Electrical igniter for gas engines A keystone to understanding by Magluvin

[Magluvin]

One more thing, in case any of you try my setup. It seems the bigger, as in power capability, transformer, the better the output. Remember, the battery only sees the large inductor as a load, so no matter how big the transformer, the input current will stay the same, as long as the freq of switching and the large inductor remain the same. If the large inductor is say 100ohm, the transformer coil in series is negligible in input variances.

So the large inductor gets the cap up to a couple hundred volts that is pulsed to the transformer in dc impulses. So the output on the transformer can be a couple thousand volts, as in sparks will jump a mm or 2 on the 120v side output. But the phone chargers we have today use ac/dc converters that one of the first components the 120v wall current sees is a bridge then a 450v cap. Well that cap takes that couple thousand volts can sorts it out to a working voltage, and not enough yet as the charger cuts out quite a bit, also due to unstable running at a wanted freq. I find above 60hz, up to maybe 200hz max for different transformers. My largest one is from an older ups un-interuptable power supply. Its heavy and the "normal" secondaries(12 side) is .2ohm vs a smaller on from a .5a 12v plug in supply, the secondary is 17ohm, yet the input current will remain the same with either transformer in the igniter circuit. There will be some change as you change caps for different transformers and the difference in transformer circuit primary depending on size.

Neat stuff.  And the experience is good.


Mags

[delboy]

Hey Mags

I told you it will be good experience.
It would be better if the switch is one with 2 brushes and roller with conducting and isolation parts rottating high speed. That would solve regulation problem as we could regulate speed of DC motor running roller.
And you could use another secondary from some transformator as large inductor. Problem here is regulation and hiting the resonance. If you could measure inductivity of your large inductor and it's resistance then by taking value of capacity you can calculate max Q factor in resonance Q=(1/R)*(sqrt(L/C))
To measure inductivity use U/I method, put your large inductivity in series with bulb let say 100W just to protect it from current oveload, and measure current and drop voltage on it. When you get this you can calculate impedance Z=U/I and you have measured resistance R, meaning you can calculate inductivity as L=(sqrt(Z^2-R^2))/(2*pi*f)
When you know value of L for example L=0,5H then put appropriate capacity let say 4,7 uF to get resonant frequency on 103Hz.
Why is the problem regulation???
Because it is resonant circuit. You have bandwidth! If you calculated Q factor for example Q=100 and you are expecting resonance for example on 100Hz that means my bandwidth is only ∆f=f/Q =1Hz meaning you must be inside this bandwidth 100±1 Hz if you want at least half of available power! That's why relay are bad , they are not used for fast switching.

[forest]

I think we should analyse Tito first schematic, maybe we could recreate it.I have the feeling that I did something similar in the past but didn't knew how to extract power from it.
I would start with dead battery - some with internal shortcircuit but able to be charged to 12V. I have such one and it behaves like a giant capacitor. You can charge it really fast (in few minutes) or just 12 hours with 4amp - no matter because the behaviour is the same : it can develop lots of amps for a very short period of time then it become dead completely.For example using 55W bulb it can shine it to full brightness for a 5-10 seconds then it become dimmer and dimmer and finally after a minute it goes down to barely red filament. After disconnecting load it tends to rise voltage up to 10 v and after a few minutes you can again light 55W bulb but not to full brightness.
So my first advice is to use such dead battery as in Tito schematic - it may work like a capacitor.
Do you realized that relay is a micro Tesla coil ?!!!

[Magluvin]

Hey Delboy and Forest

Yes it is a good thing to experiment with this. I kike the fact that there isnt extremely high voltage and it is simple to try it out. The rotating switch will be the next step, I see where if we dont have consistent switching, the magic can be missed.
I have a 12v battery that sits at about 6v but seems to rise really quick to a charge of 13v, bur even after hours, the charge fades quich when the charger is removed. Its just a bad battery with sulfated plates. So there is little area for the charge to build, and it acts like a small battery.

Mags

[forest]

delboy,Tito and Mag and others  I have two questions , they can sound strange and offtopic but are important trust me.
I ask here because I'm not experienced in physics or electronics.
First question is about capacitor. Let's see : if I take 0,1uF/400V capacitor good for high frequency circuits polyester type and join both terminals with a fast diode for 400V what I obtain ? Is that now polarized capacitor like electrolytic one  and can be charged only using DC and used only in DC related circuits ?
Second question is about core saturation.I hope there are topics in electronic knowledge related to core saturation which I can use to compute properties of current in coil and time required to saturate given core.Help me please find those information and equations.