Re: Sync 200BPS improvement, (long post !)
In a message dated 99-07-23 05:46:29 EDT, you write:
<< Hi John, Reinhard, all,
> Just thought I would inform the list about a simple improvement which
> I discovered with the 200BPS sync gap idea. It improves power factor, and
> total power throughput and also seems to get round the problem which
> Reinhard had with his particularly stiff neon supply. (7.5kv -at- >700mA!)
Thanks for these most interesting ideas. Terry also recently speculated
about using offset gaps, to take advantage of charging voltage along
the ac waveform. I didn't have good results using them with sync
gaps, but I did not spend time optimizing them. I was running a higher
break rate, and radical offsets. I had good results using offsets with
non-sync gaps. More below.
> we naturally
> make allowances for this by setting the phase to get 2 equal bangs per
> cycle when running at 200BPS. I now realise that this is not optimal,
> and it got me thinking about when John Freau mentioned unevenly spaced
> electrode tests.
> Using evenly spaced electrodes:-
> Gap firing volts = 19.0 kv
> Power throughput = 1690 W
> Supply VA drawn = 1887 VA
> Power factor = 0.896
> Using unevenly spaced electrodes:- (spacing ratio 4.25ms/5.75ms)
> Gap firing volts = 21.1 kv
> Power throughput = 2097 W
> Supply VA drawn = 2216 VA
>Power factor = 0.946
> This improvement seems worth the effort of offsetting every other
> electrode. In my case every other electrode would need moving about
> 6mm. I am seriously considering doing this with the new gap design.
Yes, this is very impressive, and well worth the effort in my opinion, and
yes, I agree it would take better advantage of the inductive kick. Most
interesting about how it improves the power factor too. In my tests at
200 bps, the charging efficiency wasn't as good as at 100bps, maybe
this offsetting will be beneficial for that too?
> Although it is accepted that 100BPS can give bigger sparks, I still
> like 200BPS sync because of its smaller capacitor size, and its better
> ability to keep the voltage under control over time. It makes a cool
> sound and although the sparks are a bit shorter they look a little
> brighter ?
Yes, it does give a cool sound, and they might be brighter, and yes,
cap size, and bang size will be smaller. The smaller bang size has
the advantage of being less destructive to electronic equipment in
the TC vicinity. But I'm looking for longest lengths :)
> Time to try the idea out on a real coil, and see if reality matches the
That will be the acid test as they say.
> Comments, (and any reasons not to offset electrodes)
> welcome as always.
Now that I re-think it all, based on your simulations and comments,
I think it sounds very good. I certainly don't see any reasons not to
offset. If it can improve power throughput and power factor, those two
advantages will be reason enough to *always* use offset gaps when
running at 200/240 BPS synchronous. BTW, I noticed that in some
of your old 200 BPS simulations, the best power factor was not
obtained with a reso-cap. At 120 BPS, I'm seeing best power factor
at or near reso. Did you do simulations with different cap sizes in
combo with different offsets to see how it all interacts?
Nice findings Richie,
> - Richie,
> - In sunny Newcastle.