Re: 555 driven ignition coils

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: 555 driven ignition coils
From: Tesla List <tesla-at-stic-dot-net>
Date: Sun, 23 Nov 1997 23:37:34 -0600
Approved: tesla-at-stic-dot-net


From: 	Edward V. Phillips[SMTP:ed-at-alumni.caltech.edu]
Sent: 	Sunday, November 23, 1997 1:39 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re:  555 driven ignition coils

"With the circiut I made, the spark would jump from the HV terminal to ground
consistantly if I pulled the HV lead out and cranked the motor - that's a
spark length of a couple of inches.  (and the car ran better).  This same
approach might be useful for a battery powered tesla coil.
-----Original Message-----"
	After being inspired by a design from Tedd Payne, I built
an SCR driver (actually a quadrac, but same general idea) to GM
high-energy spark coils (which are available auton salvage shops
for $5.00 around here - make that auto salvage shops).  With 1.5
ufd capacitor charge to 600 volts it will produce 3" sparks from
one coil, PROVIDED it is placed in oil to keep it from arcing
over on the surface.  Two coils in series ("bottom" of each HV
winding to ground, as the primary-secondary insulation won't take
it) will push 6" when hit with a 3 ufd capacitor charged to the
same voltage.  Circuit is a resonant-charging type, with HC
HV brought in through an inductor and a diode.  As a result,
the capacitor charges up to twice the DC supply voltage.  I
have also run the things from a 12 V battery, using a small
switching converter.
	I have published the schematic for this thing on the
list, and will send it along to anyone interested.
Ed