[TCML] newbie question rsg
Mddeming at aol.com
Mddeming at aol.com
Thu Nov 15 11:24:06 MST 2007
In a message dated 11/15/07 8:53:54 A.M. Eastern Standard Time,
kc5gym at cox.net writes:
if a rotary spark gap is to allow the tank to charge at full potential of
the 60 hz sine wave, then how does a spark gap of over 120 bps offer any
With an Asynchronous rotary gap, as the bps is increased, you will reach
points where occasionally there will be two charges/discharges of the cap for
a half cycle of the supply voltage. While these take place at less than full
voltage, two pulses per half cycle at say, 75% voltage, will put more
average power into the secondary than one pulse at full voltage. At certain ratios
of gap speed to line frequency, enough sub-optimal pulses occur that there
is an increase in the average power throughput to the streamer per second.
Added to this is the fact that a spark gap is not a precision switching device.
It's on and off times tend to wander slightly over the space of a
second,(heat, air currents, oxidation, residual ions, etc.) which is a long time at TC
frequencies. If this happens enough times per second, you get some advantage
from the more frequently recurring double pulses. The net result will be
occasional longer discharges, occurring somewhat less frequently. Here again, we
are talking "more and less" on very short time scales. Some folks like it that
way, some don't. If you look at the discharge frequency of a static gap, you
will find that its average is close to, but slightly above line frequency.
With a DC coil, of course, the pulses can be fine-tuned with a variable speed
gap to match the exact capacitor charging time, and this is where, IMO, they
are most useful. I believe that a majority of the AC-powered coils that do
use rotaries, use Synchronized ones.
Hope this helps,
"If two engineers agree, fire one of them - Don't pay twice for the same
--Old Bell Telephone Labs internal slogan
************************************** See what's new at http://www.aol.com
More information about the Tesla