[TCML] Are safety gaps necessary?

[David Nelson]

Matt D

Pardon my ignorance but what do you mean by OH S**** episodes. Ocupational 
Health and Safety?

I feel like I have tuned it as much as I can, but I will try again. Perhaps 
I should go from 9 to 8 static series gaps of .028"

Thanks

Dave Nelson
----- Original Message ----- 
From: <mddeming at aol.com>
To: <tesla at pupman.com>
Sent: Friday, June 20, 2008 10:53 AM
Subject: Re: [TCML] Are safety gaps necessary?


> Hi David,
>
> Safety gap firing every 5-10 seconds does not necessarily mean?it is set 
> too narrow. More likely it indicates? need for tuning adjustment. I would 
> keep the strike rail until you can afford to pay for a couple of OH S**** 
> episodes and then experiment without it.
>
> Matt D.
>
>
> -----Original Message-----
> From: David Nelson <davidnelson11 at bigpond.com>
> To: Tesla Coil Mailing List <tesla at pupman.com>
> Sent: Wed, 18 Jun 2008 11:36 pm
> Subject: Re: [TCML] Are safety gaps necessary?
>
>
> Gary, Bart, all.?
> ?
> Given the advice of this list, I have set my safety gap (on a static spark 
> gap system) and when the coil is running I get occasional firing of the 
> safety gap, about 5 or 10 per minute. I was thinking this is all good and 
> it does give me a certain peace of mind. Now given this latest discussion 
> I am starting to think that I should be opening my safety gap out more. 
> BTW I have a strike rail which does get hit occasionaly and it seems that 
> the primary is very inlikely to be hit with the strike rail in place.?
> ?
> Dave Nelson?
> ----- Original Message ----- From: "Lau, Gary" <Gary.Lau at hp.com>?
> To: "Tesla Coil Mailing List" <tesla at pupman.com>?
> Sent: Wednesday, June 18, 2008 10:05 PM?
> Subject: [TCML] Are safety gaps necessary??
> ?
> I changed the Subj: line to reflect the topic...?
> ?
> Way to stir the mud, Bart! It's good to make us examine our practices.?
> ?
> I thought about your post quite a bit. Yes, it does seem hard to justify a 
> separate static safety gap that is in parallel with the main static gap. I 
> think we've had to do some hand waving and wiggling when we describe to 
> newbies the procedure for separately setting the main and safety gaps. And 
> I fully agree that a static gap is extremely unlikely to fail in the way 
> that an RSG might. So I was about to join the heresy and agree that safety 
> gaps appear to be redundant and unnecessary with a static gap.?
> ?
> I slept on it and it dawned on me this morning. What happens when a 
> streamer strikes the primary? If one exists, the 3-terminal safety gap 
> fires, channeling the streamer's energy safely to RF ground. If one didn't 
> have a 3-terminal safety gap, the only path for that streamer energy is 
> through the NST. I think the NST would be happy that the 3-terminal gap 
> exists!?
> ?
> So I stand by the advice to use a 3-terminal safety gap.?
> ?
> Regards, Gary Lau?
> MA, USA?
> ?
>> -----Original Message-----?
>> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On?
>> Behalf Of bartb?
>> Sent: Tuesday, June 17, 2008 8:53 PM?
>> To: Tesla Coil Mailing List?
>> Subject: Re: [TCML] Chokes and Terry filters?
>>?
>> I think all of us are preaching proper gap spacing via NST and gap?
>> setting (workbench approach) which eliminates the various electrodes?
>> chosen. Another aspect to consider is that DC typically runs at about?
>> 1.3 x Cres for his cap size. So he is taking advantage of some resonant?
>> charging as far as bps is concerned. The static gap still clamps the?
>> voltage regardless and I agree is the main problem with NST failures.?
>>?
>> If I were to weigh in on the filter discussion, I would say the chokes?
>> are unnecessary with a filter. However, I have even pushed my gap?
>> setting wide enough to kill an NST even with a Terry filter installed.?
>> This is when I realized the safety gap was useless due to my gap setting?
>> and sort of what drives me to stress the margin between safety and main?
>> gap needs to be large enough to allow the safety gap to work, otherwise,?
>> it's just a waste of labor and electrodes.?
>>?
>> I do push my transformers with what I can get away with. If it fails,?
>> I'll just fix it or replace it. There are probably a few like me out?
>> there on that subject. With that in mind, I've even been thinking about?
>> doing away with the safety gap (my static gap coils only). The reason is?
>> I have little margin and it's an annoyance when set correctly and?
>> useless when it's not an annoyance.?
>>?
>> The fact is, the probability of a decently built static gap failing is?
>> slim to none. So, what's the point of the safety gap in that type of > 
>> system??
>>?
>> Take care,?
>> Bart?
>>?
>> Lau, Gary wrote:?
>> > Indeed. I think the reason that DC has been successful in not killing > 
>> >  > NST's is his?
>> conservative approach to keeping static gap width small. That, more than 
>>  > using?
>> any kind of filter, is the key to long NST life, and that's what we 
>> should > be?
>> preaching. But human nature being what it is, the desire to increase > 
>> performance?
>> has us opening the gaps to the max, and that's where Terry filters become 
>>  > useful.?
>> >?
>> > Regards, Gary Lau?
>> > MA, USA?
> ?
> ?
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