Re: MOT coil performance

["Gregory R. Hunter" <ghunter-at-accucomm-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Chris,

The high current and low voltage of your supply is a recipe for headaches.
I suggest using two half-wave voltage doublers with the MOTs.  These will
boost your peak voltage to around 12kV and reduce the spark gap current.
Also, the pulsed nature of this supply will help prevent formation of a
power arc by giving the gap a half-cycle to rest between each current pulse.

My own limited experience with two unballasted MOTs sent me back to the
voltage doubler scheme in a hurry.

Cheers,

Greg

At 11:22 AM 08/17/2000 -0600, you wrote:
>Original poster: "LOCKWOOD, Chris J." <clockwood-at-orbeng-dot-com.au> 
>
>Hi,
>
>I'm going to make a new coil from scratch, based on 2 MOTs, and a 0.1uF 20kV
>cap, which I already have.
>
>What size sparks should I expect from an 'optimised' coil/gap config? 
>
>Given the low voltage (~6kV pk) from the supply, I'd assume that the coil
>would need to be tuned to quite a low F, to get the primary (= gap) current
>down. Any suggestions (from experience) as to the most efficient
>configuration of gap, primary L, and secondary dimensions?
>
>My 4.5" coil fried last night. At best was only getting 30" ground strikes
>from a twin static gap and this supply. I'm sure this could be much better,
>with a more 'optimal' setup... Gave up on the DC supply for now~ MOTs are
>more compact.
>
>Chris
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