At 08:56 AM 10/27/03 -0500, you wrote:
Malcolm Stebbins wrote:
Marshall; Like it or not, it is you who are incorrect. I would refer
you to any Motors Manual or Chilton's for a description of the standard
and the transistorized or capacitive discharge systems of auto
ignition. For a good textbook on the subject I'd recommend The
Automobile Electrical System 2nd Ed. by Barr, Randolph R. and Thomas D.
Flocco. Chilton Book Company; Radnor, PA.
Who said anything about a transistorized system? I was talking about an
old spark coil, from something like a 1960's car.
I.E., "Conventional System" Try reading the post and the suggested
material, for a change. BTW, it was you who introjected the CD system as
being similar to a high voltage pulser, hence by faulty analogy that the
300 + volts from a strobe discharge would produce no more than the 12 volts
from an automobile battery.
Short form: In the conventional or breaker-point ignition system the
primary voltage generated by the rapid collapse of the primary winding's
magnetic field is approximately 200 to 300 volts; this collapse is
considerably more rapid than the originating field buildup, hence the
higher voltage.
OK, that is exactly what I was saying. That when the points open there is
a rapid collapse in the field that generates a voltage of serveral hundred
volts, and that is what gets coupled to the secondary for the spark.
The ignition coil is a transformer of approximately 100 to 1 turns ratio,
thus 20,000 to 30,000 volts is induced in the secondary winding,
Once again exactly what I said.
On the contrary, you said 50,000 to 100,000 secondary volts was induced by
a primary pulse of 1,000 volts, which was in turn generated by the collapse
of a field generated by virtue of a 12 volt EMF.
which is more than sufficient to produce a spark at the spark
plug. Under normal conditions of rapid cycling of this system to supply
ignition, and the generation of considerable heat in the coil and under
the hood, the system was just about at it's upper functional limit. The
Transistorized and/or "capacitive discharge" systems were a sorely needed
improvement which relieved the distributor points of massive intermittent
loads and arcing due to back EMF, leaving them the much easier duty of
signalling a transistor or SCR to turn on and off the current to the
coil's primary winding. This they could do even more rapidly than the
opening points did, producing higher primary collapse voltages up to
350. Eventually points were replaced entirely by optical or magnetic
signalling devices which didn't wear - thus the 50,000 mile tuneup and
considerably more accurate and competent ignition.
So the transistor ignition works the same way as the stand one, so I am
even correct for it as well.
About as "correct" as you have been so far . . . . . . in neither of these
systems has the primary field collapse generated anything like the 1,000
volt pulse you posited.
There are no automotive ignition systems running 50,000 to 100,000 volts;
not only is there no need for such a dangerous level, the corona
discharge initiated by such would be extremely and rapidly destructive to
the elements of the system, make the design of a distribution system for
the spark considerably larger, more difficult and expensive, generate a
great deal more RF interference, and be an absolute bear to keep
functional in damp weather.
OK, so I am a little high on the output voltage. That was not what the
message was about, it was givin the information that you just gave above,
that the turns ratio is only about 100:1, and that the spark is generated
when the points break, not when they make.
Oddly enough, the message you wrote was about the information you wrote,
and the response I gave was about your errors in that message; your reply
to that was to state that I was incorrect. On the contrary, both strictly
regarding the elements in my response and your description of the
conventional ignition system generally, it was - and is - you who are
incorrect; - get it straight!
You have suggested that dropping 300 volts through this conventional system
is the same as dropping 12 volts through it, and by implication that it
would be perfectly all right to inflict the consequences of this ignorant
endeavor on oneself or another human - That was what your message was about.
I'd STRONGLY suggest that you try it on yourself first; perhaps the
mismatched parameters of the systems will limit the outcome to a bearable
level.
The systems described did not rely on "leakage inductance";
OK, I just checked definitions, and I guess what I meant was primary
inductace. They sure called it leakage inductance when I was at the
University.
<http://www.geofex.com/Article_Folders/xformer_des/xformer.htm>http://www.geofex.com/Article_Folders/xformer_des/xformer.htm
Since the link doesn't seem to work, I can't comment on what you were
taught, other than to say that the definitions I use are and have been the
standard, and well understood for longer than you or I have been alive.
perhaps you meant to say mutual-inductance and self-inductance. Leakage
inductance is undesirable transfer out of the system of energy which
escapes to the surrounding environment, degrading both the system and the
environment. Leakage inductance does not contribute much at all to the
'time constant' in a decently designed system except by a tiny lowering
of the circuit "Q"; the self-inductance of the primary winding retarded
both its field buildup and collapse, and generated the 'back-EMF' that
caused the points to arc and wear rapidly. One role of the condenser
placed across the points was to absorb enough of this back EMF peak to
discourage such arcing; another was to provide a resonant tank for
multiple spark discharge (aka MSD,) in certain newer designs.
OK, primary inductance.
The inductance of the primary of the coil is expressed in two forms, the
mutual inductance between the primary and secondary windings, and the self
inductance of the primary's field upon itself.
The point, which you seem intent on ignoring, is that if you energize a
transformer designed to accept the primary current driven through it by 12
volts and instead dump the current through it that can be forced by 300
volts, you will generate a considerably greater field. When that field
collapses it will induce a much higher secondary voltage - quite possibly
lethally higher, and certainly far beyond 'your' expectations.
Marshall
Take care, Malcolm
At 01:31 PM 10/26/03 -0500, you wrote:
Malcolm Stebbins wrote:
Oh Boy!! that's going to be quite a hit! The coil gets 12 volts from
the ignition system, and generates perhaps 200 + volts on "break" due
to inductive kickback or field collapse; what's going to happen when
it gets 300 + volts and then the xenon tube extinguishes and "break"
comes for that field? I realize the current is diminishing during the
flash, guess I'll have to try it to find out - but I think I'll try
it on the spider first<g>.
Take care, Malcolm
That is incorrect. The spark coil is typically about a 50 or 100 to 1
transformer. When used in an old automobile, the points close, and a
current builds up in the leakage inductance of the coil. This typically
generates some voltage on the secondary, but not enough to cause a
spark. Then when the points open the field collapses with a time
constant set by the leakage inductance, and the small capacitor that is
across the points. The result is that there is a voltage spike on the
primary of the coil or about 1,000 volts, which show up at the secondary
as a 50,000 to 100,000 volts.
If you ever put a CD ignition on an old car you would know that they use
a circuit very much like the one for the pulser, a high voltage
controlled by an scr.
Marshall
At 10:56 AM 10/26/03 -0500, you wrote:
BTW, anyone who has made a home made pulsar can easily make it to be a
shocker as well. Instead of connecting the magnetic coil wound on a
VHS spool to the unit, connect the primary of an old automobile spark
coil to it. Easy, and convenient.
Marshall
bjh...@aol.com wrote:
I have been told that you cannot use new automobiles to shock for
venom. It will kill you. Maybe older vehicles were OK. We have used
the spark plug wire from a 2 cylinder motor. We hold a metal rod
(with heavy welder's gloves) stuck into the spark plug cover. We
stand on a few layers of corrugated boxes flattened out to keep from
being grounded? With the motor running (a welder) I hold the rod,
and my husband gets just close enough to the rod to have it arc, or
have a little electrical bolt strike his skin. We shocked each bite,
or eruption, about 10 or 15 times around them and also in the middle
of them. The man who showed us how to do this used a 2 cylinder
motorcycle to shock his wife's bite with great success. My husband
has waited 2 weeks to shock his. His original bite had already
cleared up. I used CS on it, but he had several eruptions after
that. We have been told that he should have stayed down, and not
been as active as he was (he played basketball several times). Have
been told that it caused the poison to circulate to other sites. He
is seeing a Chiropractor who is using acupuncture, Metal cleanse, and
UV light. She cautioned against too much CS ingestion saying it can
accumulate in body if not cleansed. I was having my husband drink
about 8-16 oz a day before we started to see her. She sent him to a
Dr. to get some antibiotics. The Dr. gave him a shot of Rocephin and
a prescription for Keflex. He said the eruptions looked like Staph.
The eruptions seem to slowly be getting better. He has been seeing
the Chiropractor for 5 days, twice a day. We have shocked the
eruptions twice. We haven't told the chiropractor, though. He
hasn't had any new eruptions in 5 days. Still treating 3. They are
still painful. Thanks for the responses. I gave my chiropractor the
article on using nitro patches. She hasn't commented, yet. The guy
who showed us how to use the shock told me that I should have used my
CS generator to shock it as soon as the first bite started
erupting. He said to wet the area and shock it all the way around
it. I will probably try that if I get stung or bitten. I have a
homemade CS generator made with a 19v adapter.
BECKY
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