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Re: DC TC



At 04:25 PM 2/15/97 -0700, you wrote:
>Subscriber: gweaver-at-earthlink-dot-net Sat Feb 15 15:43:29 1997
>Date: Fri, 14 Feb 1997 20:43:14 -0800
>From: Gary Weaver <gweaver-at-earthlink-dot-net>
>To: tesla-at-pupman-dot-com
>Subject: DC TC
>
>Has anyone built a DC powered Tesla Coil other than a tube type Tesla
>Coil?
>
>A tube tesla coil is basically a pulsating DC Tesla Coil.
>
>A car ignition coil is DC and operates from points that open and close.
>But it's not TC.
>
>I found an artical where someone built a large auto transformer that
>produced 42" sparks from a battery power supply.  It's not TC either.
>
>Many years ago I built a crude Tesla Coil using a DC power supply an 810
>tube and a signal generator to drive the control grid.
>
>It seem to me if a DC power source could be pulsed at resonate frequency
>it would work fine for a Tesla Coil.
>
>The next question is what is the best way to pulse a DC power supply
>with out a tube?  How about a DC power supply with an adjustable charge
>rate for the capacitor bank. The discharge rate threw the spark gap
>could be adjusted to find resonate frequency?  The capacitors would have
>to be sized correctly for the proper charge rate.
>
>With a Tesla Coils operating on a DC power supply it seem like the
>toroid or sphere on top of the secondary would charge up in one polarity
>like a Van De Graff generator.  Would the Tesla Coil produce longer and
>more powerful output sparks at resonate frequency from DC?
>
>For a TC operating on an AC 12K transformer the peak to peak voltage
>swing would be 19,968.volts.  For the DC power supply to be equal to the
>AC example the DC supply would have to be 19,968. VDC.
>
>Assuming it would be possible to pulse the DC power supply without a
>tube would the output sparks at the secondary be longer or more
>powerful?  The same?  
>
>Gary Weaver
>
>Gary,

All this was posted on this list over the Christmas period concerning my
work with DC powered TCs using spark gaps.

Spark gaps are one of the best ways to use DC in a TC.  It is used exactly
as in an AC system.  DC power just allows one to get far form breaks per
second and pour in a lot more energy.  Greg Leyh's giant system is probably
the best example of a really big DC system.

Somehow I get the impression you want to fire the system at the resonant
rate!!!!  Sorry, can't be done with any real energy delivery per pulse
(simple oscillator does this.) Also, the primary/secondary require a certain
magnetic interaction time to achieve best operation for spark output.

There is no way to determine the Tesla coil's output polarity of charge when
producing long, hot sparks!  It is always positive!  This is not due to any
possible application method, schema, winding direction, phasing or polarity
of input power.  It is a matter of arc dynamics and the rate of energy delivery.

Richard Hull, TCBOR