Re: Help w/ Chokes

Hello Coilers,
        JParisse-at-DDLabs-dot-com wrote:
>> I know there has been a lot of discussion 
>>regarding choke coils and I'm wondering if someone could guide me in 
>>building a pair of appropriate chokes. I have limited space for the 
>>chokes. If I use air core chokes, I can only accommodate a 2 dia. x 8 
>>coil form.
        Jim Fosse then listed a number of fine examples of folks who had
successfully blown transformers due to kickback problems.
        Add me to your list.  I have blown out a 15kV 30 mA and a 9kV 150 mA
after trying a number of choke combinations.  My latest attempt -at-9kV went up
in smoke three nights ago, after several really nice runs.  I was using two
iron powder chokes in series on each side of the circuit.  I haven't
measured it yet, but my guess is about 5-10 mH total inductance on each side
of the high voltage line, with doorknobs across each half of the transformer
to ground.  My next attempt will definitely include resistors for damping.  
        I can also provide experimental evidence that running 15 kV through
a 90 mill (3-30 mill plates back to back) flat plate capacitor is a really
bad idea!
        My search for a suitable potential transformer continues.....
Mark S. Rzeszotarski, Ph.D.