Re: High frequency impedance of a neon sign transformer

On Mon, 8 Apr 1996 20:00:48 +0700, tesla-at-grendel.objinc-dot-com, you

>>From EDHARRIS-at-MPS.OHIO-STATE.EDU Mon Apr  8 16:18 MDT 1996
new table is at ftp.bdt-dot-com/home/jim.fosse/neon_z.txt to allow
non-scrunched transfers:) (my mail program showed a beautiful table,
but read a zig-zaged one.	S - it's my program not your

>Note the 300kHz Z is twice the size of the impedance
>I measured on a differnt 15kV 60ma neon as previously 
>reported! I guess the contruction is somewhat different
>or else the potting compount is now less lossy?

 my jefferson 15K -at-60Ma is now air core, so it has a lot
 less iron to be lossy :)

Actually, I'm questioning the validity of my measurements? As I
thought about it today at work, I don't think that the standard
variable R in series with a Z will work, because the I that generates
the voltage drop across the resistor is 90 degrees out of phase with
the V across the inductor, so that the 1/2 voltage point DOES NOT
imply equal Zs.

>Also note that unlike the old neon, this one seems to have
>a resonance point at 600Hz or so! Very interesting. But you
>got 3kHz right?
3.35K, by watching the voltage peak with a fixed resistor.
1kHz = ~2.2meg, 10kHz = .22meg, With an iron core yet.

>Also, just to check, I tried about a decade difference in
>excitation voltages. The impedance remained the same to
>within about 10% for different drive voltages.
>-Ed Harris
Curiouser and curiouser! I've been doubting my methode/values, but, by
the same token, when I talked to the ap engineer at Magnecraf
(jefferson electric) last month, I got the impression that Neon sign
transformers were not DESIGNED but instead had been arrived at thought
a long process of trial-and-error. 

The different numbers that we are measuring may in fact be proving
this out!

	thoughts? comments?