Continued Problems (fwd)

From:  fxphoto [SMTP:fxphoto-at-centuryinter-dot-net]
Sent:  Monday, May 11, 1998 2:57 PM
To:  Tesla List
Subject:  Re: Continued Problems (fwd)

Hi Malcom,
 Thanks for the info. If I am understanding you properly then if I were to
add a 1H coil to the primary side of a 100 to 1 ratio transformer it would
show up on the secondary side as an additional 100H inductance.
 And if I were to put two 100 mH chokes on the secondary side they would
reflect back on the primary of the same transformer as 2mH.
                               Thanks again for helping me to understand
                                Bill Turbett

>> Upon further investigation, it
>> looks like there would be absolutely no affect on the Xl of the secondary
>> since these devices control the current before it reaches the primary.
>Wrong. Whatever choke you stick on one side of an ideal transformer 
>appears on the other with its value modified by the turns ratio. It 
>should be remembered that while chokes are at first glance the most 
>innocuous of current limiting devices, they do that with an expense:
>they store energy in order to do so efficiently (c.f. a resistance =
>Xl which doesn't and wastes a lot of power). You must model the 
>situation as the primary cap Xc at mains frequency (or break 
>frequency) plus Xl of the choke at whichever frequency is relevant.
>Just as you use Xc=Xl in the NST situation, you must use the same
>consideration for any system using an ideal transformer and 
>"limiting" choke. This is the essence of efficient resonant charging.
>    Re Ed's problem, it is apparent that he is experiencing this 
>phenomenon. There is no other way you can charge the primary cap to 
>beyond the o/c output voltage of the power transformer. The choice of 
>break rate should take account of this.