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Re: Sync-TC, latest results
From: FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: Tuesday, October 28, 1997 4:55 AM
To: tesla-at-pupman-dot-com
Subject: Re: Sync-TC, latest results
In a message dated 97-10-28 04:14:49 EST, tesla-at-pupman-dot-com writes:
>snip>
> 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
>>
Hi Malcolm,
Thanks for this info, actually I find it amazing. I'm using a
much smaller cap (.007uF),higher voltage (32kV peak on cap),
and higher primary inductance (350uH?), 120BPS.
yet my results are much poorer; 42" sparks with 430 watts being
provided by the caps. My secondary Q is probably lower since
I'm using #28 wire, but I wouldn't expect that to make the
tremendous difference being seen here, then again, maybe it does.
Your top load (the 22" by 16" one) is monster-sized compared to
mine, at least in thickness, I don't know if that is the key.
There's a mystery here, and I don't know the answer. This has me
completely baffled. Would you care to speculate why my coil
might be weaker than I would expect based on your results, and
observations? I assume you have the specs for my coil but I'll
resend them to you if you'd like. Any comments will be
appreciated.
Coil mysteries for today and tomorrow,
John Freau
---------------------
Forwarded message:
From: tesla-at-pupman-dot-com (Tesla List)
To: tesla-at-poodle.pupman-dot-com ('Tesla List')
Date: 97-10-28 04:14:49 EST
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