VTTC

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

Original poster: "James by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mustang3-at-cox-dot-net>

Hi group,
    I've been working on my toob tesla coil. The new plate transformer weighs
in at 65 lbs. Also made main chassis a lot larger. Secondary is 6" dia X 27"
winding of #27. Has two 500W triode toobs. Plate transformer is a 6400V. C.T. -at-
.75A. Was a 1/2 wave voltage doubler(uwave oven PS, 4000 volt pulses). I made
the rectifier modular. It can be configured as fw bridge(with or without a
filter cap), fw wave ct(3200 V.D.C.), or 1/2 wave. Naturally all of the weak
parts ran off and hid in the trash. There is something about Tesla coils and
letting the smoke and flames out of parts.
     The value of the plate cap is .0056 uf. My plate cap is NOW rated at 9 A.
R.M.S.  -at- 100KHz. Tesla coil operates at 126KHz. The plate cap gets pretty hot
at high input power. So does the #10 primary coil. Spark length is 27-28
inches. Tuning is affected by input power. The frequency goes down as the input
power goes up. More spark length requires lower fo. i.e. larger cap. I tune for
max spark at full power. The toobs are doing well considering I'm putting 6000+
volts on the plates. Rated at 4000 volts.
     The effect of running it on filtered D.C. is most spectacular; the corona
is a soft hiss about 4" long. If a fluorescent light is brought to the
discharge point, an 18 inch sheet of flame jumps to the light. However the
spark length is down using the fw rectifier. Best spark length is using th 1/2
rectifier and no filter cap. I guess this is because the duty cycle is down and
the voltage might rise a little higher.
Specs:
Pri coil:12" dia X 3" tall  #10 THHN wire - 28 turns
Sec coil: 6" dia X 27" winding  #27 wire - no topload
Plate cap: 5.6 nf -at- 10 KV
tickler coil:12" dia 20 turns #20 wire - spaced 1/2 below pri coil
grid leak:cap .003    resistor 7.5K -at- 300W
toobs:two 500W. triodes
                                                                           
                                                 Later,
                                                                           
                                                     James