Ferrite Transformer / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Ferrite Transformer

1 2 next

Move Thread

LAN_403

Thomas W

Mon Jun 13 2011, 08:25PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

hello 4hv,
is there anywhere that will show me / teach me from the ground up how to design and build a high voltage ferrite transformer
and chooseing the core ect and how to set it up

thanks,
Tom Williamson

Dr. ISOTOP

Mon Jun 13 2011, 09:54PM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

If you want to learn the math and theory, there are assorted resources on the internet for power transformer design, though I don't know of any specifically for HV ferrite.
If you just want a working transformer, Steve Ward's site has a good log of a 3KW ferrite CCPS.
Things to keep in mind:
(1) Make sure to keep your V/turn low enough to keep the core out of saturation.
(2) Make the core large enough to avoid excessive heating (also helps with (1))
With (1) and (2) satisfied, all that remains is to design a secondary properly to avoid flashover; going under oil helps but is messy, potting in paraffin/epoxy works too, as does a properly designed open-air secondary.

ZakWolf

Tue Jun 14 2011, 06:59AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

sorry to hijack, but why make a thread just like this

Hi I was wondering if someone could point me in the right direction for buying a ferrite u core for a flyback, like a website some place where you have ordered before.

Many thanks

Edit: would this work? i haven't looked at all the information on it-

Ash Small

Tue Jun 14 2011, 07:18AM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

This link might be useful. Click on 'download':

cedric

Tue Jun 14 2011, 09:18AM

Registered Member #2941 Joined: Fri Jun 25 2010, 08:08AM
Location:
Posts: 143

LittleVenture wrote ...

sorry to hijack, but why make a thread just like this

Hi I was wondering if someone could point me in the right direction for buying a ferrite u core for a flyback, like a website some place where you have ordered before.

Many thanks

try this:

Dr. ISOTOP

Tue Jun 14 2011, 11:30AM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

TSC is a great place to get ferrite.
FYI they are out of stock at the moment, though

Thomas W

Tue Jun 14 2011, 06:48PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

is a ferrite core like this:
______________________
| ___... ___....___...___...|
| |.....| |......| |.....| |.....| |
| |___| |___| |___| |___| |
|_____________________|
1......2.......3.......4........5
possible to work?

1 = Secondary 10Kv
2 = Secondary 10Kv
3 = Primary coil
4 = Secondary 10Kv
5 = Secondary 10Kv

ignore the dots ;D

Ash Small

Tue Jun 14 2011, 09:30PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

Wind the primary under the secondary. use a bigger core.

I've got some of these:

Thomas W

Tue Jun 14 2011, 09:46PM

Registered Member #3324 Joined: Sun Oct 17 2010, 06:57PM
Location:
Posts: 1276

the specs im after are:

im going to have 7.2Kw in (230v @ 30A)

4 secondaries for series and paralleling depending on what power i want

with 100% efficancy i should get about

18mA per secondary at 10Kv

im probibly wrong somewhere though

im not sure if anything of this is possible im just stepping into the shore of transformer design and building

Dr. ISOTOP

Tue Jun 14 2011, 11:59PM

Registered Member #2919 Joined: Fri Jun 11 2010, 06:30PM
Location: Cambridge, MA
Posts: 652

Having wound (and destroyed) some secondaries lately, i would strongly advise against seriesed secondaries; it increases the stresses on the secondary insulation and just makes everything a pain to manage. For example, i hope you are not thinking about seriesing all 4 secondaries for 40KV out; its just not going to work. It's the old "I want to wind secondaries for 50KV" problem - it turns out that such secondaries are real hard to make...hard to insulate, excessive self-capacitance, etc.
i would use single-layer secondaries with the appropriate step-up ratio. 2 pairs of the large TSC International U-Cores should be good for 7KW; at 100 KHz you might be able to push them to 50V/turn without making them too sad.
What will you be using to drive this thing? 7KW is a lot of power; i would personally not try pushing a bridge of anything other than bricks to this power level; sure it can be done, but its rather finicky. Also, used CM400's are cheap.
You'll need a series resonant topology to ease switching losses.

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob