Re: home brew tachometer

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Metlicka Marc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>

Justin,

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Pyrotrons-at-aol-dot-com>
> 
> Hi Mark, all.
> 
> I suppose the light-beam reflecting from the disk onto a photodiode would
> work to make the pulses (for counting), but here is a better, easier way to
> do things. This method requires that your stationary electrodes protrude
> toward the disk a little ways, it also requires an oscilloscope.
> 
> Step 1: Coil a bunch of wire (20 turns or so, doesn't really matter) onto one
> of your stationary electrodes. Put a magnet on the stationary electrode
> somewhere. The coil will output a little pulse of voltage every time an
> electrode flies by. Put the coil's output on Channel 1 of a 'scope.
> 
> Step 2: Put channel 2 of the scope directly across the secondary of a small
> step-down transformer to get the main's waveform (or just stick it in the
> wall if you want......)
> 
> Step 3: Adjust things to put channel 1's waveform on top of Channel 2's. You
> can immediately see what's going on with your RSG this way. Instantly
> calculate BPS, RPM, and know if it's sync or not. If it's sync, both
> waveforms will stay at exactly the same place in relation to each other.
> 
> ALSO: another method to find out if your RSG is sync or not. If you don't
> have a scope, but DO have a light dimmer, ignition coil, and capacitor
> (triggered gap setup), then read below!
> 
> > Couldn't a simple dimmer circuit like the triggered
> >  gap driver, be used to fire a camera flash lamp?
> 
> Yes, definately. Run the HV output of the coil through a flourescent bulb
> (brighter than a xenon flashlamp), I've tried it, it works great, although
> the phosphors in the bulb flouresce too long. This makes things look somewhat
> blurry, but does work. Our SRSG has 4 brass strips on the backside to connect
> the electrodes, the brass was a perfect square with the synched HV firing the
> lamp (easier to make than a "ring" around the edge since we had the brass
> strips on hand)
> 
> But I thought triggered gaps were supposed to replace sync RSG's......just
> kidding.

Well i think they will in the future, But it will take quite some time
before coilers will except the change.
It IS coming, Terry's work and Berts comments are beginning to open some
eyes, It will take coilers like myself, Terry, and yourself to actually
start doing the experiments and trying things "Just for kicks" (playing,
Tuning, Modifying into a workable setup for  a given tc system) Then the
reports that come about will spawn a desire in other coilers, "because
no coiler wants to behind the times"
One thing I'm working on right now is an electrically controlled gap
spacing, This is nothing more then a linear slide that opens and closes
the gap "on the fly". The problem i'm having is the arc conducting back
to the linear drive? But i'll get it.
a friend gave me an "ERC control" by ADDCO, This unit was the throttle
control on a DYNO. It has great potentiometer feedback and "locks" into
place with clutches that hold.
I'm going to implement it on the adjustable gap as soon as i get the
pinout for the connector.
"GREAT THINGS TO COME"


 The day you run 15kVA through a triggered gap is the day I throw
> (smash, hurl, burn) the rotary away. Rotaries are a major pain (pg-13 here)
> if you don't have access to a machine shop.

I will be pushing 25kva plus through a triggered gap next year, The only
limiting factor is electrode stability and heat sinking. With the proper
design i don't think there is a limit?
Once the electronics "guru's" get started on drivers, I think the
triggered gap is going to bring about some VERY interesting coiling.



> 
> So BTW, what IS the maximum power anyone has ever put through a triggered
> static gap? Couple of kVA? I wonder at what point it's unable to quench. (I
> bet a powerful vacuum triggered gap would work well)

in another post.

> 
> Sometime this week I'll try a triggered static gap -at- 15kVA, this should be
> really interesting. Aron cut some 3.5" copper pipe sections out for a massive
> gap "just to see what happens"....I'll put the dimmer/ignition coil HV on it
> just for kicks too...)
> 
> Kinda along these lines (actually not really), I put my shop vac air hose up
> to the streamers of one of my smallish TC's..............it sucks them in and
> is kinda neat.
> 
> Take care, good luck with your gap's........

We'll be happy to hear much more results as they come in.
Marc M.
geek #1055


> 
> Justin Hays
> KC5PNP
> G-1 #1150
> Email: pyrotrons-at-aol-dot-com
> Website: www.hvguy-dot-com