Almost perfect homemade flyback secondary / Projects / Forums

Forums

4hv.org :: Forums :: Projects

« Previous topic | Next topic »

Almost perfect homemade flyback secondary

previous 1 2 3 4 next

Move Thread

LAN_403

MRacerxdl

Fri Apr 01 2011, 04:42AM

Registered Member #989 Joined: Sat Sept 08 2007, 02:15AM
Location: SÃ£o Paulo, Brazil
Posts: 476

Very good! I tryed once to do that, but I didnt make so much turns. I think the output was some 2kV or less.

radhoo

Sun Apr 03 2011, 10:10PM

Registered Member #1938 Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 701

MRacerxdl wrote ...

Very good! I tryed once to do that, but I didnt make so much turns. I think the output was some 2kV or less.

This is where the small DC motor proves its utility: you wind the turns in no time.

You will need more then a few turns to take any advantage of this flyback shape.

Also the primary should be winded under the secondary coil.

jpsmith123

Sat Apr 30 2011, 04:35AM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

You do nice work, Radhoo.

Now that I found some pretty good epoxy (i.e., low loss, high dielectric strength, thermally conductive, low viscosity, low CTE), I'm going to try something similar to what you've done.

What I'm going to do is to use 0.75" x 0.007" glass cloth tape as layer insulation (say two layers of tape between winding layers to reduce capacitance and field stress) and 26 gauge magnet wire. That should give me about 45 or 46 turns per layer.

The tape should hold the coil together until it's encapsulated. And supposedly the tape readily absorbs the epoxy, so it should work out I hope.

Sulaiman

Sat Apr 30 2011, 05:29AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

I suspect that you will have to vacuum out all of the air if you want the potting material to fully impregnate the windings/insulation.

jpsmith123

Sat Apr 30 2011, 01:52PM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

A while ago I built a little vacuum chamber from an aluminum stock pot (with a heavy piece of acrylic for a lid), so I will probably use that, being that I have it, but if the epoxy is thin enough and the glass cloth tape absorbent enough, and the electric field is not too high, the coil might turn out ok even without vacuum.

Sulaiman

Sun May 01 2011, 10:25AM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3141

If you have any vacuum facility, use it.
Put a piece of your secondary copper wire in a glass of water and look at it. etc.
Wind a tiny secondary using your technique, pot it,
then when solid saw through and see what results are likely.

A few small tests can avoid frustration/a major loss of hair - drat!... too late.

jpsmith123

Wed May 04 2011, 07:56PM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

Well I just finished 7 layers and I had to stop...time for a beer or two or three...it's really getting on my nerves. It seems no matter how careful you try to be, it never goes exactly the way you want it to go...it never comes out perfect. It's utterly frustrating.

Marko

Wed May 04 2011, 08:09PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

hello,

jpsmith123 wrote ...

Well I just finished 7 layers and I had to stop...time for a beer or two or three...it's really getting on my nerves. It seems no matter how careful you try to be, it never goes exactly the way you want it to go...it never comes out perfect. It's utterly frustrating.

I'm just curious, why do you refuse to use the very method of winding described in this thread and persist on the frustrating method?

Marko

jpsmith123

Wed May 04 2011, 09:06PM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

Actually any method is frustrating to me because I'm sort of a perfectionist. It's something I impose on myself. I wish I didn't do it to myself...but I do.

The coil I'm winding right now is similar to what Radhoo did (i.e., it has no margins), but I'm trying to use a few layers of insulation between windings to lower capacitance and field stress. The idea is that the layer insulation (tape) will hold the coil together until it's potted.

If I tried to apply epoxy as I was winding it, as I understand Radhoo did, I'm sure that would end up being messy and frustrating, and I'd be drinking beer and thinking unpleasant thoughts about that, too.

In any case, I actually have a few coils wound already - using a different technique.

When I get the epoxy, which is hopefully soon, I'll have enough of it to encapsulate probably 4 or 5 coils, so what I'd like to do is pot several different types of coils at the same time and then later compare them.

jpsmith123

Thu May 05 2011, 08:44PM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

I finished a coil and here's what it looks like:

It's not perfect, but it's the best I seem to be able to do. Hopefully I'll be potting these things soon.

Luckily the tape holds it together well enough that it can be handled with reasonable care.

One stupid mistake I made was to not measure the diameter of the 26 gauge wire I used. Instead I looked at a wire table; with the result that instead of the 600 turns I wanted, I estimate I have only about 560.

previous 1 2 3 4 next

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