Re: Gap voltages AC vs. DC (fwd)

From: 	Tesla List Owner[SMTP:listown-at-pupman-dot-com]
Sent: 	Friday, January 02, 1998 1:01 PM
To: 	tesla-at-stic-dot-net
Subject: 	Re: Gap voltages AC vs. DC (fwd)

---------- Forwarded message ----------
Date: Fri, 2 Jan 1998 00:43:35 -0700
From: richard hull <rhull-at-richmond.infi-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Gap voltages AC vs. DC

At 05:34 PM 1/1/98 -0600, you wrote:
>From: 	Adam[SMTP:absmith-at-tiac-dot-net]
>Sent: 	Thursday, January 01, 1998 3:56 PM
>To: 	tesla list
>Subject: 	Gap voltages AC vs. DC
>I know about the table for DC sparkgap voltage breakdown that is in the 
>CRC handbook.  I decided to do a little gap experiment to see if 60Hz 
>voltages had similar breakdown voltages.  My AC results turned out not to 
>be anywhere near the DC test results in the CRC handbook.
>I used a Powestat 116 7.5A variac, a wavetek 27XT DMM measuring voltage 
>out of the variac, and a webster 10,000V 23mA transformer in brand new 
>perfect condition.  My gap is made from two machine bolts, with 2.5cm 
>dia. round heads, in fairly still air, gapped using feeler gauges.  I 
>used a muffin fan to air out the gap between tests, and averaged the 
>results of 4 measurements at each gap setting.  
>Note that since I do not have a 40kV probe, I am measing voltage input to 
>the OBIT and calculating ouput voltage, assuming on the OBIT to be 
>linear.  I'm not sure if this is a good assumption or not.  
>Gap       Variac    Volts RMS   Volts Peak	
>0.030       32        2667         3771			 	
>0.060       53        4416         6246			 
>0.090       72  		    6042         8544			 
>0.120       92  	     7667        10842			 
>0.150      110        9167        12964			 
>0.180      128       10667        15085	       
>I am going to repeat this with sharp points later on.
>Adam Smith
>Epoch, Inc. Digital Music Project
>www.tiac-dot-net/users/absmith/                 MP3 Demo Tracks Now Available!

Neon sign transformers are pretty much pieces of crap they are not even
close to there name plates to with say 20%.  They don't have to be.  There
is no such thing as precision neon lighting.  Only a true potential
transformer can be relied upon in a measurement like you are attempting.
Also the voltage of breakdwon is based on the peak voltage and not the RMS
values.  (1.4 times higher)

60 hz values of peak voltage breakdown for the exact same electrodes should
track fairly close to the DC values.  +/- 5%.

Richard Hull, TCBOR