Re: I'm Sold on MMCs and RSGs! - Pics

["Finn Hammer" <f-hammer-at-xxxxxxxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

Gang!

A 3000/3600 rpm Motor needs 2 flats, and 2 electrodes for 100/120 BPS
A 1500/1800 rpm motor needs 4 flats, and 4 electrodes for 100/120 BPS
A 1000/1200 rpm motor needs 6 flats, and 6 electrodes for 100/120 BPS

This is assuming 50/60 Hz and 2 static electrodes, if the rotating
electrodes are connected electrically, or 2 static opposing electrobe
_pairs_ in which case the flying electrodes are not connected
electrically, but act as flying "triggerslugs" btwn. the opposing fixed
electrodes.

Higher breakrates are possible, by multiplying the flying electrodes,
but this is not smart, if equal bangsize is the goal. In this case it is
better to use more fixed electrodes, which can be adjusted. There seems
to be no intuitive approach to positioning these electrodes, but:

>From numerous Microsimulations, and practical verification, a suitable
pattern has emerged, for positionong these fixed electrodes. In a 50Hz
system, where each half cycle lasts 10mS, the electrodes should be
positioned at approx.
First:  2.0mS - 2.5mS
Second: 6.4mS - 6.6mS
Third:  8.8mS - 9.0mS

I have tried this on my museum coil, and found these numbers to be
representative for a system running at around 3kW -5kW and I am in the
process of setting this investigation into system, with my new coil that
allows realtime adjustment of all 3 stationary electrodes.

This is with a special SRSG that runs at 3000 RPM, but has only 1 gap,
because the charge is transferred to the 2 flying electrodes by a
centermounted slipring. I will talk more than enough about this, when it
is finished.

My page about setting 300 BPS with equal bangsize is at my site:
http://home5.inet.tele.dk/f-hammer/tesla/tesla.htm

Cheers, Finn Hammer

Tesla list wrote:
> 
> Original poster: "Barton B. Anderson" <tesla123-at-pacbell-dot-net>
> 
> Hi John F., Robin, Andy,
> 
> Tesla list wrote:
> 
> > Original poster: FutureT-at-aol-dot-com
> >
> > In a message dated 11/27/00 1:15:43 AM Eastern Standard Time,
> > tesla-at-pupman-dot-com writes:
> >
> > > Andy,
> > >
> > >   I assume that you have cut four flats into the armature of your
motor as
> > >  it's a 1200
> > >  rpm unit. You mentioned 6 electrodes on your disk and this is where your
> > >  problem is.
> >
> > Robin,
> >
> > A 1200 rpm motor uses 6 flats to make it synchronous.
> >
> > John Freau
> 
> Yes, 1200 rpm using 6 flats = 120 bps, but the breaks are not divided
evenly on
> each half cycle.
> 
> Assume one half cycle. This indicates 3 breaks during that half cycle.
Now try
> to divide 3 breaks evenly along that half cycle (can't be done). The best you
> could do is to manage 2 out of 3 as 1 will be near zero crossing. I would
also
> expect that a break through zero (not firing) could occur often and cause a
> charging imbance from break to break.
> 
> A 1200 rpm, 6 flat RSG is only synchronous in that it can lock to the mains
> cycles, but it should not to perform well as indicated above. I beleive
the old
> RSG program ROTJIT showed this as well.
> 
> Bart