RE: [TCML] DC tesla coil

["S&JY" <youngs@xxxxxxxxx>]

Jay,

A few MOT secondaries in series make a good charging reactor.  You need many
Henries of inductance.  You will need a RSG running above 100 BPS to avoid
trailing power arcs when the reactor saturates and acts mostly like a
resistor.  DeQing diode can be a string of 40 or more 1N5408 1 KV diodes in
series.  You should use the PT - it will be more robust and you won't need a
ballast or a Terry filter.  You can make a bridge rectifier with each leg
having at least 30 1N5408s in series.  This is the usual way to do a DC
coil.

But if you want to build a much improved DC coil, add a second pair of
stationary electrodes on your RSG.  One gap charges your MMC, the rotor
rotates a bit, then the other gap discharges the MMC into your coil primary,
and the cycle repeats.  This avoids the RSG trailing arcs, allows break
rates as slow as you want, protects your DC supply since it is disconnected
when the MMC discharges into your primary, and allows you to use a simple
air core reactor of about 50 milliHenry.

--Steve Y 

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of jhowson4@xxxxxxxxxxx
Sent: Tuesday, May 31, 2011 9:17 PM
To: tesla list
Subject: [TCML] DC tesla coil

So i have built a couple regular coils and now i would like to try my hand
at a DC coil. 
I have a two 12kv 60ma NST's or one 15kv potential transformer that i would
like to use. 

My question is in regard to the large inductor that would be on the
secondary side of the HV power supply. 

D oes anyone have a good design for the inductor used in a DC coil
arrangement? What wire gauge to use? Do I need an iron core (i have a 1KVA
core available) or is an air core fine? etc... 

I am guessing that larger capacitor values are preferred on these setups, am
i right on this? 
And what are the typical required values for a deQing diode? 
Is the use of a terry filter still recommended? 



Thanks for the help, 
John "Jay" Howson IV 


"Why thank you, I will be happy to take those electrons off you hands." 

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