Re: Neutral Spike Re: [EVGRAY] Vehicle audio - Wikipedia

Body

Hi Ole,

I had not anticipated this kind of event manifesting at the TVS and a
crowbar would have worked.  However the plasma created event went right
through the protection circuits like they were not there and made its
way to the microelectronics.  It was so fast the gas tube did not even
light just a little faint line though the center like the afterglow of a
meteor.

Just in the learning stages but so far convinced for now the best way to
learn is to keep the event away from semi junctions until I understand
much more of the hows wheres and why's.


On 11/26/2018 5:21 PM, [email protected] [EVGRAY] wrote:
>  
>
> Hi Mick,
>
> TVS diodes are rated for some max power dissipation and perhaps some
> max energy too (fusing energy I^2t). If applying more energy than the
> max i^2t rating it melts. As being fast Zener diodes they clamp the
> voltage at some level while having current through them at the same
> time which means power dissipation in them. If reading EMC (EMI)
> theory several stages are needed to protect for powerful EMP
> transients. The first step is a spark gap. The spark gap is followed
> by a varistor that is followed by a TVS or Zener diode. The spark gap
> breaks down to low impedance which reflects or dissipates much of the
> energy of the signal. The varistor is a solid state spark in some
> metal grains and has the same purpose as the spark gap. the TVS or
> Zener diode stage removes the rest of the energy to protect the
> sensitive electronics. It is essential to know how the electromagnetic
> radiation is transferred between the different stages to prevent it
> from reaching the sensitive electronics. Every current loop transmits
> the energy as a very penetrating magnetic field. That magnetic energy
> has to be dissipated or reflected which can be done with electrical
> conductive materials like iron or aluminum. The field induces current
> in the screening material which requires only connecting the circuit
> inside the screen to a single point. Audio guys probably have
> experienced this when building amplifiers.
>
> A thyristor (SCR) crowbar is also a good protection. It shorts the
> pulse just like a spark gap and then blows a fuse to disconnect the
> circuit to be protected..
>
> Regards
> Ole
>
>
>
> ---In [email protected], <mkjekyll@...> wrote :
>
> Hi Norm,
>
> This paper is one of your excellent references.
>
> I would like to replicate the events through the plasma that I
> achieved as it creates a huge magnetic pulse that can be harvested but
> as you say gets to kill the solid state stuff as if the TVS diodes
> were not even there. At least the ferroresonant amplification without
> the plasma gap just cooks the TVS diodes like popcorn even though
> rated at 1000 amps with only about 2 amp 23v input, but spared the
> rest, I guess it chose at the diodes to manifest.  Oh yeah the
> ferrotranny was connected with 30 guage wire wrap wire when the 1000
> amps TVS diodes exploded from 46w and wire was fine. Have not built
> the tube circuits yet just working on the solid state grid control
> circuits first then plan to decouple with something similar to cascode
> so hopefully the superfast gate driver does not cook. 
>
> Not sure if Ole's snubber network would stop the event but have the
> feeling so since caps will suppress the rise time and kill ringing,
> but have not tried so can't say.  Seems to me the event is created
> right at the switch and the rise in voltage is like the inertia x
> acceleration before the end of a whip cracks and necessary. 
>
>
> "Why does death need time?  Death needs time for what it kills to grow
> in."
>
>
> On 11/26/2018 4:44 AM, Norman Wootan nwootan@... <mailto:nwootan@...>
> [EVGRAY] wrote:
>
>>      
>>
>>     Precisely, Bob Paddock.  Please read this document to understand
>>     that a local plasma event must occur (Arc in the gap) for the
>>     manifestation of this energy. Please read:  
>>     http://www-brs.ub.ruhr-uni-bochum.de/netahtml/HSS/Diss/TassiEmanuele/diss.pdf
>>
>>     On 11/25/2018 7:36 PM, Bob Paddock bob.paddock@...
>>     <mailto:bob.paddock@...> [EVGRAY] wrote:
>>>      
>>>
>>>     > Why not replace the relay with a switching transistor. Mechanical switches wear fast compared to
>>>     a semiconductor switch.
>>>
>>>     What if the Arc/Spark is part of the actual process in getting
>>>     more energy?
>>>
>>>     Every O/U thing I've ever though worked usually had a Plasm or
>>>     Arc/Spark.
>>>     Usually not intentionally and the designer always wanted to get
>>>     rid of it.
>>>
>