Re: power supply questions

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

Original poster: BunnyKiller <bunikllr-at-bellsouth-dot-net> 



Tesla list wrote:

>Original poster: "Christoph Bohr" <cb-at-luebke-lands.de>
>Hello!
>
>I have two questions about changes I want to make to my power
>supply:
>
>1st: I only have one variac to controll the main HV transformer.
>Currently I use it in standard configuration and additional
>inductive ballast to limit the current. By means of that I
>experience a lack of output voltage due to the voltage drop in
>the ballast / variac. Can one use the variac to controll the
>current ( in series ) WITHOUT using one to controll voltage?
>Would that give a voltage gain?
>
>2nd: I thought about using DC to feed my coil by rectifying the
>xformer output with a series setup of 1N4007 diodes under oil and
>charge a 30nF cap for cmoothing purposes. The main C1 would be
>60nF. Can this be done or has the smoothing cap to be bigger than
>tha primary cap?
>
>Any suggestions welcome
>
>Sincerely
>
>Christoph Bohr
>
>
>Hi Christoph..


first off   what size variac  and what size transformer?

normally inductive ballast doesnt drop voltage but resistive will....
the problem with using a variac to control current is that when you get 
close to 0 or 100% on the variac ( depending on how you use it )  the 
current thru the variac gets too intence and it gets HOT ...    an 
inductive ballast set to maximum settings shuold be used and a varaic
is used to set the voltage...

SD