Primary woes / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Primary woes

1 2 3 next

Move Thread

LAN_403

Meatball

Wed Dec 01 2010, 04:04AM

Registered Member #2401 Joined: Mon Sept 28 2009, 04:25PM
Location:
Posts: 74

Finally getting my own ZVS put together.

Considering that my inductor is 47uH, my psu is 25VDC and that I have #14 solid copper wire available, should I use it to wind my 4+4 primary along with those extra 3+3 turns?

Or should I find some stranded wire since its a heck of a lot easier to work with? Center tapping stranded wire comes with its own challenges though...

From reading these threads after searching:

I have come to no reasonable conclusions on my own.

Also, any reason why it would be wise to add another 470 ohm resistor in series with those already in the circuit- right away before testing?

Thanks guys, you've always been quite helpful!

-TT

Matt Edwards

Wed Dec 01 2010, 04:40AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

I don't have any experience with stranded and have heard bad things but maybe someone here has tried it. Anyway, you should be fine with 14awg solid if that is what is available. I have used 18awg with a 50v input.
As for the 4x4 and 3x3 I assume you are referring to this schematic?

If so, it is a great circuit as is with little to no changes necessary unless you wish to run a higher input voltage.
Make sure that your power supply can handle the needed current draw if you plan to use the flyback to draw arcs. I have gotten a few 6v lantern batteries so hot that the posts melted the plastic on the battery.
Oh, and if you need a good parts list let me know.

Adam Munich

Wed Dec 01 2010, 05:40AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

I replaced my "variable resistors" with 470 ohm 3w resistors and the ZVS works great even at 36V. So no, I'd say you don't need to add more resistors.

As for your primary, 18AWG works fine so I see no problem with 14. You can also get litz wire from computer monitors; the inductors on there are full of it. Litz wire is the stuff you want for high freq AC.

quicksilver

Wed Dec 01 2010, 04:00PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

IF you have a decent electronics store there are various size "taps" for simply cutting into shielded/insulated wire. They are OFTEN sold at places that have electrical contractors products and solve a whole lot of problems. they are great for everything from a center tap like you're talking about to a Primary on a TC. They are little plastic and steel snap-together items and come in wide variety of different sizes. They make a project very neat and tidy.

Meatball

Thu Dec 02 2010, 02:14AM

Registered Member #2401 Joined: Mon Sept 28 2009, 04:25PM
Location:
Posts: 74

Note: Stay away from lantern batteries..
I'll stick to my ATX PSUs in series..

I think I'll go find some 18 awg since it will be easier to work with than that nasty 14 awg.

Yes, I should have specified that I was going the Mazilli-2 circuit.

Too bad I don't have any old monitors around. I actually got this flyback from a local TV repair shop- not a TV.

Thanks for the wire tap suggestion, I'll go back to the shack and see what I can find.

I went ahead and just assembled it tonight. I tried to keep things symmetrical so I could keep things straight.

156204 1522327540959 1317690211 31221388 5033615 N

156204 1522327540959 1317690211 31221388 5033615 N

148567 1522327700963 1317690211 31221389 1202299 N

155154 1522327940969 1317690211 31221390 2967126 N

Cute little heatsinks, aren't they? I just want to gobble them up./

Wish me luck as I'm making a first test run tomorrow!

[Edit: Image size]

Matt Edwards

Thu Dec 02 2010, 05:04AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Not to sound negative but I give you about a 30 second run until you kill the fets with such small heatsinks. Good luck! Otherwise looks good!

Meatball

Thu Dec 02 2010, 05:08AM

Registered Member #2401 Joined: Mon Sept 28 2009, 04:25PM
Location:
Posts: 74

Really? I always hear how the FETs run cool. I see other people use larger heatsinks, and then say that they're overkill.

How much larger should I go?

I can always mount a nice fan or a blower next to the circuit. The thing fits in my pocket.

Adam Munich

Thu Dec 02 2010, 05:24AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

If you don't use a fan then you'll have to go big. If you do use a fan you can make things small and compact. For example;

This can run at 36V for about 20 seconds w/o a fan, with a fan nearly 5 minutes. The flyback would melt before the fets die of heat stroke.

ZakWolf

Thu Dec 02 2010, 08:37AM

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

i have slightly bigger heat sinks and i power my circuit with 10 amps at 15 volts and they never get hot

Adam Munich

Thu Dec 02 2010, 08:45AM

Registered Member #2893 Joined: Tue Jun 01 2010, 09:25PM
Location: Cali-forn. i. a.
Posts: 2242

Oh they will when you pump 36V at 44A through them like I do.

1 2 3 next

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