Re: Electronic Ignition drivers for TCs/ which type is best?

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

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net> by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Emil,
Yes, I am indeed referring to a TC driven by an ignition coil.
to see the the schematic of the initial HV generating apparatus go to the
http://hot-streamer-dot-com/temp directory and look for "Ignition Coil HV
Generator.bmp".

There is more- since current output of ignition coil is so low I use a
string of 60 x IN4007 diodes to charge capacitors. The IN4007 prevent the
capacitor from discharging back into the secondary of the ignition coil
between charging pulses. There is a picture of the rectifier at
http://hot-streamer-dot-com/temp.hvrectifier.jpg.

The picture of  the gap I use is http://hot-streamer-dot-com/temp.bigcoilgap/jpg
it is connected
between the +ve output of the HV supply and the grounded negative rail.

With the rectifier I have been able to charge capacitors of up to 22
nanoFarad to the breakdown potential of the gap although it takes some time
especially with larger capacitors.

Fianlly and most importantly , the negative rail is grounded by connection
to a water pipe helps
prevent high voltage RF spikes from damaging the 13.8V PSU.

Jolyon

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, December 25, 2002 4:13 AM
Subject: Re: Electronic Ignition drivers for TCs/ which type is best?


 > Original poster: "Emil J. Schauer by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <eschauer-at-adelphia-dot-net>
 >
 > Are you talking about a TC driven by an automotive ignition coil? If so,
 > what are the detail.
 >
 > Emil Schauer, in Cleveland Ohio
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Tuesday, December 24, 2002 11:16 AM
 > Subject: Re: Electronic Ignition drivers for TCs/ which type is best?
 >
 >
 >  > Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
 > <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>
 >  >
 >  > Tesla list wrote:
 >  >  >
 >  >  > Original poster: "Jolyon Vater Cox by way of Terry Fritz
 >  > <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >  >  >
 >  >  > When an ignition coil used to provide HV for a tesla coil it is good
 > idea
 >  >  > to use electronic switch to turn the primary current on and off.
 >  >  >
 >  >  > One way use a 555 astable to gate the input of an electronic
ignition
 >  > driver.
 >  >
 >  > A known very efficient method to destroy 555s, power transistors,
etc...
 >  > Works, but if you look at the waveforms, there is a great possibility
 >  > that the 555 is being retriggered by the radiated pulses of the
ignition
 >  > coil, and that its timing RC circuit is not doing anything...
 >  > (Ok, I know that with proper construction the thing works.)
 >  >
 >  >  > Electronic ignition drivers come in two main types (i) inductive
 > ignition
 >  >  > and (ii) capacitive-discharge ignition or CDI.
 >  >  >
 >  >  > Which of the two is best for driving a coil that is powering a TC?
 >  >
 >  > Difficult to tell, since a diode in the circuit turns everything
 >  > into a nonlinear circuit. Probably indifferent.
 >  >
 >  >  > My guess is that inductive ignition is better as it gives a longer
 > duration
 >  >  > output spike which might be better for charging capacitors
 >  >
 >  > No difference. The output, even without any load, is not a spike, but
 >  > a smooth almost sinusoidal pulse containing two widely separated
 >  > frequencies. Much as in a Tesla coil with (very) high coupling
 >  > coefficient. With a diode and a capacitor to charge, this waveform
 >  > will appears, approximately, only when the output capacitor is
 >  > fully charged, after several cycles.
 >  >
 >  >  > maybe "inductive" nature of charging circuit better balances the
 >  >  > capacitance of the tank cap but I am not sure here. I do know that
CDI
 >  >  > gives very short output spikes
 >  >  > -possibly not so good for charging capacitors- am I correct or
 > incorrect on
 >  >  > this matter as I am currently using 555-gated Velleman K2543
inductive
 >  > driver.
 >  >
 >  > Look at the output, without sparking, using an antenna and an
 >  > oscilloscope, and you will see a smooth pulse with a high-frequency
 >  > ringing added to it. The frequencies are in the kHz range, usually.
 >  >
 >  > Antonio Carlos M. de Queiroz
 >  >
 >  >
 >
 >
 >