Re: Car Coil

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

Original poster: "Steve Greenfield by way of Terry Fritz <twftesla-at-qwest-dot-net>" <alienrelics-at-yahoo-dot-com>

The problem with this is that part of Tesla's
contribution was design of the brushes in DC motors to
reduce arcing and losses. That means that the power
drawn by a DC motor is probably a bit to "constant" to
provide much of an interrupted DC current.

DC motors are multiple pole and are make-before-break
so I just can't see this working very well.

I don't think I'd want to run a Tesla coil near my
vehicle. Just seems like tempting fate more than
usual.

Just my 2 cents,
Steve Greenfield

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> 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


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