The 4" Powersupply is a MOT based powersupply. It has itīs own ballast MOT to run at ca. 4KVA. Itīs 4 MOTs in series for 8KV @ 500mA. Because of the bad isulation of some MOTs i put the two outer MOTs in Oil.
I hope to get some great sparks with this supply. My goal would be sparks with a lenght of 3 times the windinglenght of the coil. I have reached 2 times the windinglenght (1250mm) so far, but hadnīt enough space to go to higher levels. I hope to get 1875mm sparks sometime.