Simple DR?SSTC
Mates, Sun Nov 11 2007, 12:43AMHi guys,
I’m enough of a single transistor and decided to make my first half-bridge. It is based on two BUP314 IGBT and TL494 driver (no feedback). As a current limit is used the circuit by itself involving rolled motor caps (total 150uF). Sparks are nice and almost 50cm long, the transistors heat dissipation is not critical – but I decided for active cooling anyway…
Comments and questions welcomed…
Re: Simple DR?SSTC
Shaun, Sun Nov 11 2007, 12:59AM
So its a DRSSTC now, awesome! Since it is, you need some thicker primary wire, and maybe a bigger resonant cap. It will help a lot with spark length.
Shaun, Sun Nov 11 2007, 12:59AM
So its a DRSSTC now, awesome! Since it is, you need some thicker primary wire, and maybe a bigger resonant cap. It will help a lot with spark length.
Re: Simple DR?SSTC
Colin 99, Sun Nov 11 2007, 05:35AM
I'd say it's an SSTC. There is no interupter. If you primary cap was at resonance you'd blow a fuse or circuit breaker. Also you DC cap to supply power to your IGBT's is was too small.
Shaun
Colin 99, Sun Nov 11 2007, 05:35AM
I'd say it's an SSTC. There is no interupter. If you primary cap was at resonance you'd blow a fuse or circuit breaker. Also you DC cap to supply power to your IGBT's is was too small.
Shaun
Re: Simple DR?SSTC
Mates, Sun Nov 11 2007, 09:32AM
This circuit does not need an interrupter and neither a fuse because it is self limiting in the amount of power delivered to the transistors.(you can short-circuit the + and - and nothing happens, you would only hear gentle 50Hz noise). I do not want to argue whether it is DRSSTC or just SSTC – I do not exactly now how the DR is defined. However my coil has resonant cap with the primary which is loaded by transistors driven also in resonanace freq. thus I call double resonant…
Mates, Sun Nov 11 2007, 09:32AM
Colin 99 wrote ...
I'd say it's an SSTC. There is no interupter. If you primary cap was at resonance you'd blow a fuse or circuit breaker. Also you DC cap to supply power to your IGBT's is was too small.
Shaun
I'd say it's an SSTC. There is no interupter. If you primary cap was at resonance you'd blow a fuse or circuit breaker. Also you DC cap to supply power to your IGBT's is was too small.
Shaun
This circuit does not need an interrupter and neither a fuse because it is self limiting in the amount of power delivered to the transistors.(you can short-circuit the + and - and nothing happens, you would only hear gentle 50Hz noise). I do not want to argue whether it is DRSSTC or just SSTC – I do not exactly now how the DR is defined. However my coil has resonant cap with the primary which is loaded by transistors driven also in resonanace freq. thus I call double resonant…
Re: Simple DR?SSTC
Electroholic, Sun Nov 11 2007, 08:11PM
I really don't see how it is self limiting other than that the diodes will blow when you short it, or drive it at resonance.
please explain
Electroholic, Sun Nov 11 2007, 08:11PM
I really don't see how it is self limiting other than that the diodes will blow when you short it, or drive it at resonance.
please explain
Re: Simple DR?SSTC
teslaguy, Sun Nov 11 2007, 08:28PM
i think im going to try to make this on 110v with some old h324ad 40n60a 4d igbt's...ill tell you how that pans out.
teslaguy, Sun Nov 11 2007, 08:28PM
i think im going to try to make this on 110v with some old h324ad 40n60a 4d igbt's...ill tell you how that pans out.
Re: Simple DR?SSTC
Dr. Dark Current, Sun Nov 11 2007, 09:19PM
However DRSSTC's can not be run in CW even with current/limited supply, because you would get nearly no output from the coil.
BTW the half bridge is begging for some decoupling caps 8-o
Dr. Dark Current, Sun Nov 11 2007, 09:19PM
Electroholic wrote ...
I really don't see how it is self limiting other than that the diodes will blow when you short it, or drive it at resonance.
please explain
From what I can see it's a sort of halfwave doubler, so the short-circuit current is defined by the size of the cap. I really don't see how it is self limiting other than that the diodes will blow when you short it, or drive it at resonance.
please explain
However DRSSTC's can not be run in CW even with current/limited supply, because you would get nearly no output from the coil.
BTW the half bridge is begging for some decoupling caps 8-o
Re: Simple DR?SSTC
Ken M., Sun Nov 11 2007, 10:05PM
Also if I'm not mistaken a DRSSTC is defined as having two (2) feedback circuits to allow the primary to resonate causing more power to be applied to the secondary which would also resonate but it has to resonate to work anyways. As far As I can tell its just a SSTC with a voltage doubler and IGBT's instead of Fets.
Ken M., Sun Nov 11 2007, 10:05PM
Also if I'm not mistaken a DRSSTC is defined as having two (2) feedback circuits to allow the primary to resonate causing more power to be applied to the secondary which would also resonate but it has to resonate to work anyways. As far As I can tell its just a SSTC with a voltage doubler and IGBT's instead of Fets.
Re: Simple DR?SSTC
Coronafix, Mon Nov 12 2007, 05:12AM
No, a DRSSTC has two resonant circuits. ie an inductor and capacitance in the tank circuit.
A SSTC just drives the the primary at the resonant frequency, whereas a DRSSTC has the tank
oscillating at a frequency and the IGBTs acting as the spark gap and firing at a presettable BPS.
Coronafix, Mon Nov 12 2007, 05:12AM
No, a DRSSTC has two resonant circuits. ie an inductor and capacitance in the tank circuit.
A SSTC just drives the the primary at the resonant frequency, whereas a DRSSTC has the tank
oscillating at a frequency and the IGBTs acting as the spark gap and firing at a presettable BPS.
Re: Simple DR?SSTC
Ken M., Mon Nov 12 2007, 01:29PM
I hate trying to explain or understand the differences between DR and regular SSTCs, I usually get them wrong, eitehr way someone with more knowledge explained it. (And I tryed!)
Ken M., Mon Nov 12 2007, 01:29PM
I hate trying to explain or understand the differences between DR and regular SSTCs, I usually get them wrong, eitehr way someone with more knowledge explained it. (And I tryed!)Re: Simple DR?SSTC
Dr. Dark Current, Mon Nov 12 2007, 03:02PM
Dr. Dark Current, Mon Nov 12 2007, 03:02PM
Goldsphere wrote ...
No, a DRSSTC has two resonant circuits. ie an inductor and capacitance in the tank circuit.
A SSTC just drives the the primary at the resonant frequency, whereas a DRSSTC has the tank
oscillating at a frequency and the IGBTs acting as the spark gap and firing at a presettable BPS.
What you are describing is an OLTC (off line tesla coil). In DRSSTC the FETs still switch at the resonant frequency.No, a DRSSTC has two resonant circuits. ie an inductor and capacitance in the tank circuit.
A SSTC just drives the the primary at the resonant frequency, whereas a DRSSTC has the tank
oscillating at a frequency and the IGBTs acting as the spark gap and firing at a presettable BPS.
Re: Simple DR?SSTC
Mates, Mon Nov 12 2007, 05:27PM
Yesteday I tried to pull a plasma from the top load and during this process both transistors died
(WHY?!) It looks the design is too simple and after this painfull double death I can not recommend the construction based on the scheme I posted. My problem is I'm not in my country and it is PITA to get parts for making a proper DRSSTC. Also my old 30Kg two channel russian osciloscope is at home which means 1200 Km - that's why I'm trying this crazy approaches.
Now I have only one last IGBT which I need for my MARX HV supply so that means enough of TC-fun for some time.
BTW my Marx will be soon in the project section - I made some interesting HV underwatter experiments I need to discuss.
Cheers
Mates, Mon Nov 12 2007, 05:27PM
Yesteday I tried to pull a plasma from the top load and during this process both transistors died
(WHY?!) It looks the design is too simple and after this painfull double death I can not recommend the construction based on the scheme I posted. My problem is I'm not in my country and it is PITA to get parts for making a proper DRSSTC. Also my old 30Kg two channel russian osciloscope is at home which means 1200 Km - that's why I'm trying this crazy approaches. Now I have only one last IGBT which I need for my MARX HV supply so that means enough of TC-fun for some time.
BTW my Marx will be soon in the project section - I made some interesting HV underwatter experiments I need to discuss.
Cheers
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