[Prev][Next][Index][Thread]

Re: Help in calculations



>From: Charles Brush <74040.3317-at-CompuServe.COM>
>To: tesla-at-grendel.objinc-dot-com
>Subject: Re: Help in calculations

>>I tend to side with
>>the theory that letting the tank circuit capacitor decide when
>>Vmax occurs is best. When the voltage peaks (meaning the cap is
>>fully charged and the line voltage rises due to the reduction in
>>current flow into the capacitor), the static gap should fire if
>>it is properly adjusted. The peak power should be delivered if
>>the gap is rapidly quenched after firing. 

>Hi Richard,

>What are your thoughts on this subject with regard to pole pig powered systems?
> Not having gotten into this myself yet, I've been wondering if you'd ever run
>into problems with an asynchronous rotary gap going in and out of phase with
>the charge time of the caps.  I.E. the caps occasionally reaching Vmax when the
>rotary's gaps are not aligned for firing.  Have you or others here ever heard
>any "beating" in your rotaries or noted any in the coil's output?  I realize
>that rotaries are the norm on larger systems due to quenching problems with
>static gaps, but if some sort of "super" quenching static gap was possible
>would this be ideal? (in terms of always allowing Vmax...I realize that this is
>theoretical and might not be practically possible)   

>Charles Brush

Charles,

With a variable speed rotary and pole pig system you can actually 
set the rotary speed to 'beat' with the 120 available charging 
envelopes per second on the 60 Hz power line.  Setting your speed at 
120 PPS willl give you this effect most pronouncedly, 240PPS as well 
but less effectively,  and so on.  If you get the speed of your rotary 
really close so that the phase difference changes slowly, say 360 
degrees per 5 seconds, then you will get an output streamer that 
dissappears, reappears, grows slowly to maximum, recedes and 
dissappears, the cycle repeating over and over at a 5 Hz rate, or 
whatever is your 'beat' frequency with the line.

In operating in this mode I have never experienced any kind of problem or
component failure (with a pole pig). I suspect that this may be an invitation 
for destruction of a neon however with a number of factors which come 
to mind possibly conspiring  together to overvoltage the neon secondary however.

The first time you see a coil operated as described above it becomes 
immediately clear that use of a truly phase steady, synchronous 
rotary gap would permit maximum power thruput simultaneously with 
maximum efficiency for a given classical two coil system.  I don't 
have enough observational experience with a coil running in phase 
sync to answer this, but I'll throw out my idea for possible comments 
from others.  The display we've all come to appreciate is a streamer 
that constantly slithers around always 'looking' for a new target to 
strike, it may sit on one for up to a second or so at most when it 
really seems to 'connect',  but then it will with lightning like 
suddeness (how's that for an analogy!) reappear in a completely 
different place.   In a non-synchronous rotary system there will be a 
beat frequency which is often high,  this very rapid
pulsing in and out which our eyes don't have quick enough response time
to see, repetitiously provides enough off time that the long air ionization 
path has time to recombine and become an insulator again between 
strokes.  Which is then why any random and different direction is 
continuously an attractive path for the streamer to take.  Now for 
the $64 question.   By eliminating this slow pulsation by 
going to a true SRG, would the streamer produced have a noticeably 
different 'personality'?, i.e.,  one that would tend to attach itself 
to something and sit there trying to melt it until power was 
terminated, or a gust of wind blew it off target, or the target 
actually melts out of reach of the streamer?  My best answer to the 
above postulated question of personality change  based on my 
experience with true CW output vacuum tube TC's would be 'somewhat
or more so' as compared to the non-synchronous rotary.  In a multi-kilowatt
vacuum tube TC system, once a streamer finds a target it becomes a contest
to see which will melt first, the target, or the TC oscillator tube and or
its power supply!

Comments anyone?

Happy coiling!, rwstephens