[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Terry's DRSSTC - First light ;-))
Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
At 06:50 PM 3/15/2005, you wrote:
I presume you are using some type of grounded strike rail?
Yes. I put on a nice new rail "since" I blew the last IGBTs:
But ya know how sparks sometimes just don't behave...
The darn streamer might have curled in around under the rail... That is
what I "thought" happened. But Erik's face was a few feet away, and he
say's it hit the main DRSSTC control box...
We make up 3 stands that terminate on top with a 1/2 dia metal cabinet knob.
The stands have a 5 x 5 inch x 1/4 inch thick base. Each vertical brass rod
is adjustable from 12 inches up to 3 ft.
I was thinking "barbed wire" might make a better strike rail "coating"...
The three are joined together with standard "bananna" plugs and receptacles
for fast setup.
Might be nice to have the H-bridge on banana jacks for easy
replacement.... But best not to blow the dumb thing up in the first place
per my other post on protection...
We place them 3-4" away from the edge of the upper base support --- just
outside of the primary. We made the vertical brass piece adjustable with a
small hose clamp. This allows vertical adjustment for different coils such
that the small terminal ball is approx 3-4 inches above the primary coil and
3-4" outside of it. In essence, a portable strike rail!
Would it not be better to have "points" like a lighting rod.... The balls
are safer however if you fall onto one...
It's very easy to set up and makes the mounting of a fixed ring on the pri a
thing of the past. Allows placement around different coils as you build
The "box" has a heavy epoxy/plastic coating. The six panels are not well
grounded since the screws do not penetrate the coating. I need to mod a
mill bit or something to chew through it at the screw holes... If the
streamer did hit the box, the electronics may have gotten a "glitch". I
"thought" it was out of range... But the electronics were not damaged
"permanently" or anything...
It was at Bill Lemieux's house in Denver, so I did not bring along the
extra bulk of the video camera to "catch" the event...
The main ground is attached to the main ref ground --- same one as the
bottom of the sec coil.
> >Could a DC blocking capacitor be added in series with the ground
> >to the tesla coil secondary? In the event of a strike to the primary the
> >bus caps cannot then discharge through the IGBT into the ground via the
> >secondary. Just an idea, maybe there is greater problems than this to
> >about or this just adds further problems.
> I have been thinking real hard on this %:-)
> I blew two more IGBTs Sunday when a streamer either hit the primary again
> or the DRSSTCs case at 41 inches!!! They guy closest said it hit the case
> where others though the primary got hit (no cam this time). Happily, it
> just blows pairs of IGBTs which is not bad to fix at all!
> A DC block all by itself still lets bad RF through, but simply adding an
> inductor forms a bandpass filter that may indeed do the trick!! I wrote
> the details here:
> Thanks for the starting idea!!