Re: 15 KVA RSG price

At 17:06 15/01/99 -0700, Cabbott wrote:

>Many people have been inquiring about my beautiful spark gap and its cost
>to me.  Here are the details

... Snip ...

>again, the picture is available here:
>Bill Wysock is willing to give a small quantity discount if enough list
>members need gaps just like the one i got.

Nah ....... much rather build my own, but then I'm a little strange like
that ;-)

Won't be able to match Bill's machining, but the general format has been
VERY instructive.

I had been trying to follow the format used by Brent Turner (he didn't
invent it I'm sure, but has some good instructive pics on his site), of
establishing communication around an insulated disc using a peripheral
conducing plate.  See neat example ...


In the absence of machining facilities this format is quite difficult to do
well.  There was a thread last year on using conductive rotating discs
which were then isolated from the motor shaft, but again this sounded a
little difficult.

Bill's format has a couple of advantages.  One we double the number of
moving gaps, with improved quenching and increased power handling capacity.
 This has to be better than series static gaps as cooling is included with
the windage.

I get to my new house in 2 weeks, so may be able to restart construction
thereafter.  I think a novice like me could make a fairly reasonable gap
using this format.

Rotating electrodes can be done various ways......

1. Cheap.  Use threaded brass rod with a retaining half-nut each side of
the disk.  If you wanted it neat the thread could easily be removed from
the ends of the electrodes.

2. High power.  Off the shelf 4.8mm TIG tungsten electrodes are 150mm
length & could be cut to and ground to suit. Then use grub screw retainers
cf Bill's RSG.

( Remember not everyone can affort tungsten.  If I got two electrodes per
150mm rod and neaded 10 rotating + 4 static, this would be 7 rods at $20
each !!! )

The static electrode mount at the front could easily incorporate heat-sinking.

Stand-off insulators are fairly easy to come by.

All-in-all ...... much food for thought !!

Thanks Cabbott (and Bill !!)