Re: TT-42 update
> Original Poster: FutureT-at-aol-dot-com
Glad to hear your getting your portable coil running well. As I've known
for quite some time now, you have an excellent system in place to spin your
toroids. Just how large of a toroid can you spin? I've avoided spun toroids
mainly because I need to be in the 50pF range on my coil (is this too much
for your spinning system?).Refering to your arc length; Your running 120
bps on a 12/30 NST? So your beyond the input watts equation. It seems to me
you could drive a larger toroid for greater arc length. Not much larger in
pF, but a bit. Have you tried this? Also, I think a few more bps would
help, but you can't go too far with it before the energy at the toroid
actually decreases (240 is just about maxed out with your current setup). I
know you've tried higher bps in the past and you were not impressed. I
believe there is optimum bps rates for each coil determined by the entire
system, including the top load.
P.S. Beautiful job on the TT-42.
> Hello coilers,
> I finally got the TT-42 coil running with it's new base, so it's now a
> portable TC. The bottom of the base is a piece of plywood about
> 15" by 14". Three wooden legs from old style TV's hold a "wye"
> shaped piece of wood above them, and the flat primary is mounted
> 2.5" over that. The new small rotary, the unpotted 12/30 NST, and
> the Maxwell 0.0147uF cap is mount on the plywood. The coil
> definitely has a unique look to it. The entire TC is 39" tall from the
> base to the top of the top toroid. I'm using a 1.5" x 6" spun aluminum
> toroid with a 4" by 13" spun aluminum toroid above it.
> I've posted new photos showing the TC with the new base at my
> The secondary has a wooden post at the bottom, with a brass
> screw at the bottom of the post. There is a wooden socket mounted
> to the "wye", and there is a brass flat head screw at the bottom of the
> socket, so when the secondary post is dropped into the socket, the
> brass screws make contact. This way, the secondary does not need
> any kinds of bolts, etc to make the electrical ground connection.
> This makes it convenient for fast setup in the portable realm.
> I built a small simple safety gap to ground out any strikes that might
> loop down and hit the primary. The NST doesn't have any other
> protection. There is no PFC. I just used wire nuts to connect the
> power cord to the NST primary. I still have to improve the method of
> tapping the primary, to give me more tune points. I think the tuning
> is off slightly because my sparks are only about 38" instead of 42"
> max. I was getting 42" before when tapped at 15 turns, but now that
> I'm tapped at 14 1/2 turns, I'm getting just the 38" sparks.
> John Freau