The Not-so-indestructible MOT

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

Original poster: "Jason Johnson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <hvjjohnson13-at-hotmail-dot-com>

Well the other night I had ran my coil and had a direct strike to the
transformer (dual MOTs in a MDF box filled with oil) setting on the bottom deck
of my tesla coil. At first I thought the worst and immediately removed power,
but after an inspection I re-applied power and the coil fired right back up but
performance rapidly declined from 5'+ arcs to nothing in a few seconds. I put
the coil away for a while. Just the other day I finally went back out to the
cold garage to have a look.I pulled the transformers off the coil and put them
up on the bench and checked the continuity between the various terminals.
Everything checked OK but upon powering up the transformers some nasty smelling
bubbles came up out of the oil at any signifigant voltage input. I'm assuming
its a high voltage short to the core. So maybe MOTs aren't indestructible but
not many transformers can stand a direct hit by 500,000+ volts. The good thing
is that the MOTs were free and I've only got to replace one of the two.
 
Jason Johnson