Re: SMPS Flyback question
Dri0m, Sat Jun 09 2012, 01:46PM

too complicated? build it like i did few years ago



it looks the same as on schematic :)

Re: SMPS Flyback question
zippotix, Sat Jun 09 2012, 02:07PM

You don't mind if I'll save your ZVS pic? For future reference ;)? I know it's considered simple circuit, but it looks like black magic to me, lol. The coil in the bottom is inductor, yes? It doesn't have to be toroidal?

Re: SMPS Flyback question
brandon3055, Sat Jun 09 2012, 02:34PM

For my first zvs I just atached the mosfets to a heat sink (with insulators) and soldered the other components straight to their leads

Re: SMPS Flyback question
Antonio, Sat Jun 09 2012, 02:48PM


Without heat sinks? Would operate at very low power only.

Re: SMPS Flyback question
TwirlyWhirly555, Sat Jun 09 2012, 03:13PM

ZVS is failry easy to build , i usally solder stright on Fets , But heat sinks are needed , as head disspation can be high sometimes unless run on low powers as someone said ,

My ZVS heat sink is 1mm x 20mm x 20mm aluminium plate as my max i run my ZVS at is 50 watts in .

Re: SMPS Flyback question
Dri0m, Sat Jun 09 2012, 04:53PM


well, it was my first ZVS i built (and actually second electronic device i ever built), here are photo of my ultra-compact ZVS IV:



I built it this morning. This little one is made mainly for HV and coilgun chargers, but can switch up to 1kW of power (tested)

Re: SMPS Flyback question
brandon3055, Sun Jun 10 2012, 01:23AM

I built it this morning. This little one is made mainly for HV and coilgun chargers, but can switch up to 1kW of power (tested)
[/quote1339290251]

That's a good little unit you must have used 260's?

This is mine I built it for general HV use its max input is 45v don't know the current draw its controlled by a PWM which is the only thing that gets hot the two small sinks in the fets don't even get warm

Re: SMPS Flyback question
Dri0m, Sun Jun 10 2012, 06:44AM

That's a good little unit you must have used 260's?

I used IRFP250N. But zener diodes in this ZVS are probably too weak (lol 5W :D), they can't handle voltage peaks and ZVS is now dead :D i will put there some neon glows, it will help :)

Re: SMPS Flyback question
zippotix, Sun Jun 10 2012, 09:22AM

But does anybody know the answer to my original question :)?

Re: SMPS Flyback question
Antonio, Sun Jun 10 2012, 06:14PM


Your first construction technique is much better than the (sorry) mess of the second.

Re: SMPS Flyback question
Antonio, Sun Jun 10 2012, 06:16PM


Without a complete schematic there is no way to say anything.

Re: SMPS Flyback question
zippotix, Mon Jun 11 2012, 08:24AM

I can't find any schematic of it. Would a photo of the circuit do?

Re: SMPS Flyback question
Dri0m, Mon Jun 11 2012, 12:42PM


yep, it is, and ZVS V will look the as ZVS II, because i will make it run for 350VDC from outlet with IGBTs, and i don't need that thick cables for higher voltage, but i need massive heatsinks, just like on ZVS I and II :)

Re: SMPS Flyback question
Dri0m, Mon Jun 11 2012, 12:44PM




I recommend to use 15V 5W zeners, 5W 470R resistors, 1W 10k resistors, UF5408 fast diodes, and 5x220n >250V capacitors.

Re: SMPS Flyback question
Patrick, Mon Jun 11 2012, 02:02PM

if you cant find a schematic, you shoud be able to draw a schematic of your own, as built.

Re: SMPS Flyback question
Newton Brawn, Tue Jun 12 2012, 03:00AM

Hi Zippotrix !

These guys are sad !

Let me try to answer your qestios:

1- the assembling lay out posted by DriOn is very apropriate for you . _My only comment is to put one heat sink on each IRFP. It could be a alumminun plate 100x100x1.0 mm ( or a stack of several 100x100mm plates taken from bier can ).

2- No, it is not nescessary to be a toroid. The coil in the botton is a inductor, It is a ferrite rod coilled with several turns of wire. The inductor could be done indindg some wire in a ferrite toroid . Or even 100 turns of wire in a 25 mm PVC water pipe. I love air core indictors, as wire coiled in pvc pipe because it is very simple to calculate and no saturation of core.

In order to you to assembly and understand the circuit you need the a circuit schematic that show the electrical relationship between the conponents. The suggestion offered by DriOn on Mon Jun 11 2012, 08:44AM is ok.

The lay out or picture as shown Sat Jun 09 2012, 09:46AM just show the position of the components in the space, some wiring between the components.

Of course the connections in the lay out are to follow 100% the circuit squematic.

Regards

Newton

P.S Dont be surprized that Your 11V 200W halogen transformer to drive a flyback is almost the same that a good ZVS !

Re: SMPS Flyback question
zippotix, Tue Jun 12 2012, 12:23PM

Hello Newton, many thanks for your answer :). I decided to give it a shot, ZVS I mean. The halogen transformer I'm using is pretty strong (for me anyways:P, certainly stronger than 3055 loaded with 12V). Arcs strike at about 3cm, and can be stretched to about 5-6cm. They're not purple, but yellowish, but not as hot as ZVS. My only problem right now is getting something to power the ZVS. As I understood, it needs minimum of 12V/10A?

Re: SMPS Flyback question
brandon3055, Tue Jun 12 2012, 12:59PM

You could use a boost converter to give you between 15v-20v from your halogen transformer or you could rewind an MOT

Re: SMPS Flyback question
Dri0m, Tue Jun 12 2012, 02:06PM



sometimes, when my batteries are extremely overloaded, ZVS ran for 7V, and it was fine, so, you transformer is OK :)

Re: SMPS Flyback question
zippotix, Tue Jun 12 2012, 06:26PM

Yea, but I would like to have some juicy arcs. Like here . I'm wondering what's that sound as the electrode is withdrawn, you can hear a cracky noise? Why it's not happening with other drivers, but only ZVS?

Re: SMPS Flyback question
Dri0m, Wed Jun 13 2012, 05:26AM



becuase //probably//, the arc collapses, but because of highly ionized air, it will instantly catch again, and that sound is spark.

Re: SMPS Flyback question
zippotix, Wed Jun 13 2012, 04:19PM

Dri0m, that makes sense. I'm planning on using components from this circuit ( I have no clue where to get indcutor though, everything else is avaible.

Re: SMPS Flyback question
Dri0m, Fri Jun 15 2012, 12:20PM


don't buy inductors, the ones that fit into ZVS are quite expensive, buy only ferrite core and wind your own ;)

in case if you don't have LC meter:
1. get ferrite toroidal core 25mm outer dia, 15mm inner dia
2. wind 15-25 turns.

if you wind more turns, you will get higher but "shorter" voltage peaks; low current and higher voltage
if you wind less turns, you will get lower but "longer" voltage peaks; higher current and lower voltage, but arcs are more stable

Re: SMPS Flyback question
m4ge123, Fri Jun 15 2012, 07:12PM

Actually, the inductance of the input inductor shouldn't affect anything, but it should be at least 10x the inductance of the primary coil, preferably close to 100. An iron powder core is best for this.

Re: SMPS Flyback question
zippotix, Sat Jun 16 2012, 10:10AM

Thanks, so I will wind my own :). I think I have toroidal ferrite lying somewhere. While I'm waiting for delivery of ZVS parts, I'm wondering how to limit current output from SMPS? Some ballast? A LED diode placed between SMPS output and flyback primary?

Re: SMPS Flyback question
Sulaiman, Sat Jun 16 2012, 11:43AM

To have a go at the original question;
Can you describe how you are driving the flyback with the halogen transformer?
especially how many turns of wire did you wind around the core?

Re: SMPS Flyback question
zippotix, Sat Jun 16 2012, 03:21PM

Hello Sulaiman. It's a 11,5V 200W dimmable electronic halogen transformer. As far as I know, it outputs at frequency good for driving a flyback, so I guess it's about 15-20kHz. I just wound a new primary on the flyback, depends on the mood, right now it's 7 turns, but it can handle 3 turns too (although primary wire starts to smoke, insulation is melting after a while), and connected to halogen transformer output.

Re: SMPS Flyback question
Sulaiman, Sat Jun 16 2012, 04:46PM

Reducing the number of turns was going to be my suggestion ....
suppose you want the full 200W at 11.5V, current = 200/11.5 = 17.39 Arms !
You need thick wire - but NOT single strand (e.g. magnet wire)
Ideal would be several thin strands of 'magnet' wire twisted together,
or a few normal multi-strand household wires in parallel,
or some flattened copper pipe etc.

For more output reduce the number of primary turns,
for even more output put a capacitor across the primary winding
so that the primary inductance resonates with the primary capacitance at the output frequency of the halogen transformer.
Since I guess you don't have the equipment to measure inductance, frequency etc.
it will have to be trial and error.
Use film capacitors .. polypropylene foil/film as you would have to for a 'zvs' primary.
Look for capacitors that have KP, MMKP or MKP printed on them.
You should get output comparable to a 200W zvs !

I have to say this .... 200W at 10's of kHz and tens of kV is VERY dangerous.

Re: SMPS Flyback question
zippotix, Sat Jun 16 2012, 05:41PM

Thanks for answer Sulaiman. But where to place a cap? Do you think 0.68uF MKP would do?

Re: SMPS Flyback question
Sulaiman, Sat Jun 16 2012, 05:59PM

Since neither you nor I know the halogen transformer frequency
or the inductance of your primary on the flyback transformer
I can't give a definite answer,

If 0.68 uF is what you have, use it,
before you make a 'good' primary
try 8,7,6,5,4... turns with the 0.68 uF capacitor, see if there is a 'sweet spot'
the capacitor should be in parallel with (across)
the flyback primary and halogen transformer output

If the halogen transformer can survive, a series-resonant arrangement
would probably get the most power output
with the capacitor in series with the flyback primary,
if the resonant frequency matches the halogen transformer output frequency
you will get the most power throughput
you may also destroy your flyback secondary due to over-voltage. ;)

Re: SMPS Flyback question
zippotix, Sat Jun 16 2012, 07:41PM

Something like this?

Re: SMPS Flyback question
Sulaiman, Sat Jun 16 2012, 10:33PM

Yes,
Exactly like that.

Re: SMPS Flyback question
Dr. Dark Current, Sun Jun 17 2012, 01:12PM

The capacitor in *parallel* to the halogen transformer output will most likely kill it. The output is a square wave and you know what a capacitor supplied with a square wave voltage does.

Re: SMPS Flyback question
Ash Small, Sun Jun 17 2012, 01:18PM

Platinum has quite a bit of experience with this setup, but he has managed to destroy several halogen transformers. He has some old threads with huge arcs somewhere.

EDIT: found a link to one of his threads on the subject:

Re: SMPS Flyback question
zippotix, Sun Jun 17 2012, 05:29PM

So it's a bad idea to connect cap to it? Ash Small, I saw those videos, thanks. The output of the halogen transformer is AC, I thought it's sinusoidal?

Re: SMPS Flyback question
zippotix, Sun Jun 17 2012, 05:50PM

By the way, which zener should I buy for ZVS? I think 12V should do? And 10k resistor, should it be of any specific type? Or just normal 10k 1W one?

Re: SMPS Flyback question
Dri0m, Mon Jun 18 2012, 05:40AM


some people says that ZVS with 12V ZD doesn't work (neither to me), buy both 12V and 15V and try it. The 10k resistor can be any 1W one

Re: SMPS Flyback question
zippotix, Mon Jun 18 2012, 11:26AM

Dri0m,I have this zener diode, it's not typical straight design but I've been told it works the same I have only 0,25W 10k resistor, it's too weak? By the way, 0.68uF is the same as 680nF, right?

Re: SMPS Flyback question
Dri0m, Mon Jun 18 2012, 04:19PM


that diode looks old. 0.25W resistor will probably heat, but not overheat, so it should work

...and yes... but capacity is not critical, i'm personally using 4uF cap, higher capacity = higher power, but 680nF is good

Re: SMPS Flyback question
zippotix, Mon Jun 18 2012, 05:32PM

Sorry for being such a pain in the a$$ :). I saw your video of ZVS, and what caused the fail of flyback? Secondary got burtn, yes?

Re: SMPS Flyback question
Newton Brawn, Tue Jun 19 2012, 03:11AM

Zippo !

The capacitor MUST BE IN SERIES with output uf the halogen transformer !

If you put the cap in parallel with the hallo trafo >> PUF! the cap or the hallo is finished !

Regards

Newton

Re: SMPS Flyback question
Dri0m, Tue Jun 19 2012, 05:31AM


well, I had 50kV on output, and arc started directly on DST and burned it's surface, but it can still work if i clean it :)

Re: SMPS Flyback question
zippotix, Tue Jun 19 2012, 01:50PM

Oh, well, but these arcs were insane :). Hey Dri0m, I can't get torroid ferrite, but I have broken flyback core. I was thinking that it could work similar as your inductor. I'm posting the pic, please tell me what you think

Re: SMPS Flyback question
Dri0m, Tue Jun 19 2012, 02:56PM


You can use any ferrite core, but idk how many turns, i think it should be >50 turns. i don't have any free DST ferrite, so i can't measure it.

Re: SMPS Flyback question
zippotix, Tue Jun 19 2012, 06:43PM

Hm, ok. One last question (I hope, lol); can I power the ZVS with halogen transformer if it's AC?

Re: SMPS Flyback question
zippotix, Wed Jun 20 2012, 03:59PM

Nevermind, I assembled the zvs as on the circuit, but I'm sure I did something wrong. All it gives is slight humming and when I touch the HV ground pin it sparks with barely visible very small "arc". Guess I'm not cut out for electronics ;), I give up.

Re: SMPS Flyback question
brandon3055, Wed Jun 20 2012, 11:38PM


Don't give up just try again it onec took me 4 hours to find a faulty trimmer but that's no reason to give up
Btw sounds like its working maby there's not enough power how many primary turns are you using? Also I get 1mm arks when I fry the transformer but that seems unlikely in your case since you haven't had it running yet but try changing it anyway maby the tv you got it from had a bad flyback

Re: SMPS Flyback question
zippotix, Thu Jun 21 2012, 07:55AM

Destroyer of mosfets, thanks, I'm gonna give it another shot. I dismantled the whole thing and will start from the begining. I tested flyback with SMPS, and it works like nothing happened. I'm certain I connected the mosfets correctly, but messed something up with 4007's and zeners. Maybe it's like that cause I plugged 11VAC in there, and it runs on DC only? Oh, and inductor (self wound 25 turns, toroid from PSU) gets very hot after a while of "running". Primary on flyback is 6+6turns. Oh, and flyback was bought new at the local RTV shop :).

Re: SMPS Flyback question
zippotix, Sun Jul 01 2012, 05:34PM

Ok, I've got it to work last week. At 36V it really kicks a$$, but overheats a bit, I'll just get better heatsink. But I'm still curious about the original question. I tried adding a .68uF cap to the halogen transformer output and it didn't affected the HV output. Maybe a smaller capacity capacitor would do better? What do you guys think?

Re: SMPS Flyback question
brandon3055, Sun Jul 01 2012, 10:52PM

In not shore about the cap but I had another thought on the topic of using a halogen transformer to run a flyback would it be possible to remove the transformer from the halogen transformer (in my experience usually a toroydal transformer) and use the inverter to run the flyback directly? That way your not dropping 240 or whatever your mains is to 12 andthen back up if you want isolation you could still rewind the halogen transformer secondary to put out higher voltage maby 20v-30v

Re: SMPS Flyback question
zippotix, Wed Jul 04 2012, 04:56PM

Thanks for suggestion. I'll try to disassemble it and see what can I do. This might work :). But my ZVS failed, or rather the MOSFET failed. I switched it on and off, with 2 car batteries powering it, and suddenly irfp250 white arced to the other fet, killing it too, as if batteries created some voltage spike. What the hell? Looks like I'm gonna rebuild it again, this time i'll use this schematic . What do you think Destroyer? This schematic looks different from others, wold it work?

Re: SMPS Flyback question
brandon3055, Wed Jul 04 2012, 09:45PM

Looks exactly the same to me

Re: SMPS Flyback question
zippotix, Thu Jul 05 2012, 05:19PM

But resistors and zeners are placed directly on MOSFET's teeth. I thought that wouldn't work? Also, I know that resistors are bipolar, non directional or whatever :P, but are zeners and fast diodes bipolar?

Re: SMPS Flyback question
TwirlyWhirly555, Thu Jul 05 2012, 07:40PM


Nothing Wrong placing The Zeners / resisters on the mosfets pins . thats what i do and have never had any issues .

The fast dioes will only conduct in one direction under normal conditions .

As for the Zener under normal operation it will conducit in on direction as normal . But if the zeners break down voltage is reached in the other direction then it will condcut aswell

So in the ZVS circuit the anode of the Zener is connected to mosfet source pin ( At 0 V ) then the cathode is connected to Gate . under normal operation the zener will not conduct . But say the Zener was a 15 Volt Rated one if the potential between gate and source excedded this valve then the zener would conduct and clamp the voltage to 15 protecting the mosfet gate from damage .

Think Thats how it goes anyway :P

Re: SMPS Flyback question
zippotix, Tue Jul 10 2012, 10:32PM

About the schematic I posted a 2 posts ago, are you sure it would work? On every other schematic the ground is connected to + through the 10k resistors and zeners but not on this one. Also the author of this schematic wrote "If you did that then you should take a look on the diodes that use your negative
peaks to switch of the opposite mosfet.It must be soldered from the one mosfets drain
to the other mosfets gate to switch it off at the zero voltage moment and vice versa
for the other mosfet. Take a look on the real picture it looks like a X shape." but on his schematic both UF diodes go to MOSFETs drains. A bit confusing to me.

Re: SMPS Flyback question
brandon3055, Tue Jul 10 2012, 10:43PM

No it all looks fine its the same as any other zvs just remember the diodes on the mosfets are zeners

Re: SMPS Flyback question
zippotix, Tue Jul 10 2012, 10:55PM

Sure, ill remember. Im gonna build it tomorrow, or rather solder it together. Destroyer, you seem to have destroyed many mosfets ;P. What do you think, what caused mosfet fail? Too much current? It even gave a bang. You had something like that happen to you?

Re: SMPS Flyback question
brandon3055, Wed Jul 11 2012, 12:42AM

I killed most of my mosfets in my sstc and a couple in my zvs induction heater (ok more then a couple ) but I have never blown any in my flyback driver possibly because it in controlled by a zvs

Edit: this is the PWM I used to controle my zvs it did need a few modifications one irfp250 with large heat sink, replaced the input resister to around 200 ohm can't remember exactly and a small cap on the output about 1000uf the max input voltage under load is about 40v this is using the higher voltage version of the zvs with 15v zeners and 1k gat resistors

Re: SMPS Flyback question
zippotix, Thu Jul 12 2012, 06:18PM

Oh, looks a bit too complicated for me, for now at least :P. I've rebuilt zvs today, using the schematic I posted few posts ago, and well, it works much better, the arc is more stable. I'm little worried about heatsinks, I got them from old PC, they don't look like typical heatsinks, but are 3mm thick, and have thicker "heat dissipators", 16 of them.

Re: SMPS Flyback question
Jinkela, Wed Jul 18 2012, 02:38AM


A halogen transformer can be used to drive a flvback transformer.The method is quite simple!
Firstly replace the transistor with powerful MOSFET like IRFP460
Secondly replace the transformer with your flvback transformer, U can use the primary winds inside the flvback transformer
Third put a 100w 220V light bulb in series with the modified circuit(to prevent the MOS explode) and connect it to 220v to see whether it can work or not
If the light bulb is very bright, that means your circuit not working properly, maybe you need to change the ratio of the feedback tansformer in the halogen transformer PCB to make the circuit vibrate.
If the light bulb is not on or looks very dark, that means you already success 70%, now you can try to make arc from the flvback transformer, the light blub will be brighter when you making arc, dont worry
Finally the most dangerous part,connect the modified circuit to 220V directly!!!Usually it will be alright, but sometimes when you making arcs,the MOS will explode because it's too powerful!!!!!!!!

Re: SMPS Flyback question
zippotix, Thu Aug 09 2012, 06:37PM

I was wondering if anyone was or is using "industrial power supply" to power ZVS? I mean something like this
I'm thinking about buying one, as charging car batteries is kinda annoying, and takes quite much space. Do you think output of this thing needs rectification?
EDIT: Jinkela, thanks for input, but I think it's not worth the effort ;). I'm afraid I would destroy something in the process.

Re: SMPS Flyback question
Harry, Thu Aug 09 2012, 07:19PM

Nope it is already rectified, you can see the -V and +V outputs, implying it is DC. I don't know of anyone who uses one but plenty of people use PC power supplies. I reckon it would work as long as you don't exceed the rated current output

Re: SMPS Flyback question
zippotix, Sat Aug 11 2012, 11:47AM

The site says it has in built overload protection, overvoltage protection etc. BTW, I tried to kill a electrolytic cap (330uF 200WV)with a flyback and failed. I forgot about it and left it on the bench, and next day I grabbed it and it shocked me. Not very smart of me, I know. Anyway, I used some online calculator, and according to this, the cap was charged to 66000 Joules, and 6.6 Coulombs. Is that even possible? Isn't that much energy instantly lethal?

Re: SMPS Flyback question
Dr. ISOTOP, Sat Aug 11 2012, 12:03PM

The cap charging load probably caused the flyback output to sag below 200V; a 200WV electrolytic will die and vent not far above that.

Re: SMPS Flyback question
zippotix, Sat Aug 11 2012, 12:09PM

Oh, so it won't charge above 200V? It gave me a good jolt, when shorted on metal plate it gives a loud bang and left 2 small holes. Is it relatively safe?

Re: SMPS Flyback question
brandon3055, Sat Aug 11 2012, 03:58PM

I think it is highly unlikely to get a lethal jolt from a capacitor if the charge is only traveling through your hand also if you can measur the resistants of your hand you should be able to use ohms law to find out exactly how much current you were exposed to (about 30ma is lethal) but again that might only be if it is traveling through your body but I don't recommend testing this theory haha

Re: SMPS Flyback question
zippotix, Tue Aug 14 2012, 11:36AM

Thanks Destroyer. Guys, I'm making a high current mot transformer, and while cutting off the secondary, I accidently nicked primary, like this Is there anything I can do?

Re: SMPS Flyback question
brandon3055, Wed Aug 15 2012, 01:46PM

I have done that a cople of times I found a good way to fix it is just to make shore the windings aren't shorted then put some super glue on the damaged part followed by a few layers of tissue paper and that seems to work ok for me but you should waight to se what others have to say first

Re: SMPS Flyback question
zippotix, Thu Aug 16 2012, 11:58AM

Yup, will try it and report how it works. If not, I can get another mot, plenty of microwaves near dump site. I don't know much about mots, but if I understand well, the current draw must be limited to not break the fuse (mine is 16A)? Is running a mot in resonance with 2 or 4 hv caps reducing the current draw?

Re: SMPS Flyback question
Sigurthr, Thu Aug 16 2012, 01:09PM

A mot in resonance would draw MORE power than an off-the-shelf (or out of the waste bin, haha) MOT. Grab a second MOT and short the HV side and wire the primary in series with the mot you actually want to use for something... this will limit the current draw to the max the second mot can draw normally.

Re: SMPS Flyback question
brandon3055, Thu Aug 16 2012, 10:36PM

Alternatively I have found that the balaced from a verry big light similar to what is used in street lights works fairly well
Or you could make a veritable inductor by removing the secondary of another MOT and winding a smaller coil of about 50-100 turns which you can apply a dc current to to saturate the core and increase current (i haven'.t Tried this but it should work quiet well)

Re: SMPS Flyback question
zippotix, Tue Aug 21 2012, 04:24PM

Destroyer, can you take a look at this ? Is this how to ballast a MOT? I don't get it, how it limits the current?

Re: SMPS Flyback question
Platinum, Tue Aug 21 2012, 05:06PM

While I did have some success with the halogen transformer setup, there isn't a way to increase current output, I've already asked the same questions, check out my threads, I've used a 250watt supply, but I used only 3 turns which lead to the death of the transformer, this isn't a way to drive a flyback, if I were you, use atleast 10 turns, flyback output will be lower, but then the transformer won't be destroyed, also these things get very hot, fast, meaning that it's not an efficient way to drive a flyback. Try building a ZVS, or half-bridge, the latter being harder, I'd go for the ZVS for it's simplicity.

Here are my thread, maybe you can learn something from them (maybe...)



Use 15 turns on the primary pull a few arcs with it, check the heat of the primary wires and also the transformer itself, and then lower if it's not hot, stick with more turns than less.

Re: SMPS Flyback question
zippotix, Tue Aug 21 2012, 05:22PM

Platinum, I already built a ZVS. I used 3 turns occasionally, and only thing that got hot was the primary, up to the point when insulation on it started to melt, lol. I rarely use it now though. Thanks for the link, I saw your thread some time ago ;). Can you look at the "pic" I posted above, and tell me if it's correct? I'm not sure I got it right.

Re: SMPS Flyback question
Platinum, Tue Aug 21 2012, 05:36PM

I'm not sure what that schematicis meant to be, But 3 turns is way too low use more. If you want more power in the ZVS, use a better more powerful supply, I use 45v near 15amps, but the voltage drops to 35~ Still alot of power. Don't forget to use a good long chicken stick.

Re: SMPS Flyback question
brandon3055, Tue Aug 21 2012, 10:11PM

Some people use secondary balaceding like shown in your pick but I would recommend balaceding the primary all you have to do is disconnect one of the power leaded from the MOT and put the primary of the second mot with its secondary shorted in series so to simplify things what you are doing is running two mots in series and shorting one and using the output of the other

Re: SMPS Flyback question
zippotix, Wed Aug 29 2012, 05:25PM

Thanks destroyer, your idea seems easier. Anyway, strange thing, I connected 2 MOCs (1uF and 0.95uF) to a MOT, and it was supposed to give big arcs (and trip my breaker). But to my suprise, the output was really low, maybe 2kV, but really small current. What the hell? Is that some sort of ballast?