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,

> From:  L.Robertson [SMTP:LWRobertson-at-email.msn-dot-com]
> Sent:  Monday, June 08, 1998 1:11 PM
> To:  Tesla Builders
> Subject:  H-Bridge Rotary.  Was Last Erg.
> Bert and all ...
> Let me try to explain why I think I won't need ballasting,
> even with a pig. Of course the last laugh has been on
> me before, but this time I think I have an airtight case.
> A short description of my setup - it has been some 
> time since the last go round [:-)
> A variac feeds the HV transformers, as we still need
> voltage control to keep things from getting out of hand.
> HV AC goes straight to a diode bridge, then through an
> RF filter to a storage cap, 1.8uF -at- 60 kV. The primary
> resonance cap is alternately pulse charged positive and
> negative repetitively by the rotary gap. This primary cap
> is now 0.012 uF, so each bang takes about 1% of the
> energy in the storage cap.
> There is never any short across the transformer output
> as there is when the gap fires on an AC coil. The faster
> the rotary turns, the more times per second the small
> cap is charged; and the more current is necessary to
> keep the storage cap full, but the transformer never sees
> intermittent low impedance loads, and thus, I say, doesn't
> need a current limiter.
> Except in case of component failure, where I'm hoping
> a circuit breaker will do.
> Cheers ...
> LR