get an old transformer some wire ($30 MAX,look at ebay) and take the time to rewind it and have a $200+ transformer for $30 it seems logical to me. Just thought i'd offer the idea.
  Reply With Quote
Old 11th October 2002, 08:51 PM   #7
diyAudio Member
 
Join Date: Aug 2002
Location: NY
Quote:
Originally posted by CryingDragon

you can't simply take some wires off because big transformers are always potted in varnish to hold the windings in place [/color]
Not always.
  Reply With Quote
Old 11th October 2002, 10:55 PM   #8
CryingDragon
Guest
 
Quote:
Originally posted by Narcisse91


Not always.
ok in every transformer i've taken apart.
  Reply With Quote
Old 12th October 2002, 10:10 PM   #9
diyAudio Member
 
Join Date: Aug 2002
Location: Clearwater, Florida
Remember that you will need approx. 450 turns for one square inch of core to get a reasonable flux density at 120 volts. Turns are inversely proportional core XSA, so if you have 3 sq. inches you will need 150 turns.
  Reply With Quote
Old 22nd March 2003, 12:12 PM   #10
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default Rewinding transformers

Found this article from 1983:
http://www.tech-diy.com/rewinding_transformers.htm
  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: (Australia) Evox Rifa caps and a 625VA transformer on eBay Cloth Ears Swap Meet 0 4th January 2008 06:43 AM
Question about caps on transformer primary speakerguy79 Power Supplies 2 24th April 2007 10:17 PM
Separating Transformer and Caps from Int Amp kptseng Solid State 3 28th March 2006 06:37 AM
caps for transformer.... Dj BASS AMP Solid State 4 27th July 2003 09:27 PM
question on transformer and caps JAZZ2250 Solid State 6 3rd August 2002 07:58 AM


New To Site? Need Help?

All times are GMT. The time now is 03:23 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