SpudFiles

Uploaded the second video again as youtube seems to have are it:

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Fnord wrote:Holy crap JSR you actually got a flyback working on your first try? That is indeed a win.

Well, I did have a very supportive forum that held my hand along the way

Be careful with the input voltage. My first try worked fine with 9 volts but fried quickly with 12.

What fried exactly? I have a pretty big heatsink on the transistor, and now included a 12V fan in the circuit in parallel, should be fine right, or is it a question of voltage, not current?

Here's a beefed up version that may help out if your current setup proves ineffective. You can probably fine the 25v capacitor in your junk somewhere. Exact valves aren't critical. The diode should be an ultra-fast recovery type and the 200v capacitor should be a high-quailty foil-film cap(they usually look like plastic boxes).

Interesting... though would I be stressing a potentially delicate system out?

You may want to buy some transistors eventually, in this case I found a 2n3773 works well.

This is really a "temporary" setup for static testing, I think I'll invest in the smaller commercial ignitors mentioned in this thread for actual installation in launchers, assuming the power increase of higher mixes makes it worthwhile.

You can burn the insulation on the windings if you get them too hot = short = useless coil. I've already ruined one winding on my flyback.

Is that diode and cap acting as a voltage doubler for the primary then?

Incidentally, if you're after the highest possible voltage from a commercial igniter you might want to go for one with dual ignition coils.

This one is a 9V powered one which has two 30KV coils (seems to be a standard voltage claim for ignitors) in it, being demoed with one coil at maximum reliable sparking distance, think it was about 10mm here:

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Then both coils wired in series which allows a notably longer spark, full 20mm in fact:

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The reason the spark rate is the same is because both coils are being fed pulses irregardless of whether you're using one or both coils.

I hate to be that dude who posts the same stuff over and over again... but there are ready made modules like that

For example this is for gas stoves/ovens http://www.miflex.com.pl/pol/generatory/W09-2A.pdf

POLAND_SPUD wrote:I hate to be that dude who posts the same stuff over and over again.

So how about posting a cheap and convenient souce for them

try ebay or any local place selling spare parts for home appliances

What fried exactly?

It started arcing internally; the HV coming out of secondary decided there was less resistance in the wire insulation than the air gap I was trying to make it jump.

If you're going to kill the transistor(from heat build-up), you'll know. Most of them will get burning hot before they die. There's no real way to know if you're putting too much voltage through it unless you have the specs sheet.

though would I be stressing a potentially delicate system out?

In the long run, yes, but every setup I've seen like this survived just fine, the exception being people who like to run them continuously for minutes at a time.

Is that diode and cap acting as a voltage doubler for the primary then?

To be honest I'm not sure. I think it's designed to catch the reverse voltage spike across the transistor and re-use it later. I took me long enough just to figure out how the basic driver works!


___

I have to say I really like the idea of dumping a small cap into a glow plug ignitor. Originally glowplugs didn't sound like an option for hybrid use, as high mixes would lead to slow warm-up time, and coupled with a sudden 4000 degree temperature shift would probably burn out the wire quite quickly. But a cap allows you to shut off the circuit as soon as it ignites, reducing the chance of damage.

Cheers so overheating isn't really an issue for ignition purposes, and adding a fan would be overkill, right?

I took the circuit apart to put it back together in a (very) slightly neater fashion, and in the process broke off the transistor's "third leg" (:roll:) - fecksocks, so I tried with the 2527AX (bottom row third from right) at it worked anyway I plan on fitting it in a power supply case, I'll post pictures when it's done.

I tried the mini-hybrid at 20x and it worked, WIN!!! Upped it to 25x and fail, it seems the burst disk holder objected to having to hold back the 350 psi pre-ignition pressure. I have a lot of experimentation to do over the weekend especially with the mini and micro hybrids. With my 3/4" prototypes it's abundantly clear that 9-12x is already at the limit for indoor urban testing in terms of power and noise, so I won't be going any higher with those.

I have to say I really like the idea of dumping a small cap into a glow plug ignitor. Originally glowplugs didn't sound like an option for hybrid use, as high mixes would lead to slow warm-up time, and coupled with a sudden 4000 degree temperature shift would probably burn out the wire quite quickly. But a cap allows you to shut off the circuit as soon as it ignites, reducing the chance of damage.

Anything that would help me avoid a spark gap would be a huge benefit in terms of avoiding the insulation and external arc issue, I'm thinking small cartridges.

From my limited knowledge (which might be completely wrong) I see the following options:

- charging a cap from a normal supply and discharging it directly, giving essentially a short burst of what the power supply would have provided.

- charging a cap to high voltage through a transformer then discharging it normally

- charging a cap normally then discharging it through a transformer

- charging and discharging through a transformer

I prefer the first one as it's the simplest and the least likely to fuse the hot wire, but it might not have enough "oomph" for a hybrid mix.

The second option seems to make more sense after that, opinions, ideas? I'm open to doing some practical R&D

http://www.miflex.com.pl/pol/generatory/W09-2A.pdf

ordered... I should get it this week

POLAND_SPUD wrote:ordered... I should get it this week

Direct from the manufacturer?

nope... they replied that they don't handle small orders, but they suggested emailing one of the wholesale stores that has their products...

I paid 7.5 euro total, including shipping... we'll see if it's any good

POLAND_SPUD wrote:I paid 7.5 euro total, including shipping... we'll see if it's any good

Bleedin' heck, that's a good price! Let us know how it turns out

Win!

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Now to figure out what part in the tv this flyback came from is bad. ???

Nice! By the way, here's how I "neatened" my setup - twisted wire and Araldite "soldering" then I chucked it in a small box which originally contained a Russian mug

nice...
ohh btw I think I know what fried my spark generator... uhmm yeah I know I used several times higher voltage and amperage than I should but IIRC it stopped working right after the output arced into the part of the case that houses electronics

lol you might say - so what? well, apparently it isn't the best idea to separate the two leads with a dielectric - at least that's what one guy selling HV circuits told me a few days ago

So maybe the generator I got could have survived that abuse if I hadn't have separated the two leads

JSR what is your power source?