Re: rectified nst's and hookup

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jimlux-at-earthlink-dot-net>


> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>
> Hi Marc,
>
> Calm down buddy! :-))
>
> Last weekend we quickly whipped together a NST to DC converter here out of
> spare diodes for a 20kV can crusher.  So the technology is a proven one
;-))
>
> There are a few things to check if you are not getting any output past the
> bridge.
>
<<snip>>
> 4.  The diodes may be bad :-((  If they are shorted or leaky for some
> reason, then it won't work.  You can take them one by one with the output
> of the NST set to a voltage that will just make a small arc and see if
they
> pass current in one direction and block in the other.  I assume they "are"
> obviously diodes and not some other weird part.
<<snip>>

It's real easy to kill the diodes in these circuits and not be aware of it.
My first exploding wire system used a bunch of microwave oven diodes and a
NST to charge the cap. After the first shot, I couldn't get the cap to
charge past 7kV (as opposed to 20 kV).  I assumed I had killed the cap..
Nope... killed the diodes... HV diodes, in particular, can be "partially"
blown because they consist of a whole bunch of lower voltage diodes in
series. If, say, 5 out of 10 diodes die (shorted), then all of a sudden,
your 12 kV diode just became a 6 kV diode.....

A NST, variac, and ammeter makes a handy test setup...