[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Magnifier Driver coil design
- To: tesla@xxxxxxxxxx
- Subject: Re: Magnifier Driver coil design
- From: "Tesla list" <tesla@xxxxxxxxxx>
- Date: Sun, 17 Apr 2005 20:31:05 -0600
- Delivered-to: email@example.com
- Delivered-to: firstname.lastname@example.org
- Old-return-path: <email@example.com>
- Resent-date: Sun, 17 Apr 2005 20:31:22 -0600 (MDT)
- Resent-from: tesla@xxxxxxxxxx
- Resent-message-id: <X3Dk_D.A.LtF.ovxYCB@poodle>
- Resent-sender: tesla-request@xxxxxxxxxx
Original poster: Steve Ward <steve.ward@xxxxxxxxx>
I was talking to Jimmy just a minute ago and he pointed out that i
should figure out the over all coupling between all 3 coils, that is,
treating the L2 and L3 as 1 coil. I found a formula on Antonio's
site, looked like this:
K(L1L2L3)=(KL1L2)*sqrt(L2/(L2+L3)). I ran my original design through
there with the ~4mH secondary and got a pathetic .07 for the K! Im
almost certian that wont work too well.
So here is my revised design:
Tertiary: 8.1"x45" winding of 46awg with a 36" toroid up top. L is
190mH, loaded Fr is 48khz. Im going to start off just using my
original secondary, since i *know* it will take lots of abuse for
producing long sparks. Will look at shorter windings later when
teslathons approach at the end of summer.
Secondary: 12.25"x18", 22awg winding. L is 55mH. With a 17"x2.5"
toroid on top the Fr of that coil is 123khz (not that this should
Primary: 20" diameter, 9.5 turns, .5" diameter conductor, .4"
spacing. 53uH, and using a .45uF tank capacitor. Fr 32khz.
With a K (pri/sec) of .5, i calculate an overall K of .24, which is
right where i want it. I looked at what i had done with the little
DRSSTC magnifier and noticed that my driver L to resonator L was a
ratio of about 1:3.2. I felt that the driver is producing a little
too much voltage, so a ratio of 1:3.5 seems about right for a start,
so that is how i arrived at the 55mH for the secondary coil with a
Keeping the coils from arcing will be a fun challenge. Must not have
any sharp points on my primary! I might also look at reducing the
Bang length on my driver so that i can try running greater than 500bps
and keep the power reasonable and see if anything fun happens :-).
On 4/17/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> Hi Steve,
> I have played a "little" with tree coil systems so don't take what I say
> with much weight compared to say Ed Wingate and others who know a ton about
> It seems to me like the third coil is pretty conventional other than its
> based is raised up and insulated for voltage clearance on the high voltage
> The voltage between the secondary and third coil is sort of a percentage of
> the top voltage roughly based on the two inductances. You don't want that
> voltage to go too high or you will have problems keeping the secondary top
> or third coil base from arcing. Corona rings may be needed.
> I think the primary to secondary coupling is still pretty close to say 0.2
> if you consider the secondary and third coil as one. Since you don't want
> the secondary top voltage to be super high, you need a fairly small
> inductance with big coupling between the primary and secondary. But don't
> worry about it "too" much.
> In general, I think just about anything will work. Antonio has come up
> with some cool optimizations, but I think just about any three coil system
> that does not arc over in the wrong place or has some obvious "boo boo"
> will work fine.
> I still have my magnifier thing on the "to do" list, but now I guess it
> will be run with a DRSSTC too ;-))
> BTW - If you can run at 500-1000BPS without any big added work, it may arc
> further... I am still looking into that...