RE: Tesla coil tank circuit based on cap discharge through an SCR

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

Original poster: "Ray Haynes by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ray.haynes-at-home-dot-com>

If we are talking a resonate transformer design one SCR would not work. The
current between the primary and cap is a damped oscillation (AC). Two SCRs
in parallel (or TRIAC) might work but it might be a little tricky triggering
them. If you just want to hit the primary with a big capacitor discharge
that would work but it would be just a basic step up pulse transformer (not
much HV compared to a resonate Tesla coil design). Also the SCR voltage
would have to be rated not for the capacitor voltage but the back EMF
(kickback) generated in the primary after the field collapses. The real
problem is you would, even for a small setup, need very large SCRs that
could handle high surge current. Also if you don't trigger them properly
even correctly sized one can be destroyed. That's way spark gaps are so
popular.

If you are still interested in this there is a type of car ignition system
called a capacitive discharge (CD) that charges a cap to 300V or more and
using an SCR connects the cap to the coil. You might be able to find
schematics for one on the web.

Ray

> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Monday, June 25, 2001 9:08 PM
> To: tesla-at-pupman-dot-com
> Subject: Re: Tesla coil tank circuit based on cap discharge through an
> SCR
>
>
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Fucian-at-aol-dot-com>
>
> In a message dated 6/25/01 11:45:21 PM Eastern Daylight Time,
> tesla-at-pupman-dot-com writes:
>
> Im not sure how they work.Its capacitive disharged right?You know can
> crushers?Think of a small one with a stud mount SCR switching capacitors
> through the primary.Basically its discharging a much higher
> powered capacitor
> through a primary using an SCR as the spark gap.
>
> Matt
>
>