RE: primary tapped at 2 turns

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

Changing only the NST's voltage and/or current should not require changing
the primary tap setting.  BUT, one would usually change the tank capacitor
value when changing the NST to maintain best efficiency, and obviously,
when changing the tank cap, the primary tap would also have to change to
remain in tune with the secondary.

When going from a 7.5/60 to a 5/120 power supply, the tank cap would
normally increase in value and this would require a smaller number of
primary turns to remain in tune.  Did you change your cap size and forget
to mention this?

As an aside, a primary tapped down to only two turns would be inefficient.
The pri-sec coupling will be low and gap losses will be high.  I'd
recommend increasing your secondary top load to allow you to use more of
your primary.

Gary Lau
MA, USA

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Sunday, February 17, 2002 10:55 PM
To:	tesla-at-pupman-dot-com
Subject:	primary tapped at 2 turns

Original poster: "colin.heath4 by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<colin.heath4-at-ntlworld-dot-com>

hi all
        i have my primary tapped at two turns now instead if 8 turns before 
i was running a 7.5kv 60ma supply and i am now running 5kv 120ma 
is it normal for the tap to go inwards rather than out because when i changed
from 6kv 30ma to 7.5kv 60ma it went further out but now its two turns on 120ma
5kv
any ideas will be much appreciated
many thanks
colin heath