Fwd: [TCML] Safety gap firing - (JAVATC Questions)

[otmaskin5@xxxxxxx]

Thank you to those who repsonded to my post.? Regarding a couple of the suggestions and additional questions I received:

Bart - my spark gap = RQ style, 10 pipes - 1" diameter- 4" long, each gap 0.03" X 9 = 0.27.? My NST easily arcs accross all segments, might go longer, but I only built 9 gaps.

The safety is part of a Terry filter & is similar to yours (3?electrodes / center one grounded), the electrodes are small cabinet-type door knobs - relatively flat surface, but slightly curved (convex).? Right now, each gap is set at 0.15" for a total safety gap with of 0.3".? Maybe I've just been too conservative at 0.3"?

DC - I actually have a 21 turn primary.? It's tuned (painstakingly) to 14.25 turns.? JAVATC calculated tuning at 14.054, kind of close to what I arrived at.? My concern with your suggestion about the need for no safety gap is that, if there's an underlying problem, and I don't address that & just rely on MOVs, I'll just wear out?the MOVs? That said, I would be still be interested in your Terry filter plans.? Thank you for the offer.

Matt D - I relate to your comments?about trying "what ifs."? My coiling preference is decidedly to experiment, rather than just build a coil based on a precise cookie cutter set of plans.? That's why my primary has 21 turns for flexibility & my basement is full of various home-made toroids.? 

I designed my coil - for better or worse - from ideas I got from many of your sites, reading electronics books, other sources - rather than a single set of plans.? I've been able to exceed the Freau factor and worked through a lot of problems along the way, but this safety gap thing is so far the only?one I've been stuck on.

Here's my game plan:
1. First, barrow a scope & verify my tuning with it.
2. Then, gradually open the gaps as Bart recommends, monitoring along the way.
3. If that doesn't work, threaten the @#$%! coil with a sledgehammer.

More to follow...Thanks, Dennis




-----Original Message-----
From: otmaskin5@xxxxxxx
To: tesla@xxxxxxxxxx
Sent: Sun, 20 Apr 2008 7:59 pm
Subject: Re: [TCML] Safety gap firing - (JAVATC Questions)



This has been the most frustrating part of my coiling experience.? When running 
the coil, my safety gap fires anywhere between frequently and constantly.? I 
have tuned, re-tuned, re-re-tuned ad-infinitum, raised & lowered the toroid, 
raised & lowered the secondary, rebuilt components including the safety gap, the 
MMC, spark gap & tried several suggestions from this group.? In well over 2 
years of coiling, I have not been able to solve this problem

I have my static spark gap closed down so far, that I'm surprised I even get any 
sparks at all (although somehow, I am getting?pretty decent sparks).? But I know 
I'm seriously limiting performance.? Right now, I'm down to a 0.12" spark gap 
with a 15/60 NST - & STILL get some safety gap firing.? The NST connected only 
to the spark gap easily fires all nine segments for 0.27" total gap every time I 
try it.? I know a lot of guys are running much wider than I am.? Seems like from 
everything I read from other coilers, they are at 0.25" spark gaps or more.? The 
Dr. sent me plans for a 12000 NST coil with a 0.25" gap spec.? I'm not looking 
to go crazy overextending my components with an improperly wide spark gap, but 
my current 0.12" seems ridiculously low.

I am going to try resetting the safety gap as Bart suggests, although what he 
describes seem pretty close to what I did.? I'm also going to find someone with 
a scope & signal generator locally to verify tuning.? But beyond that I'm 
stumped.? I'll let you know?what happens.? Thanks for listening.? Dennis 
Hopkinton MA


-----Original Message-----
From: bartb <bartb@xxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Sun, 20 Apr 2008 6:17 pm
Subject: Re: [TCML] JAVATC Questions


Hi Dennis,?
?
Yes, 1/8" total gap. This is a safety gap and your main gap is something else, 
right? The "safety" gap you will have to experiment with even after it's on the 
system. The main gap should be set to just fire with the transformer. The safety 
gap should be set to not fire except if the main gap has a problem. How often 
the safety gap fires will depend on the regularity of the main gap. If the 
safety gap fires too often, it can heat up and then start firing more and more 
often as the electrodes heat and as the air around the safety gap becomes more 
ionized.?
?
Take care,?
Bart?
?

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