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Re: Sync-TC, latest results


From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Monday, October 27, 1997 3:16 PM
To: 	Tesla List
Subject: 	Re: Sync-TC, latest results

Hi John, all,

> From:   FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
> Sent:   Thursday, October 23, 1997 4:19 AM
> To:     tesla-at-pupman-dot-com
> Subject:    Sync-TC, latest results
> 
> All, Malcolm,
> 
> I replaced my ballast core today by removing the original 1/2" 
> threaded rods and 1/8" welding rods, and installed neon tranny 
> "I" laminations in their place. This new core should exibit lower
> eddy current and hysteresis losses.  The potential tranny was
> installed, and the system tuned up.  The sparks seemed to be
> more powerful, and now permited the use of the large 6" x 26"
> toroid (previously the large toroid performed poorly at the 700
> watt power level).  The large toroid required the primary tune tap
> point to be moved to turn  # 24 (previously turn # 20).  The sync-
> gap was re-phased as needed.  Safety gaps (2) were set at 5/8"
> each.  I'm still using the 4 1/4" dia x 23" secondary and the cap 
> is still 0.007uF.  Actual wall-plug wattage is 700 watts (830VA),
> and sparks occasionally reach 46" with a strong strike to the wall. 
> Perhaps it can do a little better with a little more tweaking.
> 
> A question for Malcolm:  In a recent post, you mentioned a coil
> that gave about 5 foot sparks with the caps supplying only 300
> watts.  This is much better than my results, would you be willing
> to re-post the specs for the cap, pri, sec, toroid, etc. for this coil,
> and any pertinent comments?  Thanks in advance.
> 
> Regards,
> John Freau 

Sure. First I have to say that the wallplug figure is a lot higher 
and it was this discrepancy which made me start wondering about 
losses prior to the primary. There is very little leakage inductance 
in the transformer but I don't think that's of much account 
considering I was using a single static gap (fixed firing voltage). 
So here are the specs:

SECONDARY: ~10" diameter
            ~980 turns 0.56mm (copper dia) wire, spacewound with 
identical wire as the plumb (then removed). Winding height about 45".
Ls around 45mH, Cs around 19pF. *New* topload around 19pF additional
to Cs. Ther terminal is pretty messy in terms of finish. Diameter is 
around 22" and thickness around 16" or so (I haven't got it here at 
present so I can't do more than guess). I should note that this 
terminal will give different capacitances above different diameter 
secondaries.

PRIMARY: ~26" diameter
          3 turns 3/8" copper pipe.
          Height about 3-1/2 inches
          L around 12uH
          Cp = 0.1uF near as.

This was prior to adding the new terminal. With this primary and a 
7pF-odd topload (9" sphere about 6" above the secondary), we measured
a maximum (peak) length point to point of 54" on a day when the air 
was extremely dry.
   The new primary spec is 4 turns in an extra inch of height, 
inductance around 18uH, same cap. The Q was noticeably improved as 
seen by the waveform captured on the storage scope.


GAP FIRING Voltage: < 8kV
2 x Fmains = 100Hz  (transformer can't charge cap any faster than 
this.

Output was extremely intermittent as outlined in another post but the 
discharges were real fierce whn it did go. Definitely a coil for a 
sync gap with pretty close electrode presentation. I think you could
do far better behaviour-wise with same energy but a much smaller cap 
and much higher primary inductance. Peak discharges around 5 feet.

Malcolm