Re: [TCML] Massive VTTC!

[Futuret <futuret@xxxxxxx>]

Carlos,

There are two approaches to using thyratrons to replace a spark gap in a TC. 

In one approach
a mercury (slow acting) thyratron is adequate because it's only used to
initiate primary tank ringdown.  When the ringdown is complete, and the
tank is depleted of energy from that bang, then the thyratron shuts off
by itself.  It then has to be triggered again for the next bang or ringdown.
In this usage the thyratron stays "on" during an entire bang or ringdown.
This operation is basically the same as that of a triggered spark gap.
This type would be adequate for varying the pulse rate of a TC.  
A triggered spark gap is probably a lot less expensive however.

In the other approach, a hydrogen thyratron is used because it is able
to shut down much faster than a mercury thyratron.  The fast acting
hydrogen thyratron is able to be shut down during the ringdown to 
actually control and limit the quenchtime.  Such fast quenching might
be useful in magnifier TCs to trap the energy in the tertiary coil, and
thereby possibly increase efficiency.  Faster quenching might also
benefit regular TCs to some degree.

Thyratrons are not designed for reverse currents.  If reversing currents
will be encountered, then a system of back-to-back thyratrons can be
used, along with steering diodes, or special thyratrons which are
built to tolerate reverse currents can be obtained, but they're more
expensive.

I haven't built any such TC's but had considered the possibilities in
the past.  I think you'd need a rather expensive thyratron to handle
the heavy TC currents.   

Cheers,
John  

 

 


 

 

-----Original Message-----
From: Carlos Van Camp <carlos@xxxxxxxxxxxxxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Mon, Nov 8, 2010 8:37 am
Subject: [TCML] Massive VTTC!


Thanks to everybody for the feedback.

I will go down the solid state path if I have to, but if I can, I would like to 

use as much of the system I have already built, to get the 10 ft musical arcs 

that I need...



Thats why I was asking about the thyratrons as an alternative to spark gaps.

As I understand it they are a type of tube, with hydroden gas in them that can 

be triggered into conduction (like a spark gap), but I'm not sure how 

controllable this would be to give me the varying pulse rates that would be 

needed to create a musical coil...



Obviously if I built a standard spark gap coil, the 50kw power supply I have 

would make 10ft easlily.

Surely there MUST be a way to commutate the the discharge of the tank capacitor 

into the primary to simulate the fast rise time of the spark gap, but with the 

varying pulse rate...



Also, I am happy to post some photo's of this monster coil if some one will 

direct me to a suitable site... I am new to this forum and found out the hard 

way that we can't post pics directly...



Carlos

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