Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Thu Oct 25 2007, 09:56AMHi guys,
I know most you of do not like my SSTC design. However I changed few things in the circuit (I’m using GDT) and two IGBT in parallel and my coil is becoming a small monster…There is no feedback in the circuit - but I'm working on it
It is also funny that simple playing with the pulse width increased the spark lenght a lot. Generally shorter pulses are much better...
The scheme is here:
Here is the picture (sorry the day light) and I’ll post also a movie later…
BTW: Power consumption is horrible - 600W! It is still not a master of efficiency :)
few more pics...
BTW the lamp in the second picture is powered from the coil. I had to remove the bulb (incadescent) to make realy dark photos...
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Sulaiman, Thu Oct 25 2007, 10:00PM
That's quite nice,
how many watts do you think your TC is using?
Sulaiman, Thu Oct 25 2007, 10:00PM
That's quite nice,
how many watts do you think your TC is using?
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Thu Oct 25 2007, 11:13PM
My most pessimistic guess is that I dissipate approx. 100W in the transistors and TVS. However my driving pulses are still not ideal (maybe bad ferrite in the GDT) so I think it can be still litle bit improved.
BTW during experimenting with this coil I havn't destroy a single transistor yet with using one of the cheapest IGBT without internal diode (BUP 314).We can measure the efficinecy also by this fact :).
During the weekend I will increase the power to 1000W - so I'll send more pictures...
I also made small change regarding the TVS bath - I rinsed them isntead into the cooking oil into break fluid. Break fluid is better heat conductor and moreover, it is partial electric conductor (total resistance of the TVS bath is around 100K Ohms). I don't know why but it seems that this leads to decrease in the heating of the TVS and also the sparks seems bigger...
Break fluid is also great medium for making non-inductive heat resistant resistors (I've made few of them some time ago).
one more night shot with bigger top load...
Mates, Thu Oct 25 2007, 11:13PM
Sulaiman wrote ...
That's quite nice,
how many watts do you think your TC is using?
That's quite nice,
how many watts do you think your TC is using?
My most pessimistic guess is that I dissipate approx. 100W in the transistors and TVS. However my driving pulses are still not ideal (maybe bad ferrite in the GDT) so I think it can be still litle bit improved.
BTW during experimenting with this coil I havn't destroy a single transistor yet with using one of the cheapest IGBT without internal diode (BUP 314).We can measure the efficinecy also by this fact :).
During the weekend I will increase the power to 1000W - so I'll send more pictures...
I also made small change regarding the TVS bath - I rinsed them isntead into the cooking oil into break fluid. Break fluid is better heat conductor and moreover, it is partial electric conductor (total resistance of the TVS bath is around 100K Ohms). I don't know why but it seems that this leads to decrease in the heating of the TVS and also the sparks seems bigger...
Break fluid is also great medium for making non-inductive heat resistant resistors (I've made few of them some time ago).
one more night shot with bigger top load...
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
101111, Thu Oct 25 2007, 11:55PM
Very nice, what type of MMC do you use ? and what circuit ?
101111, Thu Oct 25 2007, 11:55PM
Very nice, what type of MMC do you use ? and what circuit ?
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Fri Oct 26 2007, 12:02AM
Just check my previous thread: SSTC probably the simplest design
I'm actaully stupid I started this new thread I shouold have continue the older one - sorry...
Mates, Fri Oct 26 2007, 12:02AM
Hamachi wrote ...
Very nice, what type of MMC do you use ? and what circuit ?
Very nice, what type of MMC do you use ? and what circuit ?
Just check my previous thread: SSTC probably the simplest design
I'm actaully stupid I started this new thread I shouold have continue the older one - sorry...
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Dr. Dark Current, Fri Oct 26 2007, 07:53AM
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
Dr. Dark Current, Fri Oct 26 2007, 07:53AM
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Sat Oct 27 2007, 10:09AM
Ok, I checked it and in case I understand your hint - for me this would mean just to add foil cap in paralel with the transistor (my guess is around 100nF to meet the resonace ). The question is wheter there is any point of driving the transitor in the resonant freq anymore.
So I tested it and it works great... I took me a while to tune the cap (and is still not perfect - my primary is not naked so I can not tune by moving the contact). Anyway, the sparks are bigger and the heat dissipation decreased! I could even decrease the amount of TVS to 5 doublets. All the changes are in the scheme (in red) and I'm adding also a picture of the new sparks...:)
I just noticed that the scheme picture is too small for reading so here is a full size version:
and one more picture here:
Mod Edit: double posts in thread fixed as requested by Mates
Mates, Sat Oct 27 2007, 10:09AM
jmartis wrote ...
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
Ok, I checked it and in case I understand your hint - for me this would mean just to add foil cap in paralel with the transistor (my guess is around 100nF to meet the resonace ). The question is wheter there is any point of driving the transitor in the resonant freq anymore.
jmartis wrote ...
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
Nice sparks from one transistor. I would suggest you to read on Class E SSTC, you'll decrease the transistor heating and make bigger sparks (though I don't know if the primary voltage wouldn't go too high)
So I tested it and it works great... I took me a while to tune the cap (and is still not perfect - my primary is not naked so I can not tune by moving the contact). Anyway, the sparks are bigger and the heat dissipation decreased! I could even decrease the amount of TVS to 5 doublets. All the changes are in the scheme (in red) and I'm adding also a picture of the new sparks...:)
I just noticed that the scheme picture is too small for reading so here is a full size version:
and one more picture here:
Mod Edit: double posts in thread fixed as requested by Mates
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Mon Oct 29 2007, 10:03PM
I hope is not double posting, because I increased the power consuption to 1KW and played with the value of the cap which is in paralel to the transistor. I managed the longest sparks yet and I will buy more motor caps to reach the limit (I plan to sacrifice either the transitors or the TVS)...
Here are the latest sparks pictures... The longest is almost 50cm long.
Mates, Mon Oct 29 2007, 10:03PM
I hope is not double posting, because I increased the power consuption to 1KW and played with the value of the cap which is in paralel to the transistor. I managed the longest sparks yet and I will buy more motor caps to reach the limit (I plan to sacrifice either the transitors or the TVS)...
Here are the latest sparks pictures... The longest is almost 50cm long.
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Sun Nov 04 2007, 09:00PM
I decreased the power consuption to 200W and played with the tunning of the resonance cap (the red one in the scheme). I have only 4 TVS (2x2 in series) and one transistor and after 10 minutes of working the transistor cooler is only litle bit warm (But it is massive piece of aluminiumn on the other hand :) ) and the oil bath for the TVS keeps RT... So finally I feel I'm loosing only litle bit of the energy in dissipation...
I also added one more diode into the circuit - it is just a simple 8A bridge connected as 16A diode with double voltage. I have the feeling this can be helpful for the TVS, because in case I'm out of tune they are getting very hot (I actually destroyed few of them while I was tunning my 1000W setting).
The scheme and some new pics of 200W in action
Mates, Sun Nov 04 2007, 09:00PM
I decreased the power consuption to 200W and played with the tunning of the resonance cap (the red one in the scheme). I have only 4 TVS (2x2 in series) and one transistor and after 10 minutes of working the transistor cooler is only litle bit warm (But it is massive piece of aluminiumn on the other hand :) ) and the oil bath for the TVS keeps RT... So finally I feel I'm loosing only litle bit of the energy in dissipation...
I also added one more diode into the circuit - it is just a simple 8A bridge connected as 16A diode with double voltage. I have the feeling this can be helpful for the TVS, because in case I'm out of tune they are getting very hot (I actually destroyed few of them while I was tunning my 1000W setting).
The scheme and some new pics of 200W in action
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Wolfram, Sun Nov 04 2007, 09:27PM
Not bad at all! I might have to give this a try myself. What's the maximum sparklength at 200W input power?
Anders M.
Wolfram, Sun Nov 04 2007, 09:27PM
Not bad at all! I might have to give this a try myself. What's the maximum sparklength at 200W input power?
Anders M.
Re: Ultra simple single transistor SSTC - 18" sparks (over 45cm)
Mates, Sun Nov 04 2007, 09:48PM
I've just measured it for you - it is over 20cm (8").
It would be nice to solve some kind of a simple feedback for this circuit...My skills are very limited regarding this...
Mates, Sun Nov 04 2007, 09:48PM
Anders M. wrote ...
What's the maximum sparklength at 200W input power?
Anders M.
What's the maximum sparklength at 200W input power?
Anders M.
I've just measured it for you - it is over 20cm (8").
It would be nice to solve some kind of a simple feedback for this circuit...My skills are very limited regarding this...
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