sync-gap problems

From:  Gary Lau  29-May-1998 0819 [SMTP:lau-at-hdecad.ENET.dec-dot-com]
Sent:  Friday, May 29, 1998 7:33 AM
To:  tesla-at-pupman-dot-com
Cc:  ajones-at-nwga-dot-com
Subject:  Re: sync-gap problems

>From:  ajones-at-nwga-dot-com [SMTP:ajones-at-nwga-dot-com]
>Subject:  sync-gap problems
>I've just completed an 1800 rpm sync-gap system. The rotor has 4
>electrodes through its face and two stationary electrodes. The motor
>can be rotated nearly 180degrees, also. 
>My problem is no spark at the toroid. The rotary makes a dull thudding
>noise when the gaps fire with or without any static gaps in series.
>The static gaps also make this noise when used with the rotary.
>When I remove the rotary from the circuit and use the static gaps, the
>system works fine. This is the first rotary I have used so I don't
>know much about them. I'll eventually figure it out, of course, but in
>the meantime I'm open to suggestions.
>Alan Jones

Hi Alan:

I'm also rebuilding my sync rotary after poor results (~30" w/ sync RSG, 42" 
w/ only static gaps) the first time around, so I'm no expert.

I'm also puzzled about the noise you describe.  I assume it not due to gaps
or anything else mechanically crashing.  I noticed that in mine, the sound of
the system was distinctly 120 Hz, very different than with static gaps, but I
believe this noise was coming from the output discharge mostly.

Could it be that your rotary gaps are too wide and that it's taking multiple
half-cycles for the tank cap to ring up to the gap's firing voltage?  (Very
bad for your NST(?) and cap!)  Could the gap spacing be changing as it spins

Gary Lau
Waltham, MA USA