Re: MMC Protection SGap current limit

To: tesla-at-pupman-dot-com
Subject: Re: MMC Protection SGap current limit
From: "sundog" <sundog-at-timeship-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 15 May 2000 21:20:55 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi all!
        Mmmkay...just finished re-re-re-re-reading the below post
by myself and the answer.  Thought about it a lot, and am still
thinking.  Been up 2 days straight, so I'm just thinking and not
coiling to see if the thoughts are right.  Here's what I thought so
far...
    Put an inductor, a spiral of wire (aka, an old primary),
encased in a wooden/plastic/whatever box in series with your saftey
gap, so the inductance limits the amperage of the spark gap.  Not a
bad idea, but bulky, is another HV accident waiting to happen, etc.
I guess a helix in a box would work, but the inductance on those
are pretty low compared to the flat spiral (why?, I just know it
is, but not why).   Mkay...so the cost of the copper tubing, wood,
etc would outcost the resistor...why not just put the saftey gap in
parallel with the main gap, so if it does fire for some reason,
it'll perform the same function?  THen you have no need to try and
limit the amperage across it, and the coil will be none the wiser.
So I'm envisioning a nst with it's own saftey gap, the cap, the
cap's saftey gap, the main gap, then the primary...sooner or later
the saftey gap will fire, and the MMC's have shown they can take
the abuse of overvoltages (unless you're *really* pushing it!), and
the inductance limits your amp-pulse.  problem solved? dunno...but
I believe if the saftey has to fire, put that puppy to work!
                                        A very tired  Laters!
                                                        Shad
-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Sunday, May 14, 2000 11:39 PM
Subject: Re: MMC Protection SGap current limit


[snippers!]


>> case, I like the idea of putting the saftey gap in parallel with
>> the main gap, and set to fire a few KV higher...I'm assuming
most
>> of this deals with rotarys instead of static gaps, where missing
a
>> firing is more likely.  If firing the main gap, through the
primary
>> is safe, why not just coil a helix of tubing, say, 35-40 ft, in
a
>> box, seal it, and run that in series with your saftey gap
instead
>> of a resistor?  Definately cheaper, and should look identical to
>> the caps as the primary you're already pushing (for the most
part
>> at least)....Just a my $.02.....
>>                                                         Shad
>
>What's different is that the main gap has an inductor, namely the
>primary coil in series with it. The surge impedance of the coil
limits
>the peak circuit current.
>
>Regards,
>Malcolm
>
>
>