Re: Getting the bugs out- a little help, please...

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

Original poster: Esondrmn-at-aol-dot-com 

In a message dated 11/10/03 5:17:34 PM Pacific Standard Time, 
tesla-at-pupman-dot-com writes:


>Hi all,
>
>I am in the process of rebuilding my piggie system and
>I fianlly got to start firing her up and tuning it in this eve-
>ning. I now only have a 9x30 toroid and I know that's a lit-
>tle small for my 12.75"x48.5" secondary coil as I'm think-
>ing more along the lines of a 12x48 toroid to properly
>utilize the avilable power from my coil. I did get a few
>8 to 9 ft. strikes to a metal ladder in my driveway this
>evening on just a rough tune-up.
>
>There are a couple of problems that I encountered
>though. First, my Wysock-built rotory gap is sync at
>480 bps and w/ .0825 uFD primary capacitance, I'm
>thinking that's a little too fast for the capacitor to ever
>be able to fully charge before discharging across the
>SG and that would definitely limit my sec. voltage gain.
>I haven't built a Freau phase adjuster yet either as I'm
>not sure that the phase angle would even be that big
>of an issue at 480 bps. I'm thinking about removing
>4 of the 8 rotory electrodes to go for 240 bps. Maybe
>some of you you more mathematically inclined mem-
>bers can tell me what the best bps rate range should
>be for this coil. My power supply is a 10 kVA, 14400
>volt PDT controlled through (2) paralleled 1256 variacs
>(up to 280 volts -at- 56 amps) and ballasted w/ a seriesed
>225 amp arc welder w/ the welding leads shorted. It just
>seems that I ought to be able get brighter,longer, more
>powerful sparks w/ my available power. Of course, like I
>said, I just roughly tuned it in tonight.
>
>The one other little problem that I did encounter when
>I really began to pour the juice to her was that the
>grounded strike ring would start flashing over to the
>outer turn of the primary coil. I thought that I had
>plenty of claerance here (about 3" or so) but maybe
>that autotransformer action is a little bit more of a problem
>than I thought. I'm tapped at just over 9 turns on the pri-
>mary, so I only have right at 3 more turns to build up
>voltage between the outermost primary turn and the strike
>shield ring. I have the 1/2" ID copper tubing primary secured
>w/ plastic cable tie-downs to 1 1/2" white PVC pipe through
>pre-drilled holes to run the tie-downs through. The ground ca-
>ble that connects to the strike ring is #6 green insulated
>stranded building cable and it runs though the bottom of one
>of the (8) 1 1/2" dia. PVC primary supports. Could the problem
>be here as the outer primary winding may be arcing to the
>grounding cable though one of the pre-drilled mounting holes
>in the PVC pipe? It was kind of hard to tell the exact location
>of the annoying bright flashover that was taking place when I
>turned the power up, but I could tell it was around the outer
>primary turn and the grounded strike ring. This annoying flash-
>over was what was causing EM problems in the house, too.
>As long as this flashover didn't occur, nothing electronic in the
>house (like the alarm system going off) was bothered.
>
>I just finished building my RF ground system today. It con-
>sists of (4) 5/8" dia. x 8ft. long copper-cald grounding rods
>driven all but about 3" worth into the soil. They are inter-
>connected w/ a bare #1/0 welding cable about 10" to 12"
>under the ground. I run an 18 ft. long piece of insulated
>#1/0 welding cable from the RF grounding post on the coil
>to the RF grounding rods and I think my ground is sufficient
>for my coil.
>
>On a positive note, I didn't have any trace of racing sparks
>on the secondary at any power level so I'm not overcoupled.
>The bottom-most secondary coil is about 1 3/4" above the
>top of the innermost primary coil. I could even try to increase
>the coupling a bit but I don't think that the secondary needs
>to be lowered much more relative to the primary coil on a coil
>of this magnitude. No racing sparks are good ;^)
>
>Sorry for the long post but I knew if anybody could help w/
>this, it would be you guys on this list ;^)
>
>Thanks in advance,
>David Rieben


David,

I use a four electrode rotor on a 3600 rpm motor that I also bought from 
Bill Wysock.  Power is 14.4 kv at 7 kva.  Primary cap is .05 ufd.  I have a 
John Freau phase adjust system that allows adjustment from 120 to 240 
bps.  I normally run at 240 bps as the coil is possibly slightly 
overcoupled and seems to be overpowered at 120 bps.  Your coupling sounds 
like it would allow 120 bps.  I would try removing one half of the 
electrodes, won't hurt anything.  Be careful getting the electrodes out.  I 
have used a vise and sockets, takes about four hands.  Select a socket or 
other hollow cylinder that just fits over the electrodes.  It needs to be 
as long as the electrode plus the thickness of the rotor.  Place this over 
the electrode and put it in a vise or press and push it out using a socket 
just a little smaller in diameter than the electrode to push with.  It is 
easy to damage the rotor if you are not careful.  Before I got the sync 
rotary put together, I used an asynch rotary running at 500 to 600 
bps.  When I went to the synch rotary gap, the performance of the coil was 
not increased and was in fact the same.  It runs much smoother now 
however.  Primary current is much more stable.

About the primary to strike rail flash over - it happens occasionally on 
both of my coils.  Annoying, but not a big problem for me.  All I can 
suggest it to move the strike rail farther away or maybe remove the 
outermost turn on the primary.  You really should try to find out if it is 
the strike rail ground lead and re-rout it if necessary.

Ed Sonderman