RE: Better performance

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

 > Original poster: "Sam W." <HAZAA_69-at-hotmail-dot-com>
 >
 > I have a coil running on a 12/60 nst
 > 4.5" x 30" secondary w/21 AWG magnet wire
 > Primary:8 turns of 10 AWG insulated wire
 > Spark gap is a single static with no pressurized air for quenching
 > mmc 25 0.33 uF caps rated at 600VAC in series to make
 > 12500VAC 0.0133uF
 > choke 200 turns 21 AWG
 > 4" flexible aluminum ducting covered in aluminum tape
 > 2" flex aluminum ducting covered in aluminum tape
 > (double toroid)
 >
 > im getting like 3" breakout, with only 9" going to a grounded pole. I
 > couldnt get any thin walled copper tubing, so i used
 > insulated wire rated
 > at 15 kv. if i replace the primary and change the spark gap
 > will i get
 > bigger sparks? im reading about people with similar setups
 > getting like 3-4
 > ft. sparks. This was my first coil, and i did it for science
 > fair. I was a
 > little dissapointed with performance. I dont want to use a
 > rotary gap,
 > cause i cant get a synchronous motor, and asynchs will blow
 > my nst. PLEASE
 > HELP!
 >

A good blower/sucker or RC gap is the first thing you should try. Improper
quenching of the spark gap will allow the energy in the secondary to flow
back to the primary, decreasing the output.

Try rewinding the primary with any ¼" soft copper tubing. It should be
easily available (where are you?) e.g. from a refrigerator repair shop. Or
larger wire at least - the primary coil in your system has to handle peak
currents of up to 400A when the primary cap discharges!

Also ensure that there is at least 8" of space below the primary coil (think
how big the magnetic field around it is).

Let us know how you get on,

Tom L.