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Got new flybacks.. question :D

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LAN_403

Killa-X

Thu Mar 05 2009, 11:39PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

Got a shit load of flybacks today. You need to wind the outer core.....

1: Is this wound with magnet wire?

2: If I wanted to do a simple 555 12V 2A test on it, what might be the best coil ration. How many coils of wire should be put on the outer core to test them with my 555?

No for sure clue if all the flybacks work, but I just wanted to see one go :D

Mads Barnkob

Fri Mar 06 2009, 11:11AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Try with 6-10 turns, lesser turns give you higher voltage output but also stresses the mosfet more.

You can use magnet wire, isolated wire, soft or hard, multistrained etc, just be sure it can carry the current without burning :)

Download

Fri Mar 06 2009, 12:36PM

Registered Member #561 Joined: Sat Mar 03 2007, 02:46AM
Location: Adelaide Australia
Posts: 230

If you go with the 555 make sure the frequency is variable

Killa-X

Fri Mar 06 2009, 03:35PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

I ended up doing 7 turns with wire from a wallwart..But my trans former I use (12V 2A) HATES the wire. It thinks there's a short, and turns off. So I'm VERY limited with range. Only highest works. Else I can pull almost 1 inch arcs max..I already audio my arcs :D

Download:
Yes, My 555 box is a tight fit. It has 2 10K pots, Audio in jack, and a 3-setting switch. Pin2 to ground.. 1 = 1uf, 2 = 0.1 uf, 3 = 0.01uf. The 0.01uf at high pitch works best for my transformer.

Any ideas how I can stop my stupid 120V to 12V 2A Switch transformer to stop faulting? It
s annoying!

Dr. Dark Current

Fri Mar 06 2009, 03:51PM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Increase the running frequency, should be around 20-40kHz (=ultrasonic, above audible range). Also keep the duty cycle below ~60%.

Does your FET have sufficient voltage rating?

KLH

Fri Mar 06 2009, 06:42PM

Registered Member #1819 Joined: Thu Nov 20 2008, 04:05PM
Location:
Posts: 137

MadsKaizer wrote ...

Try with 6-10 turns, lesser turns give you higher voltage output but also stresses the mosfet more.

You can use magnet wire, isolated wire, soft or hard, multistrained etc, just be sure it can carry the current without burning :)

In order to make sure the wire can carry the current desired, use this skin effect calculator here (http://www.bcae1.com/trnsfrmr.htm) to find the AC resistance of the wire at your particular operating frequency. This is very important for the primary winding, since these are usually made out of thicker wire, and also because the current in the windings of a flyback transformer are ALWAYS highly discontinuous. Using thick wire at too high of an operating frequency can cause the AC resistance to dissipate too much power. As an alternative, you can use Litz wire or multiple parallel windings, both of which are made of a wire gauge where skin effect is not significant.

Killa-X

Sat Mar 07 2009, 06:12AM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

my mosfet is a 500V 15A or so rated. IRFP450 and 1 nanosecond switching rate.

I'll have to frequency test it......
I can get a max of 134.1 Khz at 44.7% duty cycle..

60% duty cycle went to 107.3 Khz

Mads Barnkob

Sat Mar 07 2009, 08:51AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Your 12V/2A wall smps is turning off because you draw more than 2A, find a bigger power supply.

Arcstarter

Sat Mar 07 2009, 05:27PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Find an old trashed big stereo! They have all you need. A large transformer with MANY taps, the bridge rectifier and the smoothing caps. My transformer has 102v center tapped, 34v center tapped, and an 8 volt winding. Good for 1.2kw and it weighs 15 pounds and is potted. On turn on, lights do not dim at all, and there is no humming. Also, when shorting one of the windings, it pulls TONS of current, which means it is powerful.

I have had a smaller one too, which was very helpful too.

Also, you can rewind a MOT.

Killa-X

Sat Mar 07 2009, 05:40PM

Registered Member #1643 Joined: Mon Aug 18 2008, 06:10PM
Location:
Posts: 1039

I just figured the wire was causing a 'short' in the line, since my switch will turn off when A: Theres a short, B: Frequency is too low

When I tryed my lionel (Heat-Short ability) it doesn't turn off at all no matter what, but its only 400ma.. I tryed a 19.5V drill battery and since it can't short, I was able to use and frequency, and i got over 1 inch drawn arc, near almost 2 inch o.O

I tryed my Dell transformer, 19.5V 4A. These are still switches. And 1 coil = short, wont go on. So, I got 2 flybacks. about 12 coils on each of them. Primary = parallel, HV = series. I can start an arc at 1 inch, and draw it to nearly 2 inches. With music, I can also get almost 2 inch musical arcs. Now heres the question.

The left knob on my 555. I beleive is a 10K from 12V. When its turned to the right, the arcs get longer (lower pitch, higher volts on the pin 3) commonly, this kills the switch transformers. So, I plug a mp3 player in. I can turn to ANY RANGE! It will NOT ever turn off the transformer. I can get longer arcs. Why is this? My music is on pin 5 to ground. Is it because its a higher frequency? It's already near 130Khz without the music...

Raw video of it. Didnt feel like editing.

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