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Re: Neon power draw, and resonant stresses.




From: 	Mad Coiler[SMTP:tesla_coiler-at-hotmail-dot-com]
Sent: 	Tuesday, September 02, 1997 6:50 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Neon power draw, and resonant stresses.

>From: 	Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
>Reply To: 	bert.hickman-at-aquila-dot-com
>Sent: 	Monday, September 01, 1997 6:18 PM
>To: 	Tesla List
>Subject: 	Re: Neon power draw, and resonant stresses.
>
>Tesla List wrote:
>> 
>> From:   Mad Coiler[SMTP:tesla_coiler-at-hotmail-dot-com]
>> Sent:   Friday, August 29, 1997 11:43 AM
>> To:     tesla-at-pupman-dot-com
>> Subject:        Re: Re[2]: Neon power draw, and resonant stresses.
>> 
>> >From:  FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
>> >Sent:  Friday, August 29, 1997 4:22 AM
>> >To:    tesla-at-pupman-dot-com
>> >Subject:       Re: Re[2]: Neon power draw, and resonant stresses.
>> >
>> >In a message dated 97-08-28 15:56:55 EDT, you write:
>> >
>> ><<
>> >> John, you have brought up an issue I had asked the list about and
>> never
>> >> got a response.  You say "If it's value is such that it resonates
>> with
>> >> the leakage reactance of the neon trannie..." How is this 
determined.
>> In
>> >> the designing phase how could one determine if this would happen? 
And
>> >> does this stress the neon two much, or is it ok as long as the gap
>> fires
>> >> to discharge it?
>> >
>> >> Still resonating in Ohio,
>> >> Mad Coiler
>> >>  >>
>> >
>> >Mad,
>> >
>> >I'm unable to find the formula, I was hoping someone would re-post
>> >it for you again.  "does it stress the neon too much?"... depends on
>> >what you mean by too much.  Certainly, it stresses it more than
>> >without resonant charging.  Yes, by limiting the gap spacing, you 
can
>> >limit the voltage across the trannie, and still obtain the benefit 
of
>> >the increased current draw. None of my neons have yet burned,
>> >and I've been using this resonant method for years.
>> >(I did burn out a couple of neons...but that was when I used a
>> >non-sync rotary gap!)
>> >
>> >John Freau
>> >
>> >
>> 
>> John, when I asked about the stressing thing my only concern is about
>> the neon - i mean will it eventually damage it. I see you haven't had
>> any problems burning up neons with this so you have answered my 
question
>> about that. But about figuring the C for 60Hz resonance...
>> 
>> Mad Coiler
>
>Mad Coiler and all,
>
>You'll achieve low frequency resonance when the inductive reactance of
>your neon(s) is "neutralized" by the capacitive reactance of your tank
>cap. For 15 KV neons, this works out to be just around 0.01 uF for 
every
>60 MA of current if you are running off a 60 Hz power source. The tank
>capacitance will need to be about 20% higher if you run off a 50 Hz
>power source. 
>
>For example, suppose your neon is a 15 KV 60 MA. It's effective output
>short-circuit impedance is:
>   
>    XL = 15000/0.060 = 250,000 Ohms (reactive).
>
>At an incoming line frequency F, your tank capacitor's capacitive
>reactance will be:
>
>    XC = 1,000,000/(2*Pi*F*C) Ohms, where C is in uF
>    
>Setting XL = XC, and solving for C:
>
>     C = I/(V2*Pi*F)  
>     where: 
>         I = total sum of faceplate ratings of neon bank in MilliAmps
>         V = faceplate RMS in Kilovolt for neon bank
>         F = Incoming Line Frequency in Hz
>        Pi = 3.14159   
>         C = in uFarad
>
>     C = 60/(15*6.28*60) = 60/11,304
>       = 0.0106 uF
>
>By plugging in the output RMS voltage and current for the neon
>transformer (or bank of neon transformers), you can solve for the
>appropriate tank cap value. Since this seems to be a question that 
comes
>up fairly often, I've generated the tables below for 9, 12 and 15 KV
>neons banks for both 60 and 50 Hz sources for typical low and medium
>power ranges. Since the "Q" of the neon-cap LC circuit is fairly low
>(5-10 typically), if you're within about 15% of the ideal tank
>capacitance you'll encounter resonance effects. For example, the point
>at which the spark gap JUST begins to fire intermittently will be
>reached at a relatively low variac setting (about 15% on my system).
>Remember to keep your gap distances reasonable to avoid overvolting 
your
>transformers or tank caps(!), and don't attempt to run the system with
>an asynchronous rotary gap.     
>
>   Bank       (uF)        (uF) 
>  Current     60 Hz       50 Hz
>  -at- 15 KV:  Tank Cap:   Tank Cap:
>  =======   =========   =========
>   30  MA     0.005       0.006
>   60  MA     0.011       0.013 
>   90  MA     0.016       0.019
>  120  MA     0.021       0.026
>  150  MA     0.027       0.032
>  180  MA     0.032       0.038
>
>   Bank       (uF)        (uF) 
> Current      60 Hz       50 Hz
> -at- 12 KV:    Tank Cap:   Tank Cap:
> =========   =========   =========
>   30  MA     0.006       0.008
>   60  MA     0.013       0.016 
>   90  MA     0.020       0.024
>  120  MA     0.027       0.032
>  150  MA     0.033       0.040
>  180  MA     0.032       0.048
>
>   Bank       (uF)        (uF) 
> Current      60 Hz       50 Hz
> -at- 9 KV:     Tank Cap:   Tank Cap:
> ========    =========   =========
>   30  MA     0.009       0.011
>   60  MA     0.018       0.021 
>   90  MA     0.027       0.032
>  120  MA     0.035       0.042
>  150  MA     0.044       0.053
>  180  MA     0.053       0.064
>
>Hope this helps!
>
>-- Bert H --
>

Bert, thanks for the data. It will be most useful.

Mad Coiler