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Re: oops ("Kickback" and untuned coils)



Hi Gary, Ed, all:

Gary I do see the logic of where you are thinking, and I do think you are
right sometimes, but most often it probably happens as Ed describes. In my
experience solid state death has only happened from direct strike of AC
mains and failure to unplug a device. But, the HVRF from a untuned coil
will definitely send unwitting solidstate devices into turmoil!
Interestingly, but not to surprising, my VTTC's (both filtered DC and
Pulsed up tp 24" discharge) produce very little disturbance with running
equipment (with NO rf mains filtering!). I run a small PC ethernet network,
stereo, etc. all near the coil with no adverse effects...

But a spark gap coil, and everything (important!) gets unplugged! the
tuning stage is when most people will kill there stuff. Or if you are like
me the "experimentation" stage...

Regards,

David Trimmell


At 04:30 PM 3/26/00 , you wrote:
>Original Poster: "Edward Wingate" <ewing7-at-rochester.rr-dot-com> 
>
>Tesla List wrote:
>
>> Original Poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
>>
>> Hi Ed:
>>
>> I'd like to come to a better understanding of the hazards of coiling to
>> appliances, and in particular, just what are these ill-defined demons.
>>
>> I don't understand your suggestion that an untuned coil is more prone to
>> sending HV transients over the AC line.  My current thinking has it where an
>> untuned coil is simply not efficient at transferring the primary energy to
>> the secondary, so the energy languishes in the primary tank circuit for a
>> longer than desired time, burning up energy in the gap and putting more
>> cycles and wear and tear on the tank capacitor.  But I don't see any
>> mechanism for this energy to get back to the AC mains any more-so than in a
>> tuned coil.  While the duration of each "bang" ringdown is longer, the
>> magnitude of any coupled transients would be no greater.
>>
>> Regards, Gary Lau
>> Waltham, MA USA
>>
>
>Gary,
>
>An untuned coil will produce transient voltage spikes/peaks in the primary
tank
>that are much higher in amplitude than a properly tuned coil and the
>untransfered energy does not just "languish" in the tank circuit, it finds
it's
>way back to the "mains" through the gap and transformer. Granted, a properly
>tuned coil will produce a certain amount of kickback too, hence the need
>for EMI
>filters on the line feed, but not to the extent that an untuned or badly tuned
>coil does.
>
>Harry Goldman, editor of the TCBA Newsletter once printed a letter from a
>newbie
>who wanted to know why there were SPARKS ARCING across the slots in the WALL
>OUTLETS in his home when he fired his newly constructed Tesla coil! How
long do
>you think a microwave or any other solid state device with microprocessor
>controlled displays or functions would last if plugged into those outlets?! If
>there were sparks across the outlets, what could be happening inside the
>walls!!
>
>Ed Wingate RATCB
>Brockport, NY USA
>
>