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Re: I have a few questions
My answers to your questions (not the only ones of course):
> Original Poster: RWB355-at-aol-dot-com=20
>
> Hi All,
>
> I have a few questions:
>
> 1.) After reading numerous posts on RSG gaps, why would anyone want to bu=
> ild
> an async rotary ? I think sync motors are plentiful (you can turn async i=
> nto
> sync easily by grinding/milling flats on the armature). Sync gaps are eas=
> ier
> on your system. Varying the break rate means going to a little more toubl=
> e
> (i.e. you need a disk and a "x" electrode number for every diffeent BPS),=
> but
> I still think its cheaper and less of a pain in the ... than getting a ne=
> w
> transformer every time you goof up on the async setup.
With a stiff supply or DC supply you can run at any breakrate you
choose and see different effects as a result.
> 2.) Regarding the formula Watts=3D 1/2 CV^2 x BPS/ EFF. How do you calc =
> the EFF
> of a AC system ??!??. I=B4ve heard values from 45% to 85%. That=B4s a pre=
> tty wide
> margin, allowing a lot of "error".
Different systems exhibit different losses. As primary current
climbs, gap losses climb. More gaps in series exhibit higher
losses than fewer according to some measurements I've made
as they have a minimum conduction voltage. Different grounds will have
different losses etc.
> 3.)What is wrong with the formula Vsec=3D(Vpri*Cpri)/Csec ? With a second
> formula Sparklength=3D Vout/3* 10^5V/meter you could easily calc the spar=
> k
> length. Why doesn=B4t this give an accurate value? The BPS would be inclu=
> ded in
> the Vpri variable. Or am I missing something?
You start with Cpri charged to Vpri. Energy it contains =
0.5*Cpri*Vpri^2 Assume all that is transferred to the secondary
without loss. Then 0.5*Cpri*Vpri^2 = 0.5*Csec*Vsec^2 This is basic
energy conservation. The formula you give violates this law. This
assumes the system behaves as a lumped system which a variety of
different tests suggests is a good approximation, esp. with large
toploads.
> 4.) Some of you (i.e. John F., Greg L) are showing values for spark leng=
> th
> vs. BPS. You mention at 1 BPS the coils puts out streamers of so an so le=
> ngth.
> How can you measure a spark length at such a low BPS ?!?. I=B4ve tried th=
> is, but
> the sparks are so erratic (due to the low BPS) I couldn=B4t even give you=
> an
> average of the spark length. I think you would need a BPS rate of at leas=
> t
> 75-100 BPS to give somewhat accurate, constant results.
My personal measure is what the coil can achieve as a single channel
streamer to a grounded rod. For a given Epri, this increases with
break rate reflecting an increase in power throughput (not output
voltage).
Malcolm
> 5.) Here is one last question esp. directed to John Freau. You mention t=
> he
> square law you derived from empirical results. I tried to "resurrect" the
> formula from the watts/sparklength table you mentioned, but without any l=
> uck.
> Could you please pass me the complete formula again ? Why is there such a
> dramatic difference between the J.F. values and the output the JHCTES giv=
> es ??
>
>
> Thanks for the help,
>
> Coiler greets from germany,
> Reinhard