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Re: Strike Rail

At 08:37 PM 03/27/2000 -0600, you wrote:
>Tesla List wrote:
>> 
>> Original Poster: "Bob Berg" <berg_bob-at-hotmail-dot-com>
>> 
>> I think this is a simple question:
>> I have seen some coils with and with out strike rails.  Is a strike rail
>> needed? Is it used to protect primary from taking hits from the seconday?
>> Thanks
>> Bob
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>
>
>
>Hi Bob ...
>
>a strike rail is really nice to have ...  it helps tremendously in
>averting the streamer strike to the primary  ( which can cause nasty
>stuff to happen like blowing caps and trannies) but if you are really
>good at field shaping with the toriod ( only Terry is that good ;)  )
>then do with out the strike rail ...   :) 
>
>
>Scot D
>

Hi Scot and All,

	I don't use strike rails.  I have computer modeled my coils and
"virtually" tested them for all the fault conditions I can think of.  My
filters and such "should", and have, protected the systems against
secondary to primary strikes and such.  I have done some deliberate testing
(knowing that a failure will blow the snot out of something) and all has
gone well.  However, the models do indicate the if one does not do
everything "just right" things can go bad fast.  So if you have good
grounds, safety gaps, and filters, you can probably live without strike
rails. But for most people they are a darn good idea.  If I blow something
up, I would just write it off as an interesting science fact, but most
people are a little more sensitive to blowing stuff up.  Safety gaps that
can take a lot of current seem to be key in this.  They have to take up to
1000 amps off the primary and take 100s of kV (at lower current) from the
secondary.  I would call the risk of running without rails as low to
moderate for most ~1KVA systems.

"I" also advocate making the secondaries long enough that such strikes are
not likely.  Field mapping will allow your powerful long streamer coil not
to be hampered by "shorting" to the primary system.  Many people warn
against making a coil too long and thin but it is also desirable to keep
the secondary toroid far enough from the primary so as not to arc over and
basically limit a coil's streamer length.

Cheers,

	Terry
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