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Re: 10KV RMS -at- 300MA for less than $100
Subject:
Re: 10KV RMS -at- 300MA for less than $100
Date:
Mon, 24 Mar 1997 14:08:12 -0500
From:
"Thomas McGahee" <tom_mcgahee-at-sigmais-dot-com>
To:
"Tesla List" <tesla-at-pupman-dot-com>
> Tesla List wrote:
>
> > > According to my C&H catalog, TR9407 "10MFD 660VAC required and included"
> > > You might want to call them up and see what is going on. Also, is 4500VAC
> > > enough to work a coil?
> > >
> > > LT
>
> --
Fellow coilers,
Two of these transformers running in the non-resonant mode produce a
total
of about 5,000 volts. What they lack in voltage they more than make up
for
in current capability. When using these transformers you have to think
things out just a little differently.
Because the peak voltage is lower
than we are used to using, we need to pay special attention to the
capacitor and spark gap. The capacitor should be large. A value of .05
mfd
is about right. The good news here is that the voltage rating can be
much
lower than we are used to working with. Something like .06 inches
thickness
of polyethelene sheeting should be fine. Two or more caps in parallel
would
be good. That way you can also connect them in series later for more
voltage and lower capacitance if you want to use them with a neon
transformer.
By matching the transformer(s) and the capacitor, you will be able to
better utilize the available *power* of these transformers. The idea is
to
make best use of the high *current* capability so the power level is
maximized. Make sure your primary and secondary are tuned to resonance!
The spark gap will have a fairly low High Voltage breakdown point by
Tesla
coil standards, but it will be conducting large currents due to the size
of
the tank capacitor. It is imperative that the spark gap sections are
close
enough to break down at the peak voltage. The spark gap should be three
or
more sections, spaced somewhat closer than what we coilers are used to.
The spark will need good quenching and removal of heat so that it runs
consistently. A so-called vacuum gap works best. A Richard Quick style
gap
is OK, but it is important that there be GOOD airflow. The usual muffin
fan
might not be adequate here. Because the gap will be at lower voltage and
higher current than usual, it is useful if the size of the electrodes is
increased. Not their spacing (we want that *closer* or the same), but
the
physical size of the facing electrodes. In the case of an RQ Gap, that
would mean longer gap tubes. We want to increase the surface area of the
gap. Otherwise the gap will flame excessively and decompose rapidly.
Barry Benson uses a rotary gap. That seems to work very well, as any
tendency to flame is terminated when the gaps separate.
Perhaps a stacked metal plate spark gap with vacuum (suction to remove
hot
ionized air) would be best for this type of transformer. The difficult
thing is to get something decent to insulate the plates to keep them
apart.
It has to withstand high voltage and heat. Mica washers or strips of
mica
are about the only things I know of that might work. Perhaps a ceramic
material might work, but I have never tried any.
Fr. Tom McGahee