Re: Convert your MOT to NST?

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

Original poster: "jimmy hynes by way of Terry Fritz <twftesla-at-qwest-dot-net>" <chunkyboy86-at-yahoo-dot-com>


isn't the only thing limiting the current to 100ma or so the driver? by using
more capacitors and high power igbts, or cutting an air gap and running it as a
flyback, couldnt you get 10kv and 500ma or more out of a mot? 

 Tesla list 
>
> wrote:  
> Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <youngs-at-konnections-dot-net>
>
> Hi list,
>
> MOTs are sometimes used to power TCs.  MOTs are typically free, don't break 
> down like NSTs often do, and are good for 1 KVA or so.  On the downside, the 
> 2 KV voltage is on the low side, requiring 2 or 4 in series and/or voltage 
> multipliers, and the current is rather high, making it tough to cool and 
> quench spark gaps.  And their self-current limiting (magnetic shunts) are 
> not all that effective.
>
> Can these limitations be overcome?  Yes, sortof.   I tried an experiment and 
> got around 10 KV out of one at reduced current - probably 100 ma or so 
> average.  How?  By driving the MOT from a lamp dimmer and 15-30 mFd cap in 
> series.  Same idea as driving an ignition coil for a TSG, only wi! th more 
> input power.  The voltage is much higher than normal because of the more 
> rapidly changing magnetic field, and the average current goes down because 
> power is applied for only part of a cycle.
>
> The insulation of the MOT I tried did not break down for output arcs that 
> would bridge 1/4 to 3/8 inch.  It would be a good idea to immerse a MOT run 
> this way in oil to improve its chances for long term survival.
>
> Using just a straight dimmer, the operation was a bit flaky, as others have 
> reported in trying to drive an inductive load.  I didn't try adding a second 
> triac, but I am sure that would improve performance a lot.
>
> So one can get NST-like performance out of a MOT if driven in this unusual 
> way.  A pair of them would be good for 16-20 KV at a 100 ma or so, depending 
> on the size of the series cap used (use motor run caps).
>
> Just something to consider and tinker with if you are so inclined.
>
> --Steve! 
>
>
>
>
>
>
>
>
>
> JImmy
>
>
>
> Yah! oo! - We Remember
> 9-11: <http://dir.remember.yahoo-dot-com/tribute>A tribute to the more than 3,000
> lives lost