Re: Flyback Driver PCBs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dan" <pbursa-at-cfl.rr-dot-com> 


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, April 12, 2004 2:51 PM
Subject: Re: Flyback Driver PCBs


 > Original poster: "Jim Mitchell" <electrontube-at-sbcglobal-dot-net>
 >
 > Thats plenty impressive.  The problem with Aron's flyback driver is that
it
 > is limited to 15v input.  I had the same driver for a while but I was
using
 > a TL494 so I could put up to 40v into it.

No, it's not. The 555 is. Gates of  mosfets shouldn't see more than 20
volts. So TL494 -at- 40 V doesn't sound right( not to mention the fact that
TL494 doesn't sink current.)

 > If you're saying you get 4" out of a single flyback at 25v you're either
 > lying or not measuring right.

Thats what I'm saying :-) Flyback # 8-598-998, four turns of primary and I
AM measuring right

 > At 25v on the primary I can pull a 3" arc before my small flyback (which
has
 > a 1" diameter secondary) Starts to arc over internally.

get better flyback :-)

 > This is similar to Steve's flyback driver except it uses a TL494 for
better
 > control over the flyback with adjustable duty cycle.
 >
 > Once again,  a switch is a switch.  If the flyback is in resonance you'll
 > get the same sparks on any half bridge in the world if you're driving it
at
 > the same voltage

Really ? why is there so many different types of  flybacks, then ?


 > Did I mention I wasn't running my flybacks in resonance when I was pulling
 > these 3" arcs.  I just set the frequency around 30KHz and I'm sure if the
 > flyback was in resonance it would perform much better.
 >
 > Once again,  this isn't a thread to elaborate on my spark lengths.  It is
to
 > ask whether there is interest for a flyback driver PCB.

You didn't post any schematic and your description of output of the driver
sounds rather un-exiting
Regards - Vladan

 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Monday, April 12, 2004 9:53 AM
 > Subject: Re: Flyback Driver PCBs
 >
 >
 >  > Original poster: "Dan" <pbursa-at-cfl.rr-dot-com>
 >  >
 >  > two inches arc with halfbridge driver ? that's really not impresive.
With
 >  > HVguys simple flyback driver I can get 3-4 inches -at- 25V and Steve Wards
 > half
 >  > bridge driver does easy 5 inches -at- 60V.
 >  > I suggest you work on your design a bit ;-)
 >  > regards - Vladan
 >  >
 >  > ----- Original Message -----
 >  > From: "Tesla list" <tesla-at-pupman-dot-com>
 >  > To: <tesla-at-pupman-dot-com>
 >  > Sent: Monday, April 12, 2004 2:01 AM
 >  > Subject: Flyback Driver PCBs
 >  >
 >  >
 >  >  > Original poster: "Jim Mitchell" <electrontube-at-sbcglobal-dot-net>
 >  >  >
 >  >  > Hello List:
 >  >  >
 >  >  > After the recent sucsess of my SSTC boards, and my recent
 > experimentation
 >  >  > with a high powered flyback driver,  I have decied I'd like to have
 > some
 >  >  > flyback driver boards made.
 >  >  >
 >  >  > The boards would be custom 2 sided boards,  utilizing a half bridge
of
 >  >  > MOSFETs or IGBTs,  and a variable oscillator and gate drive section.
 > This
 >  >  > would work wonders as a flyback driver and as a GP high frequency
 >  > generator
 >  >  > for different experiments.
 >  >  >
 >  >  > The board would use a TL494 oscillator, that way the duty cycle and
 >  >  > frequency would be variable.
 >  >  >
 >  >  > I recently built an identical flyback driver and it works very good,
I
 > am
 >  >  > able to drive flybacks with half wave AC up to 150v or until they
start
 > to
 >  >  > break down from overvoltage (about 50v in)  and I have been able to
get
 > 2"
 >  >  > sparks from a single small flyback (a new style DC one).
 >  >  >
 >  >  > Anyway if there is any interest in these please let me know and I
will
 >  > send
 >  >  > word to have them made.  I have already designed the board and
things
 > seem
 >  >  > to look good.
 >  >  >
 >  >  > Regards - Jim Mitchell
 >  >  >
 >  >  >
 >  >
 >  >
 >
 >