Which DC Drive?

From:  Steve Young [SMTP:youngs-at-konnections-dot-com]
Sent:  Saturday, June 06, 1998 10:31 PM
To:  Tesla List
Subject:  Which DC Drive?

To DC TC Enthusiasts:
I am designing a DC powered 6 inch TC.  DC supply initially will be two
MOTs, each with two half-wave voltage doublers, these in series for about
10 KV total output.  Output filter cap is about .5 mfd.  Primary cap will
be .02 - .03 mfd.

I know of two ways to drive the TC primary (protective filters, etc. not
1) Charging Reactor (Greg Leyh style): 

   Supply + -- Charging Reactor -- Cap -- 0 
                                 |        0   
                                 o        0
                             RSG o        0 Primary
                                 o        0
                                 |        0
   Supply - ------------------------------0 

2)  Polarity-reversing RSG (Larry Robertson style):  

   Supply + -----------------------------------------
               |                                    |
               o                                    o
               o Gap 1                        Gap 2 o
               |                 Primary            |
               |------ Cap ---- 0 0 0 0 0 0 ---------
               |                                    |
               o                                    o
               o Gap 4                        Gap 3 o
               |                                    |
    Supply - ----------------------------------------         

The gaps are a RSG wherein gaps 1 & 3 fire, then 2 & 4 fire, repeatedly.

Questions:  1) What are the pros and cons of each method as far as
protection of the DC Supply, Primary Cap voltage rating, etc.?  

2) What are the rules-of-thumb for sizing the charging reactor as far as
inductance, peak voltage it must handle, etc. for a given DC supply?  I was
planning to use a
couple of MOT secondaries in series--will that work OK?  

3) I would be interested in coilers' experiences with much less than
Electrum-sized DC supplied TCs.  Seems like the advantages of independent
power and break rate control and probably more controlled and analyzable
operation would attract more coilers than I have seen mentioned on this

Thanks for your help in advance,