Re: Advice for an Old Coiler

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi Dave,
Welcome back to the world of coiling!

All sounds good but comments on a couple items:

Tesla list wrote:

> Original poster: "Dave Kyle by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<dave-at-kyleusa-dot-com>
>
> Two .03uf 35KV Maxwell caps in series for .015 -at- 70KV

I personally like the idea of maximizing to 70kV with professional caps.
It's possible to run
parallel, but you really increase the potential to kill a perfectly good
gap that way
especially if variac controlled for 140V input. I would recommend keeping
the series bank and
if you want to add capacitance latter on, then go the MMC route.

> Design goal: I should be very please to see three foot or greater sparks.

You should go beyond that, but may not at first. Part of building a coil is
getting it to
perform well (I'm not going to use the phrase "efficiently").

> Questions:
>
> Do you think I would benefit from additional caps. If so how much? I was
> thinking of doubling to .03uf if needed.

I don't think so. 0.03uF is getting up there for a 60mA sync gap coil (time
it takes to charge
the cap is 37.5ms with electrodes lining up every 8.33ms if 120 bps is
used. I think there
will be a lot of miss firings and the firing voltage will fluctuate from
break to break. But,
I'm use to running a pole pig and not lower current transformers, so maybe
others can comment
here on their experiences.

> What diameter disk is recommended for an 1800 RPM SRSG? I was thinking 6
> inches but others seem to prefer wider disks. Why is that?

Smaller disk size would be easier on the motor. As John mentioned, a good
reason for larger
diameters is mechanical dwell time. I think there are a few smaller disk
sizes that have
worked pretty well. Not sure what the actual benefit would be for your coil
between the two
but if your using a dinky motor, a smaller sized disk is probably appropriate.

> How wide to adjust the gaps in a SRSG?

Keep them narrow, about 0.01". Check rotor for wobble and while running.
This will affect how
close you can get the stationary's. The RSG uses timing to set the break
point, and in turn,
set's the conduction voltage unlike a static gap where gap spacing sets the
conduction
voltage.

> My synchronous motor may need to be replaced as I am unsure if it is of the
> type that syncs from the same position at startup. It is a brand new
> synchronous motor from Oriental Motor. Has anyone any experience with these?

I have a little experience with Oriental sync motors. If I'm not mistaken,
your motor requires
a cap in the line voltage? I think this sync will require the motor to be
rotated at each
start up to find the best breakout piont on along the AC waveform. If this
is correct, you may
want to scrounge up a different motor.

> Where can one purchase a 24x12x6 spun aluminum toroid? How much should I
> expect to spend?

See, the toroid bulk buy post. A 9 x 30 was (is) $273 minus shipping. This
includes a quantity
discount buy (we have 20 coilers doing this). I'm sure you can still get in
on it. See the
other post.

> All suggestions welcome, I prefer to stand on the shoulders of giants.
>
> Thank you!
>
> Dave

Take care,
Bart