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Re: [TCML] Fixing secondary strikes Re: Bad strike to a 12 inch traditional coil (somewhat terminal)



The strike rail must be open. If it is closed, it is a one turn short circuit. In doing this, it will dampen the primary magnetic field which in turn will reduce the output of the secondary.
The shorted turn will take the energy away from the primary,
This is like an induction heater where a few turn coil will induce a large current in the object to be heated, IE a 1 turn coil. Lots of current will flow thru the shorted turn. It will also force a large current draw thru the primary but typically in a spark gap coil, this cannot happen but it will try and draw more current. A shorted strike rail WILL reduce the output of you coil and it might get hot depending on the amount of power you have in your primary circuit. A pole pig transformer set will probably heat the rail for example but a NST powered one probably will not.

A radio transmitter is not shorted or dampened, the energy is free to radiate from the antenna. This is why receivers can work. It you took a loop or a few turns of heavy wire and shorted them thru a lightbulb and brought it near the radio antenna, you would see the light start to glow and also the effective range of the transmitter would diminish as its energy is now being absorbed by the coil and lamp.


At 01:06 PM 08/07/2018, you wrote:
Gentlemen permit me a follpw up question.
I understand that the heating of a closed loop rail is absorbing energy.
But is the energy that which would other wise be going into the primary
such that the power into the primary is being reduced?
This may be a false example but a radio transmitter transmits the same
energy regardless of how many receivers are operating. The energy received
by one does not affect that of other receivers
Teddy

On Jul 8, 2018 12:00 PM, "phil" <pip@xxxxxxxxxxx> wrote:

> Teddy.
> Your question makes a good point, and the explanation is as Garry states;
> I was simply drawing attention to the fact that the coil's owner had
> remembered to place a gap in the ring. I'll add something in the
> description.
>
> PS: I'm not aware of situations where you would have a closed loop (maybe
> others are?)
>
> Phil T
>
>
> On 08/07/18 00:45, Tedd Dillard wrote:
>
>> Gentlemen the reasons for my question are;
>> 1. I am new at this so am trying to understand how these things work. They
>> are obviously complicated so getting into details is important.
>> 2. In reading past post I remember some discussion on strike rings that
>> included some reference to open and closed loop rings but I was not clear
>> on the issue.
>> 3. In the video of the damage to the secondary one of the captions
>> indicated an open loop strike ring so I wondered if there was any
>> significance to specifying that it was open loop. If no one runs closed
>> loop why say it was open?
>> Teddy
>>
>> On Jul 6, 2018 5:22 PM, "Steve White" <steve.white1@xxxxxxxxx> wrote:
>>
>> If it is heating then it is absorbing energy. Heat takes energy to
>>> generate. A closed loop that is grounded would be just as effective as an
>>> open loop that is grounded but why would you even want to consider that
>>> unless this is just casual interest? It is simple enough to cut a gap in
>>> the ring.
>>>
>>> Steve
>>>
>>> ----- Original Message -----
>>> From: "Tedd Dillard" <tedd.dillard@xxxxxxxxx>
>>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>>> Sent: Friday, July 6, 2018 8:16:04 AM
>>> Subject: Re: [TCML] Fixing secondary strikes Re: Bad strike to a 12 inch
>>> traditional coil (somewhat terminal)
>>>
>>> Carl thank you for your quick response.
>>> In a closed loop does the energy going in to heating the loop detrack
>>> from
>>> the energy going into the primary or is the heating the only issue?
>>> Is there any effect on the effectiveness of the loop to protect the
>>> primary
>>> if it is an open loop.
>>> Teddy
>>>
>>> On Jul 5, 2018 10:15 PM, "Carl Noggle" <cn8@xxxxxxx> wrote:
>>>
>>> Hey--
>>>
>>> A closed loop ring will act like a single shorted turn coupled to the
>>> primary.  If it has a much bigger radius than the primary, it probably
>>> won't absorb too much power.  But is it's close, it will absorb a lot of
>>> power just heating up the ring. Putting a small gap in the ring
>>> eliminates
>>> this problem.
>>>
>>> --- Carl
>>>
>>>
>>>
>>>
>>>
>>> On 7/5/2018 5:51 PM, Tedd Dillard wrote:
>>>
>>> Gentlemen this may not be best place to ask this question but I noticed
>>>>
>>> in
>>>
>>>> the vedio that it was an open loop strike ring. Comments on the
>>>>
>>> difference
>>>
>>>> in an open loop vs closed loop strike ring please.
>>>> Teddy
>>>>
>>>> On Jul 5, 2018 1:31 PM, "Bert Hickman" <bert@xxxxxxxxxxxxxxxxxxxxx>
>>>>
>>> wrote:
>>>
>>>> Phil, Steve, and all,
>>>>
>>>>> Sorry for the damage to your secondary, Phil. The videos were excellent
>>>>> and will hopefully lead to good discussion here and effective
>>>>>
>>>> preventative
>>>
>>>> measures for higher power systems.
>>>>>
>>>>> A thick coating of 2-part epoxy or polyester may accomplish a similar
>>>>> function as PMMA tubing at significantly lower cost. When uniformly
>>>>> coated,
>>>>> errant strikes to the secondary will "splash" outward across a
>>>>>
>>>> relatively
>>>
>>>> wide area of the outer surface of the coated secondary. The coating
>>>>> dissipates spark energy by spreading it out and capacitively conducting
>>>>>
>>>> it
>>>
>>>> to the secondary without creating damaging hot spots. In practice, I've
>>>>> seen hot primary-secondary flashovers that left NO permanent or visible
>>>>> effect on thickly-coated secondaries. These would have undoubtedly
>>>>>
>>>> caused
>>>
>>>> melting and turn-turn shorts on an unprotected secondary.
>>>>>
>>>>> Your system also has a comparatively large topload OD compared to
>>>>>
>>>> primary
>>>
>>>> OD. You may want to consider adding one or two additional,
>>>>> larger-diameter,
>>>>> strike rails to spread out the E-field "footprint" of the base. These
>>>>>
>>>> will
>>>
>>>> alter the E-field between the topload and base, making it more vertical
>>>>> (in
>>>>> the space between the two) helping to reduce strikes to the secondary.
>>>>>
>>>> The
>>>
>>>> larger strike rails could be an add-on that can be removed before
>>>>> transporting the coil, and they would would require any changes to your
>>>>> existing primary winding.
>>>>>
>>>>> You may also want to consider adding a smaller toroid under the top
>>>>> toroid. By elevating the top toroid, you'll increase the outward
>>>>> "throw"
>>>>> of
>>>>> sparks while further reducing hits to the strike rail. In the latest
>>>>>
>>>> video
>>>
>>>> there were a number of hits to the strike rail that came quite close to
>>>>> flashing over to the lower half of the secondary even at 100 BPS. The
>>>>> hotter 200 BPS strikes combined with thermal rise seems to have tipped
>>>>>
>>>> the
>>>
>>>> balance, unfortunately.
>>>>>
>>>>> Good luck and best wishes,
>>>>>
>>>>> Bert
>>>>>
>>>>>
>>>>> Steve White wrote:
>>>>>
>>>>> I have also had this idea for some time. I would love for somebody to
>>>>>
>>>> try
>>>
>>>> this but even if it works I don't know if any of us could stand the
>>>>>> expense.
>>>>>>
>>>>>> Steve
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> From: "Phillip Strauss via Tesla" <tesla@xxxxxxxxxx>
>>>>>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>>>>>> Sent: Wednesday, July 4, 2018 4:02:13 PM
>>>>>> Subject: Re: [TCML] Fixing secondary strikes Re: Bad strike to a 12
>>>>>>
>>>>> inch
>>>
>>>> traditional coil (somewhat terminal)
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hello Jim,
>>>>>> Although very costly in the UK, I was considering a 350mm diam cast
>>>>>> acrylic 1 metre long tube (that's how it comes) with 5mm wall
>>>>>> thickness
>>>>>> to
>>>>>> go over my 300mm (12") diam secondary, it would cover about the first
>>>>>>
>>>>> two
>>>
>>>> thirds of the tube, a good few inches higher than the previous strikes.
>>>>>> Your comment on a dissipative tube caught my eye for that particular
>>>>>> reason
>>>>>> but I don't understand the concept of loading or that my idea would
>>>>>>
>>>>> work,
>>>
>>>> any explanation and/or prediction would be much appreciated.I'm
>>>>>> contemplating your other suggestions (which are totally novel
>>>>>> <https://maps.google.com/?q=her+suggestions+(which+are+>>>>>>
>>>>> totally+novel&entry=gmail&source=g>
>>>
>>>> to me) with
>>>>>> interest.
>>>>>> Regards,Phillip.
>>>>>>
>>>>>>
>>>>>>
>>>>>> ____________________________________________________________
>>>>>> _________________
>>>>>>
>>>>>> 14 Broad Street, Stamford, Lincs PE9 1PG
>>>>>>
>>>>>> Tel: 01780 753008
>>>>>>
>>>>>>        On Wednesday, 4 July 2018 21:26:39 BST, jimlux <
>>>>>> jimlux@xxxxxxxxxxxxx>
>>>>>> wrote:
>>>>>>       On 7/4/18 11:40 AM, David Rieben wrote:
>>>>>>
>>>>>> Hi Phil,
>>>>>>
>>>>>>> My deepest condolences for your loss. I know it's JUST a secondary
>>>>>>>
>>>>>> coil,
>>>
>>>> but as a fellow coiler, I most assuredly feel your pain. On the bright
>>>>>>> side, at least you did manage to capture some truly spectacular
>>>>>>>
>>>>>> footage
>>>
>>>> of this secondary coil mishap. I have had this happen on rare occasion
>>>>>>> with the operation of my big coil, though fortunately, none of my
>>>>>>> mishaps turned out quite that severe! Only once did I actually have
>>>>>>> to
>>>>>>> repair some damage to the side of my coil and was able to get it back
>>>>>>> into full functioning mode via the repair. Since I must operate mine
>>>>>>> outside, I did have one occasion where the wind actully "blew" one of
>>>>>>> the streamers back into the side of my secondary coil, too. Lesson
>>>>>>> learned - although refraining from outdoor operation during rainfall
>>>>>>>
>>>>>> is
>>>
>>>> an obvious good rule, non-starters in windy conditions are also well
>>>>>>> advised.
>>>>>>>
>>>>>>> I suppose this is a risk, that although may be small with a
>>>>>>> well-tuned
>>>>>>> and efficiently operating coil, is never completely absent. :^/
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> I wonder if we could figure out a way to segment a large coil
>>>>>> vertically, so if a segment gets damaged, you can just rewind that
>>>>>> segment. Just off the top of my head, I'm thinking about something
>>>>>> like
>>>>>> segments with a hundred turns or so. Could we come up with a way of
>>>>>> making the connections in a "good" way. I'm almost thinking about how
>>>>>> you using field grading rings on a Van de Graaff. You don't want a
>>>>>> complete shorted turn, but you could terminate the winding in some
>>>>>> sort
>>>>>> of flat terminal on the "mating face" of a segment. You'd stack the
>>>>>> segments, and then put some compression on it (threaded fiberglass
>>>>>>
>>>>> rod?)
>>>
>>>> The other idea that comes to mind is if there is some way to "spread"
>>>>>> the energy of the secondary strike.. Say your secondary were coated
>>>>>>
>>>>> with
>>>
>>>> a resistive (but still conductive) coating. Would that spread the
>>>>>> current density enough to prevent burning through the insulation? Or a
>>>>>> dissipative tube covering the secondary - not enough to "load" the
>>>>>> secondary, but enough to "take the hit".
>>>>>>
>>>>>> OR, what about a second helix, space wound, that extends the length of
>>>>>> the secondary, with some suitable resistive conductor, so the voltage
>>>>>> profile matches that of the secondary (so no protective helix to
>>>>>> secondary arcs), but so it doesn't enter into the resonant circuit.
>>>>>> The
>>>>>> protective helix would be mostly capacitively coupled to the
>>>>>> secondary,
>>>>>> establishing the voltage.
>>>>>>
>>>>>> What about something like a helix wound with wire, but with small gaps
>>>>>> along the length.. the gaps don't break down normally, but if a
>>>>>>
>>>>> streamer
>>>
>>>> strikes, the gaps break down and provide a conductive (but lossy) path
>>>>>> to the base.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>>
>>>>> Tesla mailing list
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>>>>>
>>>>> _______________________________________________
>>>>>
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>>>>
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>
> --
> Regards Phil www.hvtesla.com
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>
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