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Primary field strength


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From:  Michael Nolley [SMTP:mhnolley-at-willamette.edu]
Sent:  Friday, August 14, 1998 6:34 PM
To:  Tesla List
Cc:  'Tesla List'
Subject:  Re: Primary field strength


> From:  chris.swinson [SMTP:chris.swinson-at-zetnet.co.uk]
> Sent:  Friday, August 14, 1998 3:20 PM
> To:  tesla list
> Subject:  Primary field strength
> 
> Hi all,
> 
> I discovered today that my coil's field strength drops off at about 38".  I
> used a 8Kv 30ma NST.  My secondary ( 38" ) and cap ( 11.45nf ) were not used
> at first.  This gave me a clear indication that the field rose to a hight of
> 38".  I could gain about another 2" spark if a increased the coil's length
> but thats not the issue here.
> 
> When I tried a 6.4nf cap, with only 1mm spark gap, The field was so big that
> it filled the whole room.  If I had used a 5mm gap ( about max ) Wouldn't it
> be possible to have a secondary say 200" in hight and still power it off the
> 8Kv 30ma source.
> 
> The secondary would still be in the field of the primary as the cap give's a
> high current boost each cycle.
> 
> But even so, why am I told not to go over 24" for my secondary height ?
> 
> The only problem I can see is the resistance of the secondary would be huge
> due to the extra wire, but I can double wind my coil to get around this.  So
> in fact I could get about a 72" spark off a 200" coil, with the power still
> being only 8Kv -at- 30ma.
> 
> I know Tesla used large inductive coils, perhaps he did this to use bigger
> caps and get better effieciency.
> 
> The only other drawback being the frequency would drop due to the high
> inductance, but my specualted coil at 200" high, would only give 44mH
> inducatnce anyway.  My 36" coil is only about 8mH anyway.  So the way I see
> it, its a win-win situation.
> 
> Can anyone confirm this or have anything to comment on ?
> 
> By the way, I'm a bit think, so whats BTW stand for ?  Its driving me mad !
> 
Hehehehehehe....  You're a bit what? Thick? 
	Sorry, Chris, I'm not experienced enough to give you all the help 
you need, but I think that as the height/inductance and self-capacitance 
of the coil increases, the size of the bangs would have to increase as 
well in order to make it ring.  Just because the field grows large 
without the sec. doesn't mean that it will effectively drive it once it 
is put in... Can't very well make the Liberty Bell ring with a toothpick....
	Good luck to you BTW.
			Mike



> All the beST,
> Chris.
> 
> chris.swinson-at-zetnet.co.uk
> www.users.globalnet.co.uk/~mega01/    <--- moved site to...
> www.users.zetnet.co.uk/mega.disczine/
>