H-Bridge Rotary. Was Last Erg.

From:  Julian Green [SMTP:julian-at-kbss.bt.co.uk]
Sent:  Wednesday, June 10, 1998 4:56 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: H-Bridge Rotary. Was Last Erg.

> From:  Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
> Sent:  Monday, June 08, 1998 10:37 PM
> To:  Tesla List
> Subject:  Re: H-Bridge Rotary.  Was Last Erg.
> Hi Larry,
>             I had a similar idea to yours several years ago and 
> popped the question to an experienced coiler at the time. He said he 
> had tried exactly the same thing and got kickbacks that blew 
> lightbulbs in a neighbour's house! His initial thought was that he 
> was connecting a partially charged cap back up to the mains but my 
> thought is that he was in fact slamming a short across the mains at 
> an unfavourable point in the mains cycle (see the lights dim when 
> you switch your computer on sometimes, right?)  Connecting a cap to 
> the mains at the peak of a sine is placing a temporary short across 
> it. I think you cannot judge how an unballasted setup is going to 
> behave from the behaviour of a ballasted system. I concur with Bert 
> Pool - I think you may find unexpected problems.
> Best of luck anyway,
> Malcolm

I have a coil that is powered by a pole pig and has no/little balast.  
5 ohms mains wiring resistance at 240 volts - its all down to the spark 
gap that I use.   

If I use a multi static gap like the richard quick type I have kick back
problems and blowen fuses, lights dim etc.

If I use my rotary which is literally thrown together it runns smooth.
I have an amp meter on my variac and when the coil is running its shows 
a steady 12-15 amps depending on how I adjust the spark gap.

The spark gap is based on a 10,000 RPM motor and uses electrodes 1/8" 
diameter on a 6" diameter disk, so the dwell time is short.  There's a 
picture of it at www-dot-netcomuk.co.uk/~wwl/uktesla.html.

The spark gap is not very good, but it works.   It shows that it is
possible to have a pole pig powered coil with minimal balast.

NOTE:  A coil powered at 8KV using current limiting and richard quick
type spark cap out performed my voil powered by 11KV pole pig and 
rotary gap at a recent teslathon :(

Julian Green