MOT supply continued and spark gap

From:  Marco Denicolai [SMTP:marco-at-vistacom.fi]
Sent:  Monday, June 15, 1998 12:33 AM
To:  tesla-at-pupman-dot-com
Subject:  MOT supply continued and spark gap

I found a solution to my problem of blowing my 10A fuse with the RQ gap: I use
in series with my two MOT/doubler tank supply the secondary of a third MOT,
like a reactor. The connection order is MOT/doubler -> reactor -> safety gap
-> filters -> main gap -> primary cap and primary.

Somebody will say I re-invented the weel: right, I am a beginner, after all...

My tank supply outputs 8KV AC at 0.5 A that makes maybe something between
2 and 3 kW, considering the voltage doublers. My primary cap is 0.05uF and
primary coil about 12 uH.

With this configuration a can run almost one minute runs, being the only problem
my RQ gap that gets hot.

I also learned the 3 mH filter inductors DO stop high frequencies! The potential
developed at their terminal was able to flashover and short them (they are
toroids). I had to add space between terminals and cover them with more layers
of sellac.

Now the source of my worries is (again) the spark gap. I use a RQ static gap
with a blower and 11 cupper tube sections. Each section is 5 cm long and 2 cm
of diameter, the tube spacing being 0.8 mm (0.03"). 

If I connect 5 gaps, the sparking is intermittent and unreliable, depending
on the degree of polishness of the gaps. In practise I have to sand clean
them after each 1 minute run. If I use 3 gaps in parallel with 3 gaps I get
reliable sparking, but the cupper tubes get hot quickly and the gap cupper
tube surface changes color to a shining blue-gray color.

Does this mean my TC is asking for a rotary gap? What do you guys think
about it?


 Marco Denicolai                   Vista Communication Instruments, Inc.
 Hardware Development Manager      www.vistacom.fi   

 marco-at-vistacom.fi                 Kaisaniemenkatu 13 A
 fax:    +358-9-622-5610           SF-00100 HELSINKI
 phone:  +358-9-622-623-15         Finland

   Remember, Murphy was an optimist! I am not...