Disc flyback / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Disc flyback

previous 1 2 3 next

Move Thread

LAN_403

nOg

Sun Jul 24 2011, 05:02AM

Registered Member #4011 Joined: Mon Jul 18 2011, 08:14AM
Location:
Posts: 12

Hi Newton Brawn,
Yes, the Vladmiro Mazzilli schematic (sorry, incorrected typing).

I just broke my bigest ferrite that I had. (left)

NEW one insteed of broken core. Look smaller. but weight is a litle bit looser.

Here is my NEW ferrite core drawing.

Can I repair the core?

Regards,

EDIT: The windor wider is 14mm.
In core drawing, pls cut ZERO off, I means 160=16mm, 100=10mm, 320=32mm

Forty

Sun Jul 24 2011, 05:52AM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

yes. use cyanoacrylate superglue.

Patrick

Sun Jul 24 2011, 06:15AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

nOg wrote ...

Can I repair the core?

Regards,

yes, use super glue, since youll have a gap (0.02" to 0.050") in the core anyway, the tiny super-glued cracks wont matter much.

nOg

Sun Jul 24 2011, 01:30PM

Registered Member #4011 Joined: Mon Jul 18 2011, 08:14AM
Location:
Posts: 12

Super glue. Great, I have.

So, what does the gap in core effect on transformer?

Pinky's Brain

Sun Jul 24 2011, 01:58PM

Registered Member #2901 Joined: Thu Jun 03 2010, 01:25PM
Location:
Posts: 837

AFAIK, in a true flyback the gap is there to increases energy storage. In a push/pull setup it gives you a little more margin for error with flux walking.

Newton Brawn

Sun Jul 24 2011, 02:56PM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

nOq

Yes, you can repair the ferrite core with superglue. No electrical-magnetic problems.

In your Mazzilli or other push pull converter, the air gap do not help, just is something that shall be avoided. However, in fly back converter the air gap is a requirement.

For Mazzzilli, make sure no air gap (or at least gap smaller than 0.05mm.).

It should be noted that some ferrite cores for fly back are manufactured with one leg 0.5~1.0 mm shorter than other 3 legs, in such way when the core is assembled the gap comes automatically .

I have cut 0.5-1.0 mm of the core leg in order equalize the lenght of legs, eliminating the gap. To grind use carbite sandpaper#100 (black one)

I think you need one ferrite core with bigger window to allow the assembly of the secondary coil. You can find a TV or monitor in the street or in the "Environmental Day Party " for free.

Regards

Newton

By the way, what kind of measuring unit did you use for the dimensions of you sketch ?? Shall I divide the dimensions by 10 to get the dimensions in MILIMETERS ??

I have tried to post a drawing as you have posted in above reply. No succes. Can you tell step by step the sequence to post a picture ?

Thanks

Newton

nOg

Sun Jul 24 2011, 04:20PM

Registered Member #4011 Joined: Mon Jul 18 2011, 08:14AM
Location:
Posts: 12

Hi Newton Brawn,

Refer to your shemetic

here.
I understand how important for inslutor over core. And what's necessary for Winding Form inslutor?

Thanks I'm going to tv repair shop tomorrow.
I can find the bigger window, 18mm at here. or Can I cut the core and glue it together?

Something like my drawing, should divide by 10.

For the post, I use Window Paint Programme, paste the picture that you want and add more another picture. Save at destop. Click at "attach file/image" below, insert your file and click at "Preview", So you can see your link.

Good luck

nOg

Mon Jul 25 2011, 04:09AM

Registered Member #4011 Joined: Mon Jul 18 2011, 08:14AM
Location:
Posts: 12

Thank you for your answer.

New size of core.

Hi New ton

It sounds that push pull converter is not suitable to make good ferrite transformer. Is it better to drive with GDT?
My GDT driver is very simple. Tl494 with 1:1:1 GDT. I ran DC flybacks. It's sitll ok but flybacks was very hot and damage even I put in transformer oil.

Regards,

Newton Brawn

Mon Jul 25 2011, 04:39AM

Registered Member #3343 Joined: Thu Oct 21 2010, 04:06PM
Location: Toronto
Posts: 311

nOq:

Thanks for the info re. posting a picture.

""" I understand how important for inslutor over core. And what's necessary for Winding Form inslutor? ""

To built the Winding Form Insulator, you need to make mandril (cilinder )18mm diameter x 13mm long . It coulde be a piece of wood, plastic or just cardboard/ masking tape cilinder.

1- cut a polyester ribow 13.2 mmX400mm, EDITED
2-apply a thin layer of epoxi on one face of the ribow,
3-coil (wind) the ribow over the mandril,
4- secure the ribow with 2~3 turns of wire #30 awg,
5 - remove the mandril, leave the epoxi dry for 1 day,
6- remove the wire .

From your second core sketch I am assuming that the window area (space for the secondary coil) is 18mm x 52mm. Please confirn.

If the window area is 18x52, we do not have space to house a 660 turns coil. The secondary shall be modified tobe constructed with 2 coils of 330 turn each.

The core at Mazzilli drive gets hot because the ferrite core works in the extreme of saturation. It shall be on for sort time only.
One way of reduce (but no eliminate) the core heating is increasthe value of the 47-200uH choque. Preference for air core choque. To solve this problem, the gates can be driven by a small ferrite beat 1:1:1 turn ratio. In this way, the main core works bellow the saturation (0.3T) and the small ferrite core saturate a lower current, providind the required feedback to the gates .

Next week I will be travelling no communication...

Regards

Newton

nOg

Mon Jul 25 2011, 07:15AM

Registered Member #4011 Joined: Mon Jul 18 2011, 08:14AM
Location:
Posts: 12

Yes, my window is 18x52mm.

Thanks for your help.
and enjoy your trip.

nOg

previous 1 2 3 next

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