Car Coil

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

Original poster: "Matt Skidmore by way of Terry Fritz <twftesla-at-qwest-dot-net>" <fox-at-woozle-dot-org>

I know its been covered before, but i thought i'd hit upon something new
for building an automobile powered coil. And its 3 am and i cant stop
thinking about it.

But, i was having a lengthy conversation with one of the electronics
professors at my college about my tesla coil hobby. I brought up a
question about how one might run these beasts using a dc source. sure
there are oscilators and tubes if you can think about ways to get them to
work but he showed me a rather simple idea. he suggested using a dc motor
to create the signal needed to drive a standard ac transformer. of course
this would be more of a pulsed dc signal.

intreaged, i carried a 12kv 60 ma neon transformer down to the lab for
futher experimentaion. i hooked it up to a signal generator to the low
voltage side and put a volt meter across the HV end and started fooling
with the generator. i set the generator to square wave to simulate pulsed
dc. it outputting 15v rms (not peak to peak) measured with a volt meter. i
found that i got the highest results with square wave at 700 hertz. to
futher simulate the pulsed dc i put a diode on one of the terminals going
into the LV side. it cut my HV voltage down to 215v. still not bad.

ok so you may be thinking so what? well if you can get some high current
drawing motor such as a starter motor and use it to create the pulsed dc
to drive a transformer then you might be able to make a car coil. the
transformer could be something like an ignition coil, or 1 or 2
transformers to crank up the voltage.

i know theres problems. but theres also benefits here too. first off, the
motor is going to run at an unknown frequency. but hopefully better than
60 hertz and not so fast that it will pass up the maximum "sweet spot" on
the transformers (which was 700 hertz for mine). also, since the motor is
creating the frequency then it would be also useful for being a perfectly
phased spark gap. i drew up an illistration you get hit up:
http://foxxz-dot-net/tesla/carcoil.gif

grounding. if you're going to try and run this off your car, then you can
try and go ungrounded or you can try this other trick. i was talking to
the aviation fuel truck driver at an aitport where my father works. there,
they have to keep everything perfectly grounded while fueling up as not to
set the place ablaze. before the trcks started using special tires, they
drug a short length of chain under the truck to help discharge. this might
work somewhat well if youre attempting to ground a moving object.

of course i realize all the dangers of running such things near flamable
liquids and that it could potentially fry electrical systems of the
vehicle. but on another thought, one could also install a second
alternator to run their coils from too.

dont take me too seriously :D
-matt